The way to simplify removal of radioisotopes, the method of processing iron and titanium containing material

 

(57) Abstract:

The way to facilitate removal of impurities, for example, radioisotopes of uranium and thorium and/or one or more of their children radioisotopes of titanium containing material includes contacting the titanium containing material with one or more reagents at an elevated temperature selected to increase the availability of at least one of the child radioisotopes in such material. Reagent (reagents) can be stekloobraznoi reagent and it is chosen for the formation of phase at elevated temperature, which scatters on the surfaces of titanium containing material and includes radioisotopes and one or more subsidiaries of radioisotopes. Such material may be, for example, ilmenite, altered ilmenite or synthetic rutile. The method allows to remove not only the radioisotopes of uranium and thorium, and their daughter radioisotopes. 3 S. and 26 C.p. f-crystals, 22 PL.

The invention relates to a method for easy removal of impurities, especially (but not only) of such radioactive isotopes, such as uranium and thorium and their daughter radioisotope from a titanium containing material, and in particular the invention relates to FPIC is A.

Ilmenite (FeTiO3) and rutile (TiO2) are the basic and important industrial mineral raw materials for the metal titanium and titanium dioxide. Although ilmenite and rutile almost invariably are present together in nature as components of "mineral Sands" or "heavy minerals" (together with zircon (ZrSiO4) and monazite ((Ce, La, Th)PO4)), but ilmenite is usually more common. Natural weathering of ilmenite leads to partial oxidation of the iron initially present in the ilmenite in the form of ferrous iron (Fe2+) to ferric (Fe3+). To maintain electroneutrality some oxidized iron must be removed from the ilmenite lattice. The result is a more porous structure with a high titanium content (and lower iron content). These weathered materials known as "modified" ilmenites, which may have a content of more than 60% compared with 52.7% of TiO2in stoichiometric (unmodified) ilmenite. When weathering or alteration of ilmenite, impurities such as, for example, aluminosilicates (clay) are often embedded in a porous structure in the form of small discrete grains that possess this process.

The bulk of its output in the world ilmenite is used for pigments based on titanium dioxide, which are used in dyeing and paper industries. Titanium dioxide, which is used as a pigment, usually obtained by the reaction of ilmenite with concentrated sulfuric acid and subsequent processing for the formation of TiO2-pigment, that is, the so-called sulphate process. However, this method becomes increasingly undesirable from an environmental point of view, since a large number of acidic liquid wastes. An alternative method is the so-called chloride method involves a reaction with chlorine for the formation of a volatile titanium tetrachloride and subsequent oxidation to the TiO2. In contrast to the sulphate method, chloride method capable of processing these raw materials, such as rutile, which has a high content of TiO2and low content of iron and other impurities.

Consequently chloride method creates fewer problems in relation to environmental pollution, and it becomes preferable to obtain a pigment from Dukakis titanium. Also, although the sulphate process can form tormenta based on titanium dioxide. Reserves of natural rutile is insufficient to meet the world's needs in order to use it in the chloride method. So, there is an increased need in making more abundant ilmenite and altered ilmenites (usually 45 - 65% of TiO2in synthetic rutile (containing more than 90% of TiO2).

Regardless, ilmenite commercially available as raw mineral or as rich synthetic rutile, from manufacturers to constantly want their products meet more stringent requirements in relation to levels of content of uranium and thorium.

Thus, there is an increasing need to develop methods for removing uranium and thorium from ilmenite other titanium containing materials (e.g., synthetic rutile).

There is a method of removing contaminants, such as uranium (U) and thorium (Th) from the ore of titanium dioxide by leaching with a solution of inorganic acid (see US patent 5085837, class C 22 B 34/10, 1992). When the leaching is carried out in one or several stages.

When implementing the above method is the removal of uranium and thorium from a titanium containing material, however, radio is because that known method is to remove mainly the parent isotopes of uranium and thorium, and the child radioactive isotopes are not removed to the same extent.

The basis of the invention is to create a way to simplify removal of radioisotopes from a titanium containing material, conditions for the implementation of which would delete child radioactive isotopes in the same way as the parent isotopes, such as Th and U.

The problem is solved in that way facilitate the removal of radioisotopes such as uranium and thorium and/or one or more of their children radioisotopes of titanium containing material according to the invention carry out the contacting titanium containing material with one or more reagents at an elevated temperature selected to increase the availability of at least one of the child radioisotopes in titanium containing material, and select the reagent capable of forming phase at elevated temperature, which is dispersed on the surfaces of titanium containing material and includes radioisotopes and one or more subsidiaries of radioisotopes.

Preferably, when the reagent or reagents include one or more STI and silicates.

Under stekloobrazuyuschego reagent refers to a compound that is converted at elevated temperature in the vitreous, i.e. non-crystalline phase containing three-dimensional atomic grid, usually includes oxygen. Stekloobrazuyuschego compounds can be added separately or in combination or in mixture of two or more compounds. Also reagents that act as modifiers of the glass, i.e. as modifiers mentioned phase grid, for example, compounds of alkaline and alkaline-earth metals, can also be added together with stekloobrazuyuschego reagents. The glass modifiers can be added, for example, in the form of a compound oxide, carbonate, hydroxide, fluoride, nitrate or sulfate. Add stekloobrazuyuschego reactants and modifiers glass can be natural minerals, such as borax, ulexite, colemanite, or fluorite, or chemically synthesized compounds.

Especially effective stekloobrazuyuschego reagents according to the invention in the sense that they achieve optimal incorporation of radioisotopes and daughter radioisotopes in the vitreous phase, include borates of alkali and alkaline-earth metal, more preferably the>1, NaCaB5O9and Na2B4O7which are respectively represented by minerals colemanite, Ca2B6O115H2O, ulexite NaCaB5O98H2O and borax Na2B4O710H2O. Especially preferred are the calcium borates. Effective modifier of glass in connection with these borates is fluorite (fluoride Galicia).

The corresponding high temperature, effective to achieve a satisfactory or better level include radioisotopes, is in the range of 900 - 1200oC, optimally 1050 - 1200oC.

According to the invention of such material may be ilmenite, altered ilmenite, restored ilmenite or synthetic rutile.

Child radioisotopes whose availability is improved, preferably include 228Th and228Ra.

The proposed method can include advanced stage of separation of radioisotopes from titanium containing material.

Particularly preferred application according to described aspects of the invention can be obtain synthetic rutile (SR) from ilmenite by way of reduction of iron. This pic is stravitelne atmosphere in a furnace at a temperature in the range 900 - 1200oC to obtain the so-called restored ilmenite. The furnace also serves the above-mentioned reagent (reagents), the result is a phase that is dispersed on the surfaces of titanium containing material and includes radioisotopes and one or more subsidiaries of radioisotopes. Chilled restored ilmenite or synthetic rutile, remaining after subsequent water iron oxidation and separation of iron oxide, is subjected to acid leaching. Part of radioisotopes can be removed during the stage of water oxidation.

The problem is solved that way for ease of removal of radioactive isotopes of titanium containing material according to the invention includes a stage of heating the titanium containing material to such an extent that it is effective to increase the availability of at least one of the child radioisotopes for its subsequent removal. Radioactive isotopes can be thorium and/or uranium and/or one or more of the daughter radioisotope.

The heating temperature is preferably above 500oC. Actually found that in the first temperature range, for example between 500oC and 1000o232Th). In the second temperature range, such as 1000oC - 1300oC and especially at 1200oC or higher, the destruction of mother and daughter radioisotopes improving, and it happens to the same level, although even at higher temperatures, such as 1400oC, total destruction becomes high and remains the same destruction of mother and daughter radioisotopes, thus achieving a significant reduction in radioactivity.

Stage heating can be optimized for chemical or physical methods of removal, and it can be performed in an oxidizing or reducing atmosphere or in different in any relevant furnace or reactor. It should be noted that the optimum conditions of heat will depend on the subsequent stage of removal.

Found that the methods described in the claims Australia NN 14980/92 and 14981/92 are more effective for the removal of uranium and thorium from ilmenite than synthetic rutile. Also found that heat treatment of ilmenite in accordance with the invention makes uranium and thorium in the synthetic rutile product more susceptible to subsequent leaching.

Discovered that before the heat treatment thorium th microscopy with scanning). After heat treatment, the titanium containing material in accordance with the invention to a temperature of about 1200oC or higher phase rich in the content of thorium, with sizes up to a few microns, can be found on and under the surface of the titanium containing grains. The accumulation and concentration of thorium in discrete phases, marked as ilmenite and synthetic rutile, can allow for the physical (and chemical) separation phase with a high content of thorium from phases with a high titanium content, by an appropriate method, such as Attiki. However, the temperature required for optimum segregation phase with a high content of thorium, are higher than those required to make the isotope232Th and its daughter isotopes equally accessible to chemical methods of separation, for example by leaching.

Titanium containing material prepared by the removal of radioisotopes according to the above ways to simplify removal of radioisotopes, according to the invention may be further subjected to processing in accordance with the method described in one or both applications Australia NN 14980/92 and 14981/92, through leaching Mat is either processed only by the acid or acids. For example, leaching acid may be effective for dissolving phase, including radioisotopes and daughter radioisotopes, and, consequently, to extract the last of the titanium containing material. Thus, the above mentioned reagents can choose, among other things, on their solubility in acid, and in this respect are preferred borates. Effective acid for this purpose is hydrochloric acid, for example, at a concentration of about 1 M, but for practical reasons, the sulfuric acid may be preferred. If sulfuric acid is used for the primary leaching, it may be necessary secondary leaching with hydrochloric acid, preferably after washing, to retrieve the child radioisotope radium (228Ra). When used for this purpose secondary leaching, and not the primary leaching, radium can be removed, and hydrochloric acid can be recycled. Leaching of acid can be added fluoride, which can successfully get through fluoride reagent in the initial mixture of reactants. Effective fluoride reagents for this purpose include NaF and CaF.

The solid residue after leaching can then prometha radioisotopes. After this can be followed by drying or firing.

The closest in technical essence and the achieved effect is a method of processing zhelezotitanovanadievye material, is known from the article by E. P. Belyakova and other "Hydrochloric acid method of processing of ilmenite concentrates", Kiev, Naukova Dumka, 1971, S. 10 - 11.

The known method involves the reduction of iron contained in the titanium containing material, for example, such as ilmenite, largely to metallic iron in a reducing atmosphere in the furnace to obtain the recovered titanium containing material.

The furnace preferably has an elongated shape and rotatably. Then carry out the charging of such material, reducing agent, preferably powdered carbonaceous material such as coal, and one or more of the above reagents comprising one or more stekloobrazuyuschego compounds. In the furnace high temperature.

Then remove the mixture, which contains the recovered titanium containing material is subjected to acid leaching.

However, the above method has a low degree of extraction radiusname of the invention is also a task to develop a method of processing zhelezotitanovanadievye material, providing a higher degree of extraction of radioactive isotopes and daughter radioisotope from the specified material.

The problem is solved in that a method of processing titanium containing material comprising iron, such as ore, such as ilmenite, by reduction of iron in titanium containing material largely to metallic iron in a reducing atmosphere in the furnace, preferably in an elongated rotary kiln to obtain the so-called restored titanium containing material according to the invention includes the supply of titanium containing material, a reducing agent, preferably powdered carbonaceous material such as coal, and one or more of the described reagents and preferred one or more stekloobrazuyuschego compounds into the furnace, maintaining a high temperature in the furnace, removing the mixture, which includes the restored titanium containing material from the furnace through the exhaust hole according to the invention the removal of the titanium containing material for the removal of thorium and/or uranium and/or one or more subsidiaries of radioisotopes. Supported high temperature is predpochytaet one or more known stages:

1. Recovery in a rotary kiln iron oxide contained in the download ilmenite, mainly to metallic iron using coal as a heat source and reductant.

2. The cooled mixture is removed from the recovery furnace.

3. Physical separation drying restored ilmenite and residual charcoal.

4. Water oxidation (known as aeration) restored ilmenite for the conversion of metallic iron to iron oxide particles, which are separated from particles of a mineral with a high content of titanium dioxide.

5. Wet physical separation to remove iron oxide from the mineral particles with a high content of TiO2.

6. Possible stage acid leaching to remove part of the residual iron and manganese.

7. Washing, dewatering and drying of the synthetic rutile product.

Treatment for removal of thorium and/or uranium and/or one or more subsidiaries of radioisotopes can be successfully carried out after and/or during stage 4, and it can be done simultaneously with the stage 6 by acid leaching, preferably hydrochloric acid and predpochtitelnei acid can be followed by leaching with hydrochloric acid. For conventional acid leaching in the way of Bechara use liquor, typically H2SO4at a concentration of approximately 0.5 M

Or processing to remove thorium and/or uranium and/or one or more of their children radioisotopes can be done by substitution stage 4 acid leaching to remove metallic iron and radioisotopes in one stage. Again for this leaching prefer to apply the acid is HCl.

In another application of the mixture of the above-mentioned reagents, including one or more stekloobrazuyuschego compounds and possibly one or more glass modifiers, add in ilmenite and heated at 900 - 1200oC before processing method, which includes the main stages of the method of Bechara, as described, and then spend leaching to remove thorium and/or uranium and/or one or more of their children radioisotopes. Or heated ilmenite with added reagents can be leaching to remove thorium and/or uranium and/or one or more of their children radioisotopes to be processed by way of Becher.

Remove thorium and/or uranium and/or one or more of their children radioisotopes can also be achieved by treatment of the product of conventional si is more stekloobrazuyuschego compounds and possibly one or more glass modifiers, add in the synthetic rutile product and heated at 900 - 1200oC to leaching to remove thorium and/or uranium and/or one or more subsidiaries of radioisotopes.

The invention is additionally described and illustrated in the following non-limiting examples. In the examples specified value ThXRFrepresents the contents of the232Th in the material, as determined by x-ray fluorescence spectrometry (XRF), whereas the value of Th represents the value of the232Th calculated by measuring spectrometry 228Th in the sample, assuming that232Th and228Th are in secular equilibrium. When two isotopes of thorium are in secular equilibrium, then the values of ThXRFand Th are the same. When the value of ThXRFsignificantly less than the value Th, as noted in several of the presented examples, it means that the parent isotope232Th was removed to a more significant extent than child radioisotopes. When the examples do not specify a value Th, the quality of the measurements show that the activity of the sample is reduced to the same extent as the measured value ThXRF.

Analytical data 2">

Example 1. This example shows the effect of pre-treatment of ilmenite heating on subsequent removal of thorium from ilmenite leaching.

Samples of ilmenite Eneabba Nord (sample A) with the values of the quantitative analysis of ThXRFand Th equal to 375 and 355 frequent./million Th, respectively, were heated at temperatures 500, 750, 1000, 1100, 1200, 1300 and 1400oC in a muffle furnace for 2 or 16 hours.

Heated samples of ilmenite and the unheated sample of ilmenite was subjected to reaction with 2-molar sodium hydroxide solution at a solids content of 40 wt. % in a reactor equipped with a stirrer, rotating continuously at a speed of 750 rpm, thermowell containing a thermometer or thermocouple), and a counter-current condenser. The reactor was heated heating casing connected via a temperature controller with a thermocouple. Thus, the reaction mixture can be maintained at the required temperature. The mixture was heated at a temperature of 70oC for 1 hour. Then the solid residue was filtered, thoroughly washed with water and analyzed.

After that, the product is treated with caustic soda, returned to the reactor and subjected to leaching 6-molar hydrochloric acid containing 0.5 molar solution f which was intervali, thoroughly washed with water, dried and analyzed.

The results of the analysis of thorium in unheated and heated samples (sample A) after leaching with caustic soda and then with hydrochloric acid containing sodium fluoride, are presented in table. 1.

The results presented in table. 1, show that:

1. Good leaching232Th, but not228Th is effectively achieved at a temperature of 500oC and below.

2. At intermediate temperatures of 750 and 1100oC is achieved moderate leaching232Th, and also increases the amount of leachable228Th, however, the total percentage removal of thorium is less than in the heated sample.

3. At higher temperatures in the range of 1000-1300oC, especially at a temperature of 1200oC or higher is removed the same moderate amount232Th and228Th (i.e. the parent 232Th and daughter radioisotopes), and the total destruction of thorium increases with increasing temperature.

4. At a temperature of 1400oC reaches the total destruction of thorium, both232Th and228Th are removed to the same extent. Found that the radioactivity of the obtained product shows a significant effect of pre-treatment by heating to restore and aeration of ilmenite on disposal of thorium leaching obtained from ilmenite.

Samples of ilmenite from Eneabba Nord (sample A) was heated at temperatures of 750, 1000, 1200 and 1400oC in a muffle furnace for 2 or 16 hours. The heated samples were subjected to recovery with the use of charcoal (-2 + 0.5 mm) at a temperature of 1100oC in the terms established in the laboratory, to obtain a product similar to that obtained in the reducing furnace in the way of Becher.

The obtained restored ilmenite was aeronavali in the environment of ammonium chloride under conditions similar to those used in the method of Bechara, to remove metallic iron, and then it was videlacele hydrochloric acid containing sodium fluoride at a solids content of 25 wt.%, at a temperature of 90oC for 2 hours. In some cases, acid leaching was preceded by leaching through 2.5 M NaOH at a solids content of 25 wt.% at the 75oC for 1 hour.

In table. 2 results for heated and reduced samples were compared with the results for the sample which was heated to recovery. The results show that, when the temperature during the pre-processing heat increases, also increases the amount of thorium, the remote pose the oriy.

Example 3. Enhanced leaching of thorium and its daughter isotopes of synthetic rutile after heating synthetic rutile shown in this example.

Samples of standard synthetic rutile (SR) from the installation Narngulu (sample C) was heated in a muffle furnace at a temperature of 1000 - 1400oC for 16 hours. Then the heated samples of synthetic rutile was videlacele sodium hydroxide at 25 wt.% solid particles at the 75oC for 1 hour, followed by leaching with hydrochloric acid containing sodium fluoride at 25 wt. % at a temperature of 90oC for 2 hours. The results in table. 3 show that maternal Th and daughter radioisotopes are removed to a considerable extent from samples of synthetic rutile, when the temperature at which they were heated, increased.

Example 4. This example shows the effect of additive silicon dioxide individually and with other reagents in the ilmenite to heat treatment.

Samples of ilmenite (sample a) Eneabba Nord mixed with precipitated silicon dioxide and sodium fluoride or digitalmanuscript.com and heated in a muffle furnace at a temperature of 1000-1300owithin 1-2 hours. Subbytes heated sample was videlacele the Holy table. 4 results for processed, heated and leached samples were compared with the results for ilmenite, heated and leached, but without the addition of silicon dioxide or other reagents. The results show that the addition of only silicon dioxide had little effect after heating at a temperature of 1150oC, but that the addition of sodium fluoride is useful because the removal of thorium increased with increasing heating temperature. The results show that the activity is removed to the same extent to which thorium is removed.

In the additive phosphate with silicon dioxide is achieved better removal of thorium, and for this only requires a heating temperature of 1000oC.

Example 5. This example shows the effect of the additive phosphate compound to heat treatment.

A sample of ilmenite (sample A) of Eneabba Nord was mixed with analytical reagent (Anala R) - digitalmediastore or samples of commercially pure phosphate (1-5 wt.%), moistened with water, was mixed in a wet state is dried in a dryer at a temperature of 120oC and then heated in a muffle furnace at a temperature of 1000oC for 1 hour. Subbytes ilmenite treated with phosphate and n is C within 2 hours.

In table. 5 results for processed phosphate, heated and leached ilmenite compare with the results for ilmenite, which were heated and videlacele without the addition of phosphate to heat. The results show that the material treated with a phosphate is removed much more thorium. The results show that to achieve a similar degree of removal of thorium with less addition of reagent required acid increased strength.

Example 6. This example shows the effect of the additive only salt fluoride and other chemicals in the ilmenite to heat treatment.

In one of the two ilmenites Eneabba Nord (sample a or sample B) was added sodium or calcium fluoride alone or in combination with sodium carbonate, phosphate or boraxo. The samples were heated in a muffle furnace at a temperature of 1000 or 1150oC for 1 hour and was videlacele hydrochloric acid or hydrochloric acid containing sodium fluoride at a solids content of 25 wt.%, at a temperature of 90oC within 2 hours.

The results in table. 6 show that the addition of sodium fluoride alone or fluorides in combination with other reagents provides significantly greater removal of thorium during processing I.

Example 7. This example shows the additive effect of borate minerals in the ilmenite to heat treatment.

Natural bortovye minerals, particularly sodium borate (borax Na2B4O71OH2O), calcium-sodium borate (ulexite NaCaB5O98H2O) and calcium borate (colemanite, Ca2B6O115H2O), was added in the amount of 2-5 wt.% in the ilmenite Eneabba Nord (sample B) was heated in a muffle furnace at a temperature of 900-1100oC and videlacele hydrochloric acid or hydrochloric acid containing sodium fluoride, the amount of solid particles 25 wt.% at a temperature of 60 or 90oC within 2 hours.

In table. 7 the results of ilmenite, processed mineral borate, heated and leached, are compared with the results for the sample that was heated and videlacele without the addition of borate. The results show that good removal of thorium was achieved with the addition of boraxo and ulexite after heating at temperatures of 1000 and 1100oC, but when add the colemanite required heating temperature of 1100o. This is in line with the higher melting temperature of colemanite in comparison with boraxo and ulexite. The results also show that deletion is provided an additive effect of the mineral borate (borax or ulexite), and salts of calcium fluoride, hydroxide or sulfate) in ilmenite before heating.

Mineral borate, calcium salt (3-4 wt.% in the ratio of 1:1 or 2:1) was added into the ilmenite Eneabba Nord (sample) and heated in a muffle furnace at a temperature of 900-1100oC for 1 hour, and then videlacele hydrochloric acid or hydrochloric acid containing sodium fluoride in amount of 25 wt.% solid particles, at a temperature of 60 or 90oC within 2 hours.

The results in table. 8 show that good removal of thorium and activity was achieved especially when the temperature of 1000-1100oC. the Results also show that, when added calcium fluoride, it is possible to remove a large amount of thorium during acid leaching acid 0.25 M HCl with low power.

Example 9. This example shows the removal of thorium and uranium from the sample of ilmenite treated boraxo and calcium fluoride (fluorite), by leaching after heat treatment.

Samples of ilmenite Eneabba Nord (sample) mixed with boraxo and calcium fluoride (2-5 wt.% in the ratio of 1:1 or 2:1) and heated in a muffle furnace at a temperature of 1000oC or 1150oC for 1 hour, and then videlacele hydrochloric acid or hydrochloric acid containing fluoride cal is home, the thorium (as the parent232Th, as indicated by the value of ThXRFand subsidiaries228Th, as shown by the value Th), and uranium in ilmenite are removed by heat treatment and leaching. The results show that the amount of thorium and uranium increases with supplements boraxo and calcium fluoride at a temperature of 1000oC for 1 hour, and if the acid leaching of 0.25 M HCl. The higher the heating temperature of 1150oC and leaching with the use of highly concentrated acid (2 M HCl) enables the removal of large quantities of thorium and uranium.

Example 10. This example shows the effect of time of heating at a temperature on ilmenite treated boraxo and calcium fluoride (fluorite).

Samples of ilmenite Eneabba Nord (sample) mixed with boraxo and calcium fluoride (3 wt.% in ratio 1:1) was heated in a muffle furnace at a temperature of 1000oC for 0.25 to 4 hours and then was videlacele hydrochloric acid (0.25 M) at a solids content of 25 wt.% at a temperature of 60oC within 2 hours.

The results in table. 10 indicate that there is an optimum time during which the sample must be heated to remove naibolshee deleted activity. Heating for too long a time reduces the amount of thorium.

Example 11. This example shows the additive effect of borate minerals in the ilmenite to recovery.

A sample of ilmenite Eneabba Nord (sample a or sample B) was mixed with borate minerals (borax, ulexite or colemanite) or with mineral turnover (borax or ulexite) and calcium fluoride (fluorite), moistened with water, mixed in the wet state and added charcoal (-2, +0.5mm) in the silica crucible. The sample was heated in a muffle furnace at a temperature of 1000 or 1150oC for 1-4 hours for recovery of ilmenite and education restored ilmenite. Subbytes restored ilmenite was aeronavali for removing metallic iron and videlacele hydrochloric acid containing sodium fluoride in amount of 25 wt.% solid particles at a temperature of 60oC for 2 hours or worked directly with hydrochloric acid in the amount of 9.1 wt. % solids at a temperature of 60oC for 2 hours for dissolution of metallic iron, thorium and related activity.

In table. 11 results for samples treated with borate, restored and leached, spitali show that the addition of borate minerals leads to a significant removal of thorium. The results show that at a higher temperature recovery achieved higher removal of thorium during acid leaching. Rutile is in a more reduced state in the product at a temperature recovery 1150oC than at temperatures of 1100 recoveryoC.

Example 12. This example shows the additive effect of borate minerals in the ilmenite to restore coal as a solid reductant and the heating profile similar to the profile of the heat existing in the industrial recovery furnaces Bechara.

Samples of ilmenite Eneabba Nord (sample) mixed with borate minerals (borax, ulexite or colemanite) or boraxo plus calcium fluoride (fluorite), mixed with coal (-10 +5 mm) and placed in the cylinder. The cylinder is moved in a furnace, heated to a temperature of 1100 or 1150oC using heating profile, similar to that used in industrial regenerative furnaces Bechara, for a sample of recovered ilmenite of the same composition, which is produced in industrial plants. Restored ilmenite was aeronavali and above theC for 2 hours or videlacele hydrochloric acid directly when the solids content of 9.1 wt.% at a temperature of 60oC within 2 hours.

The results in table. 12 show that good removal of thorium is achieved boraxo and calcium fluoride and ulexite at a temperature recovery 1150oC, whereas with colemanite this is achieved at a temperature of 1100 recoveryoC. the Results show that along with the removal of the thorium is removed and the activity.

Example 13. This example shows the selective removal of thorium and then radium from ilmenite by acid leaching after recovery of ilmenite.

A sample of ilmenite Eneabba Nord (sample B), mixed with colemanite (3 wt. %), restored coal (-19 + 5 mm) in a rotary drum furnace at a temperature of 1100oC, it was used the heating profile industrial recovery furnaces Bechara, for a sample of recovered ilmenite, have the same composition, which is produced in industrial plants. Restored ilmenite was videlacele or hydrochloric acid at 9.1 wt.% solid particles at a temperature of 60oC for 2 hours, or aeronavali in the solution x is for 1 hour, and then hydrochloric acid at 25 wt.% solid particles at a temperature of 60oC for 1 hour.

The results in table. 13 show that the leaching restored ilmenite hydrochloric acid removes thorium (as the parent232Th and subsidiaries228Th) and uranium (child 228Ra). However, when using sulfuric acid and then hydrochloric acid, only the thorium is removed during leaching with sulfuric acid, and radium is removed in the subsequent leaching with hydrochloric acid.

Example 14. This example shows the removal of thorium and uranium from ilmenite, processed colemanite through leaching after it is restored to the restored ilmenite.

A sample of ilmenite Eneabba Nord (sample B), mixed with colemanite (3 wt. %), restored coal (-10 + 5 mm) in a rotating drum at a temperature of 1100oC, it was used the heating profile, similar to that used in industrial regenerative furnaces Bechara, for a sample of recovered ilmenite of the same composition, which is produced in industrial plants. Restored ilmenite or videlacele hydrochloric acid at 9.1 wt.% solid particles at a temperature of 60othe Institute of solid particles of 9.1 wt.% at a temperature of 60oC within 2 hours.

The results in table. 14 show that both thorium and uranium are removed during leaching with hydrochloric acid recovered ilmenite before or after aeration.

Example 15. This example shows the effect of pre-treatment by heating to restore to the removal of thorium during acid leaching.

Samples of ilmenite Eneabba Nord (sample B) was mixed with ulexite or colemanite (3 wt.%) and was heated at a temperature of 1000oC for 1 hour. The heated sample was cooled and then restored with the use of coal (-10 + 5 mm) in a rotating drum at a temperature of 1100oC by using a heating profile that is similar to the heating profile industrial recovery furnaces Bechara, for a sample of recovered ilmenite of the same composition, which is produced in industrial plants. Restored ilmenite was videlacele hydrochloric acid at 9.1 wt.% solid particles at a temperature of 60oC within 2 hours.

In table. 15 results for ilmenite, processed ulexite or colemanite, heated, reduced and leached, compared with results for samples recovered or heated and is selecive samples, processed ulexite or colemanite before heating.

Example 16

This example shows the additive effect of borate minerals in the ilmenite to recovery in an atmosphere of hydrogen and carbon dioxide.

Samples of ilmenite Eneabba Nord (sample A) was mixed with borate minerals (borax, ulexite or colemanite), was placed in a molybdenum boat and loaded inside a glass tube in the hot zone of the tube furnace. The sample was recovered at a temperature of 1100oC or 1150oC for 2 or 4 hours in the gas stream of a mixture of hydrogen and carbon monoxide such composition, in order to get the same oxygen partial pressure as in the reducing furnace Bechara (PH2/PCO2= 34,68). The obtained restored ilmenite was videlacele hydrochloric acid at 9.1 wt.% solid particles at a temperature of 60oC within 2 hours.

The results in table. 16 show that good removal of thorium was achieved during acid leaching in all cases.

Example 17. This example shows the removal of thorium from synthetic rutile obtained in the installation, after processing the mineral borate, heating leaching.

Samples of synthetic rutile from installation Aravali at a temperature of 1000 or 1150oC for 1 hour and then videlacele hydrochloric acid at 25 wt.% solid particles at a temperature of 60oC or 90oC within 2 hours.

The results in table. 17 for synthetic rutile from the plant treated with borate, heated and leached, compared with the results of synthetic rutile, leached or heated and leached without the addition of borate minerals. The results show that the thorium is removed from the synthetic rutile during acid leaching, when you add the borate minerals.

Example 18. This example shows the selective removal of thorium and then radium from synthetic rutile obtained in the installation, by acid leaching after heating.

A sample of synthetic rutile from installation to Marigoula (sample D) was mixed with ulexite (2 wt.%) and was heated at a temperature of 1100oC for 1 hour. Abbruzzi heated material was videlacele hydrochloric acid at 25 wt.% solid particles at a temperature of 60oC for 1 hour or sulfuric acid and then with hydrochloric acid at 25 wt.% solid particles at a temperature of 60oC for 1 hour.

The results in table. 18 show that the thorium and radium are removed, to the eat hydrochloric acid, thorium (parent 232Th and subsidiaries228Th) is removed in the first leaching, and radium (228Ra) is removed during the second leaching.

Example 19. This example shows the removal of thorium from different samples of ilmenite in Western Australia.

A sample of ilmenite from various deposits in Western Australia (samples E and F) were mixed with colemanite (5 wt.%) and restored coal (-10 + 5 mm) in a rotating drum at a temperature of 1100oC using heating profile, similar to that used in industrial regenerative furnaces Bechara, for a sample of recovered ilmenite of the same composition, which is achieved in industrial plants. Restored ilmenite was videlacele hydrochloric acid at 9.1 wt.% solid particles at a temperature of 60oC for 2 hours to remove thorium.

In table. 19 the results for the two samples with the additive and without the addition of colemanite, compared with the corresponding values for ilmenite, Eneabba Nord (sample B). The results show that thorium could be removed from other ilmenites as well as from the ilmenite Eneabba Nord.

Example 20. This example shows the removal of radium during ocalendar ilmenite Eneabba Nord (sample B) was mixed with colemanite and restored coal (-10 + 5 mm) in a rotating drum at a temperature of 1100oC using heating profile, similar to that used in industrial regenerative furnaces Becera to obtain restored ilmenite. The recovered oxidized ilmenite (Aeronavale), to remove metallic iron in a solution of ammonium chloride (1.2 wt.%) at a temperature of 80oC with the formation of air bubbles through the suspension (to saturate it with oxygen) for 16 hours.

The results in table. 20 for two oxidized and reduced samples of ilmenite, processed colemanite, compared with the results for the sample without treatment colemanite and with an initial sample of ilmenite. You can see that the levels of thorium and radium in the product is higher in the untreated sample in comparison with the original ilmenite due to the removal of iron during reduction and oxidation. Such can be seen that the product of ilmenite, which added a colemanite, thorium is concentrated to the same extent as in the sample without colemanite, but was removed a significant amount of radium.

Example 21. This example shows the additive effect of borate minerals in the ilmenite to recovery on removal of such impurities, such as silicon dioxide, PU glue is Anita Eneabba Nord (sample B) was mixed with borate minerals (borax, ulexite or colemanite) or boraxo plus calcium fluoride (fluorite), mixed with coal (-10 + 5 mm) and placed in the drum. The drum was rotated inside a furnace and heated to a temperature of 1100oC using heating profile, similar to that used in industrial regenerative furnaces Bechara, for a sample of recovered ilmenite of the same composition, which is produced in industrial plants. Restored ilmenite was videlacele hydrochloric acid at 9.1 wt.% at a temperature of 60oC within 2 hours.

The results in table. 21 show that good removal of impurities is achieved with a corresponding increase in the content of TiO2when ilmenite add the borate minerals to restore.

1. The way to simplify removal of radioisotopes such as uranium and thorium and/or one or more of their daughter radioisotope from a titanium containing material, characterized in that exercise contacting titanium containing material with one or more reagents at an elevated temperature selected to increase the availability of at least one of the child radioisotopes in titanium containing material, and select the reagent capable of forming phase with radioisotope and one or more subsidiaries of radioisotopes.

2. The method according to p. 1, characterized in that the reagent or reagents include one or more stekloobrazuyuschego reagents selected from the group stekloobrazuyuschego reagents, including borates, fluorides, phosphates and silicates.

3. The method according to p. 2, characterized in that stekloobraznoi reagent or reagents are selected from the group consisting of borates of alkali and alkaline earth metals.

4. The method according to p. 2, characterized in that stekloobraznoi reagent or reagents are selected from the group consisting of borates of calcium and sodium and calcinating borates.

5. The method according to p. 4, characterized in that stekloobraznoi reagent or reagents contains one or more from the group of Ca2B6O11, NaCaB5O9and Na2B4O4.

6. The method according to p. 5, characterized in that stekloobraznoi reagent or reagents contains one or more of the group of colemanite, ulexite and boraxo.

7. The method according to any of paragraphs.1-6, characterized in that the reagent or reagents include one or more glass modifiers.

8. The method according to p. 7, characterized in that as a modifier of fluorite glass is used.

9. The method according to any of paragraphs.1-8, characterized in that the eat, that increased temperature maintained within the range 1050-1200oC.

11. The method according to any of paragraphs.1-10, characterized in that the heated titanium containing material is converted into synthetic rutile, which is then leached to remove radioisotopes.

12. The method according to p. 11, characterized in that as a titanium containing material used ilmenite and that conversion involves the reduction of iron contained in it, to metallic iron and then water the oxidation of metallic iron to education detachable iron oxide.

13. The method according to p. 12, wherein the radioisotope is separated during the stage of oxidation.

14. The method according to any of paragraphs.1-10, characterized in that as a titanium containing material used synthetic rutile, obtained by processing of ilmenite, which includes the restoration of the iron contained in it, to metallic iron and then water the oxidation of metallic iron to form iron oxide for the Department.

15. The way to simplify removal of radioisotopes from a titanium containing material, characterized in that the implement stage heating titanium containing material to steps for subsequent removal.

16. The method according to p. 15, wherein the titanium containing material is heated to temperatures above 500oC.

17. The method according to p. 16, characterized in that the temperature is at least 1000oC.

18. The method according to p. 16, characterized in that the temperature is at least 1300oC.

19. The method according to any of paragraphs.15-18, characterized in that the heated titanium containing material is converted into synthetic rutile, which is then leached to remove radioisotopes.

20. The method according to p. 19, characterized in that as a titanium containing material used ilmenite, and transformation into rutile includes the restoration of the iron contained in it, to metallic iron for the formation of a detachable iron oxide.

21. The method according to any of paragraphs. 15-18, characterized in that as a titanium containing material used synthetic rutile obtained through processing of ilmenite, which includes the restoration of the iron contained in it, to metallic iron and then water the oxidation of metallic iron to the formation of the separated iron oxide.

22. The method of processing iron and titanium containing material, such ore as the lakes is in a reducing atmosphere in the furnace, preferably oblong in a rotary kiln to obtain the recovered titanium containing material, comprising loading into the furnace titanium containing material, a reducing agent, the extraction mixture, which contains the recovered titanium containing material from the furnace through the discharge opening and processing of the recovered titanium containing material, characterized in that the reducing agent used is preferably powdery carbonaceous material such as coal and furnace load one or more of the above reagents, which preferably include one or more stekloobrazuyuschego compounds, while maintaining high temperature in the furnace, however, the processing of the recovered titanium containing material is accompanied by the removal of thorium, and/or uranium and/or one or more subsidiaries of radioisotopes.

23. The method according to p. 22, wherein the elevated temperature is maintained within the range 900-1200oC.

24. The method according to p. 23, characterized in that the temperature of the support in the range 1050-1200oC.

25. The method according to PP.22, 23 or 24, characterized in that it further perform water oxidation of metallic iron for images is the property according to any one of paragraphs.22-25, characterized in that it further expose the treated titanium containing material acid leaching to remove radioisotopes.

27. The method according to p. 26, characterized in that as hydrochloric acid is used.

28. The method according to p. 26, characterized in that use sulfuric acid.

29. The method according to p. 26, characterized in that the leaching includes primary leaching with sulfuric acid and then the secondary leaching with hydrochloric acid.

Priority points:

31.07.92 - PP.15-17, and 19-21;

16.12.92 - PP. 1, 2, 6-14 and 22-27;

28.07.93 - PP. 3-5, 18, 28, and 29.

 

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FIELD: metallurgy; reworking wastes of alumina production process.

SUBSTANCE: proposed method includes preparation of batch of charge containing red mud and carbon reductant, heating the charge in melting unit to solid-phase iron reduction temperature, three-phase reduction of ferric oxides in charge by carbon reductant and saturation of iron with carbon in charge thus prepared, melting the reduced charge for obtaining metal phase in form of cast iron and slag phase in form of primary slag, separation of cast iron from primary slag in melt heated to temperature of 40 C, reduction of silicon and titanium from oxides contained in primary slag by aluminum and removal of cast iron and primary slag from melting unit; during preparation of charge, concentrate of titanomagnetite ore containing titanium oxide in the amount from 1 to 15% is added to red mud; besides that, additional amount of carbon reductant and additives are introduced; after separation of primary slag from cast iron in melting unit, cast iron is heated to 1500-1550 C and product containing ferric oxide is added to it; iron is reduced by carbon of cast iron for converting the cast iron into steel at obtaining secondary slag; main portion of steel is removed from melting unit, secondary slag is added to primary slag and silicon and titanium are converted into steel residue in melting unit by reduction with aluminum, thus obtaining final slag-saturated slag and master alloy containing iron, titanium and silicon; main portion of master alloy is removed from melting unit; after removal of final slag for converting the master alloy residue to steel in melting unit, titanium and silicon are converted into slag phase by oxidation and next portion of charge is fed to slag phase formed after converting the master alloy residue to steel. Proposed method ensures high efficiency due to obtaining iron-titanium silicon master alloy in form of independent product and production of alumina from high-alumina final slag or high-alumina cement and concentrate of rare-earth metals.

EFFECT: enhanced efficiency due to avoidance of intermediate remelting of steel.

10 cl, 2 dwg

FIELD: metallurgy of rare-earth metals; method of processing difficultly-stripped leucoxene concentrates of Yareg deposits.

SUBSTANCE: proposed method includes grinding crude concentrate and separating titanium- and silicon-containing fractions for obtaining rich titanium-containing concentrate. Ground initial concentrate is classified according to class 0.2 mm; product at size +0.2 mm is subjected to regrinding at additional separation of -0.2 mm fraction; -0.2 mm fractions are combined and are subjected to wet separation in field at magnetic induction of up to 0.1 T for separation of iron-containing fraction. Non-magnetic fraction thus obtained is subjected to dehydration and titanium- and silicon-containing fractions are separated by rough floatation obtaining froth product enriched with leucoxene and chamber product enriched with quartz; chamber product is dehydrated, ground and is subjected to check floatation for obtaining froth product enriched with leucoxene; froth product of check floatation is combined with froth product of rough floatation and is subjected to cleaner floatation for obtaining rich titanium-containing concentrate in froth product; chamber products of cleaner floatation at obtaining additional intermediate titanium-containing. Floatation at all stages is performed in acid medium with mixture of primary and secondary amines.

EFFECT: enhanced efficiency of separation of titanium- and silicon-containing concentrates; reduced power requirements; increased extraction of titanium-containing fractions.

4 cl, 1 ex

FIELD: inorganic compounds technologies.

SUBSTANCE: invention relates to technology of titanium-calcium mineral raw material, in particular to acid decomposition of sphene concentrate, and can be used to produce titanium dioxide and products based thereof. Prior to be treated with acid, concentrate is subjected to mechanical activation with energy supply intensity 10 kJ/s per 1 kg concentrate within 5 to 30 min. Mechanical activation in carbon dioxide medium is also possible at CO2 consumption 0.2-0,8 mole/mole CaO. For acid treatment of concentrate, 15-20% nitric acid is used at ambient temperature and atmospheric pressure, wherein additional titanium is transferred into solution. Resulting reaction mass is filtered to separate silica residue.

EFFECT: increased feasibility of process due to reduced acid treatment temperature and allowed atmospheric pressure.

2 cl, 5 ex

FIELD: nonferrous metallurgy; devices for purification of a spongy titanium.

SUBSTANCE: the invention is pertaining to the field of nonferrous metallurgy, in particular, to devices for purification of a spongy titanium. The technical result is an increase of productivity of the apparatus due to decrease of labor input for its servicing and acceleration of the process of a vacuum separation due to stabilization of a temperature mode in a retort-condenser. The apparatus contains a retort-reactor with a bottom branch-pipe and a false bottom closed by a cover with a central branch-pipe closed by a fusible stopper plug, a retort-condenser with a bottom branch-pipe with a stopper plug, a caisson with a distributor of water, a heated screen and with a fusible stopper plug. The apparatus in addition is supplied with a metallic nozzle mounted rigidly in the central branch-pipe of the cover under the fusible stopper plug and made in the form of a truncated cone with its smaller base facing a fusible stopper plug and with an inlet and outlet holes, a metallic shell mounted in the bottom branch-pipe of the retort-condenser and rigidly connected with the stopper plug, and with a sealed cover mounted rigidly in the upper part of the caisson. Under the sealed cover there are a bottom branch pipe of the retort-condenser and a water distributor.

EFFECT: the invention ensures increased productivity of the apparatus, decreased labor input for its servicing, acceleration of the vacuum separation process, stabilization of a temperature mode in the retort-condenser.

7 cl, 1 dwg

FIELD: methods of reprocessing of titanium-silicon raw materials.

SUBSTANCE: the invention is pertaining to methods of reprocessing of titanium-silicon raw materials and may be used for production of high quality goods on the basis of titanium. As a starting raw material use titanium-silicon product nitrogenous- fluoride decomposition of sphene concentrate and treat it with 80-85 % sulfuric acid. Titanium-silicon product has a structure (in mass %): 48.80-50.90 TiO2; 36.50-38.10SiO2; 1.78-1.85 CaO; 0.64-0.66Fe2O3; 0.23-0.24Al2O3; 0.50-0.52(T2O5 + Nb2O5); 0.020-0.021Ln2O3; 2.20-2.30 F; 5.41-9.33H2O. Sulfuric acid and titanium-silicon product are taken in the quantity meeting to the mass ratio ofH2SO4:TiO2 = l.5-l.6 : 1. The reaction mass is formed by its briquetting, heat it up to 150-160°C and hold at the temperature of heating. The conglomerated fragile porous cakes are cooled and leached by water with production of a titanium sulfate solution. The technical effect is an increased degree of extraction of titanium in the solution at a simultaneous raise of technological effectiveness of the method due to a decreased consumption of the acid, a decreased power input in the process and prevention of sintering of the reaction mass into a monolithic fusion cake. In addition the method improves the quality the produced titanium sulfate solution due to a decrease of the acid factor.

EFFECT: the invention ensures an increased extraction of titanium in the solution and improved the quality at a simultaneous raise of technological effectiveness of the method, decreased consumption of the acid and the power input, prevention of sintering of the reaction mass into a monolithic fusion cake.

3 cl, 1 tbl, 7 ex

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