Method for processing of loparite concentrate

 

(57) Abstract:

The invention relates to the hydrometallurgical processing of ore concentrates, and more particularly to the processing of loparite concentrate. Method for processing of loparite concentrate is the grinding of the concentrate to the size of particles of at least 0.075 mm classification, the opening of loparite concentrate concentrated inorganic acid at atmospheric pressure, and subsequent separation of the extracted ingredients. For dissection, nitric acid with a concentration of 650 to 700 g/l, the process is conducted at 115-118C during continuous movement of the pulp through a number of series-connected reactor volumes. Obtained at autopsy concentrate hydrated cake oxides of refractory metals washed with water to obtain pure hydrate cake used for further processing, and the United nitrate solution of rare earth elements with impurities and activity, which is then neutralized with soda and subjected to decontamination, translating precipitated with ammonium sulfate and barium all impurities, including thorium, mesochori. After filtering pure nitrate solution of rare earth elem is blowing processing and disposal. Decontamination is carried out using ammonium sulfate and barium nitrate at 70-80C and pH 4.5 -5 for 6-8 hours Method allows us to simplify the process, improve the efficiency and the degree of extraction of tantalum and niobium. 1 C.p. f-crystals, 1 table.

The invention relates to the hydrometallurgical processing of ore concentrates, and more particularly to the processing of loparite concentrate.

Loparite concentrate is a complex raw material containing oxides of a large number of chemical elements. Used for processing of loparite concentrate brand CL-1 with the contents of loparite at least 95% in accordance with the applicable specifications contains, wt%:

The oxide of tantalum (Ta2O5) - 0,57

The oxide of niobium (Nb2O5) - 8,14

The titanium oxide (TiO2) of 38.1

The oxides of rare earth metals cerium group, mainly oxides of lanthanum (La2O3), cerium oxide (Ce2O3) oxide, praseodymium (Pr2O3), neodymium oxide (Nd2O3) - 32

The sodium oxide (Na2O) - 7,9-9,06

Calcium oxide (CaO) - 4,2-5,7

The strontium oxide (SrO) - 2,3-3,0

Iron oxide (Fe2O3) - 2,0-2,5

Silicon oxide (SiO2) - 1,95-2,5

Aluminum oxide (Alis CNIC alpha radiation

The thorium oxide (ThO2) - 0,54

From loparite concentrate extract the most valuable oxides of tantalum, niobium, titanium, and less valuable rare-earth metal oxides.

Up to the present time have been known and used two methods of processing of loparite concentrate, referred to as specialists of chloric and sulphuric acid technologies.

Processing of loparite concentrate the chlorination is more simple from a technological point of view (see A. N. Zelikman and other "metallurgy of rare metals), metallurgy, 1991, S. 95-100). Its essence is that loparite concentrate previously subjected to dry grinding and mixed with coke. The mixture is exposed to 100% drained gaseous chlorine at a temperature of 950-1050oC. differences in the volatility of the resulting chlorides components loparite concentrate allow you to split its main valuable components.

Chloride technology of processing of loparite extracts 93-94% of niobium and 86-88% of tantalum in technical oxides of 96.5-97% of the titanium in technical tetrachloride, removing the 95.5-96% of rare earth metals in the water chlorides.

However, chlorine technology is very dangerous and vrednota today it is absolutely not acceptable for use with the point of view of environmental safety.

Safer and the closest analogue of the claimed invention is a method for processing of loparite concentrate using concentrated sulfuric acid for the opening of loparite (see A. N. Zelikman and other "metallurgy of rare metals), metallurgy, 1991, S. 101, 103-105).

Sulphuric acid method is based on the decomposition of loparite concentrate with sulfuric acid and separating valuable components using differences in solubility of double sulfates of titanium, niobium and tantalum, rare earth elements with sulfates of alkali metals or ammonium. Source loparite concentrate is ground to a particle size of not less than 0.075 mm and subjected to classification. The opening of the concentrate is carried out using 95% sulfuric acid, spent based 2,78 t 1 t powdered concentrate. To prevent sintering of the reacting mass and improve recovery solution of niobium and tantalum to sulfuric acid is added ammonium sulfate (0.2 tons per 1 ton of concentrate). In the opening, occurring at a range of temperatures up to 270-280oC, niobium and tantalum in the presence of large quantities of titanium are part of the double sulfates of titanium in the form of isomorphic admixture. Rare earth elements entering - whaty spec subjected to water leaching. As a result, in the solid phase remain double sulphates REE, and in the liquid phase remains sulfuric acid solution of titanium, niobium and tantalum. In this activity, due to the presence of loparite source of alpha-emitting thorium Th, is divided between the solid and liquid phases by 50%. For the separation of titanium from niobium and tantalum using precipitation with ammonium sulfate insoluble titanium salt (NH4)2TiO(SO4)2H2O. In the sediment stands out 70-80% of the titanium content in the solution. Double sulfate of titanium is used as an effective tanning agent in the leather industry. Thermal him decomposition receive technical titanium dioxide. Remaining after separation of the titanium salt solution, referred to as the sulfuric acid mother liquor contains tantalum and niobium. This solution is subjected to fluorination 40% HF. Then for the extraction of tantalum and niobium in the process of the separation of extraction at 100% tributyl phosphate TBP. To enable subsequent extraction of rare earth metals conduct additional independent technological cycle of conversion of double sulfates of REE carbonates.

cnie products is about the same as with chlorine technology. In it for the opening of the concentrate is used in more environmentally friendly chemical reagent. However, this method has several significant disadvantages. The main of them is immediately at the first stage of processing - the showdown concentrate showdown and the release of the most valuable tantalum and niobium, go into solution, which spread among the less valuable components in the solid phase. As a result of this we have to separate from the most valuable components of the less valuable the double sulphate of REE, which takes in various forms up to 25-30% of tantalum and niobium. To return tantalum and niobium is necessary to carry out additional processing of the dump cake remaining after the processing of double sulphates REE. In addition, there irretrievable loss of tantalum and niobium with crystals of titanium salt when salting out from sulfuric acid solution of tantalum, niobium and titanium. In addition, the method is sequential, consisting of separate periodic stages that cannot be automatically combined into a single control circuit. All this makes the method complicated and expensive.

The present from the exercise of opening the concentrate was applied such inorganic chemical reagent and the process would go with such parameters, in the process of opening immediately provide complete separation of the components of the concentrate on the most valuable, less valuable components, as well as impurities and all of them would be in a form suitable for further processing, which provides a simplified way, increase its efficiency, but also increases the degree of extraction of the most valuable components of tantalum and niobium.

The problem is solved in that in the method for processing of loparite concentrate, including the grinding of the concentrate to the size of particles of at least 0.075 mm classification, opening loparite concentrate concentrated inorganic acid at atmospheric pressure and a temperature of more than 100oC, and subsequent separation of the recoverable ingredients, what's new is that for the opening of nitric acid with a concentration of 650 to 700 g/l, and the process is conducted at a temperature 115-118oC with continuous movement of the pulp through a number of series-connected reactor volumes obtained at autopsy concentrate hydrated cake oxides of refractory metals washed with water to obtain pure hydrate cake used for further processing, and United the ode and subjected to decontamination, translating precipitated with ammonium sulfate and barium all impurities, including thorium, mesochori, then filtered pure nitrate solution of rare earth elements used for further processing, and iron-thorium cake with all the impurities, subjected to subsequent processing and disposal.

Thanks to this solution at autopsy loparite concentrate under the influence of nitric acid to dissolve and pass into the nitric acid solution is all contained rare earth elements and impurities including radioactive thorium, mesochori. However, the most valuable component of the concentrate oxides of tantalum, niobium and titanium is absolutely not dissolved by nitric acid, and therefore completely 100% retained in the solid part, called cecom oxides of refractory metals (GCP). Subsequent exposure to water KEK easily completely washed from less valuable nitrates of rare-earth elements (REE) and impurities, fully transitioning in the United nitric acid solution. The washed cake with completely preserved oxides of refractory metals, almost not contaminated with radioactive impurities, is the starting product for later retrieval refractory meta whom I buried iron-thorium cake and net nitrate solution of rare earth elements. Net nitrate solution REE is the starting product for the subsequent extraction of rare earth elements. All this and provides a simplified way, increasing its efficiency and the complete preservation of the most valuable components of loparite.

The new method is that decontamination is carried out using ammonium sulfate and barium nitrate at 70-80oC and pH 4.5-5 for 6-8 hours

This solution provides the most simple simultaneous decontamination of the United nitrate solution and cleaned of impurities.

The inventive method of processing of loparite concentrate is carried out as follows. Source loparite concentrate is ground to a particle size at least 95% of particles of not more than 0.075 mm wet grinding with the classification of the particles and the thickening of the pulp loparite concentrate. Then carry out a nitric acid-based intrusion pulp loparite at atmospheric pressure nitric acid HNO3with concentration C=650-700 g/l at 115-118oC. In this temperature range at atmospheric pressure is provided by the opening under the influence of nitric acid of all particles loparite concentrate. During this interval of temperature maxima is e showdown at temperatures below 115oC will lead to incomplete opening of the particles loparite, and maintain process temperatures above 118oC impractical from an economic point of view and a sharp increase in the evaporation of the nitric acid. To increase the residence time of particles loparite in nitric acid and increase the likelihood of their opening processing is carried out in a so-called cascade option. This large volume is divided into a number of small volumes and consistently connect them. This increases the residence time of the particles in the reaction volume to a predetermined value, for example 40 hours, which reduces the removal of undiscovered particles from the reaction zone. After nitric acid-based intrusion receive the pulp opening - nitrate slurry of hydrated oxide oxides of refractory metals (GCP). In the opening in the solution passed all the oxides of rare earth metals lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide into soluble form nitrates of rare-earth elements R(NO3)3. At the same time in the process of opening under the influence of nitric acid in the solution is passed in the form of nitrates and all impurities loparite, including the source of the alpha-activity of the thorium oxide. The most valuable of allocated components laparostomy in the solid part of the slurry, becoming hydrated oxides of refractory metals - hydrate cake oxides of refractory metals. In the KEK these components are in the mixture, the same as they were in loparite. Thus, in the opening loparite concentrate nitric acid is full of single branch of the most valuable components (tantalum, niobium), remaining hydrated Keke without any losses from the less valuable components that have fallen into the solution. When hydrated, the cake is almost free from activity, since ~ 95% of thorium oxide is nitric acid solution of nitrates of rare-earth elements and impurities, and therefore, if further processing is not required, a special process of decontamination cake ELEVATION. Then nitrate hydrate slurry cake is diluted with water to 1.5-2.0 times and cooled to 40-50oC. After cooling are filtered solution of nitrate slurry of hydrated oxide and its subsequent washing from nitric acid solutions of nitrates of rare-earth elements and impurities. The radical difference of the proposed method from the prototype method is that in the present method hydrate cake containing the most valuable of the extracted components were washed off less valuable connective washing of the cake can be done in two series-connected pulse wash the columns with a nozzle of CRIMES, in which the cake is served at the top and water in a countercurrent him from the bottom of the column. In the hillshade get pure hydrated cake MARK in the form of a slurry with a concentration of nitrates NO3~ 2 g/l and the concentration of solid CTV=150-200 g/l of Pure hydrate cake is the starting product for the issuance of oxides of refractory metals, which, thanks to the present method completely left in him. The process of obtaining the oxides of tantalum and niobium from hydrate cake MARK is the subject of a separate patent application, and therefore is not considered here. In addition to pure cake after washing get United nitrate solution REE with all the impurities (Na, Ca, Sr, Fe, Si, Al, K, P) and activity (thorium Th, mesochori MsTh or what is the same, the isotope of radium Ra228). Then carry out decontamination nitrate solution REE, which is not difficult. For this first solution serves soda solution of Na2CO3for neutralization of nitric acid. Then served ammonium sulfate (NH4)2SO4and barium nitrate Ba(NO3)2that the result of the reaction between a form barium sulfate BaSO4precipitated. Mesochori has the same chemical properties with radium, nonretaliatory lattice. As a result, radium sulfate RaSO4is introduced into the crystal lattice of barium sulfate BaSO4and falls with him in the sediment. Neutralization along the way leads to the fact that thorium is present in the solution in the form of nitrate, forms an insoluble precipitate in accordance with reaction

Th(NO3)4+2Na2CO3+2H2O= Th(OH)4+4NaNO3+2CO2< / BR>
Simultaneously with the deactivation occurs the release of solution from impurities (Ca, Sr), which has wiselogel nitric acid. As a result of ash in the sediment fell in the form of hydroxide Fe(OH)3all ferric iron, resulting in a nitric acid environment. Under the influence of an excess of ammonium sulfate happened binding of calcium and strontium in soluble sulphate CaSO4, SrSO4also precipitated. The process of neutralization and decontamination is performed at a temperature of t=70-80oC and a pH of 4.5-5.0 for 6-8 hours.

Subsequent filtering of the solution to remove the iron-thorium cake containing all the activity, all the iron, calcium and strontium. Selected active iron-thorium cake is subjected to processing and subsequent disposal in the workings of the mine. Remaining in the filter clean nitrates is known to the specialists, and therefore is not considered here.

Njezavisimij the method is illustrated by the concrete example of its implementation.

Reworked the way the nitrate opening 1000 kg loparite concentrate brand CL-1 of the above structure.

The opening of the concentrate was carried out under the following conditions.

1. After the initial wet grinding concentrate > 95% of the particles have a particle size of not more than 0,074 mm

2. The solid content in the pulp opening - 600 g/L.

3. Initial concentration of nitric acid - 700 g/l

4. Temperature autopsy - 115-118oC.

5. Autopsy - 40 p.m.

6. Intensive mixing with a mechanical stirrer (speed n= 200-220 rpm).

At the opening of loparite concentrate was consumed.

1. Nitric acid 70% - 1440 kg

2. Technical water - 400 kg.

3. Heating steam (deaf ) - 550 kg.

4. Water for washing hydrate cake OTM - 3000 kg

In the nitrate processing reached the opening of loparite concentrate (total rare earth elements) - 95%.

Received the washed hydrate cake GCP - 575 kg (dry) of the following composition, %:
- 0,05

CaO - 0,4

Na2O - 0,75

Fe2O3- 0,35

SiO2- 3,5

NO3- 0,1

Also received 5430 l decontaminated solutions of nitrates of rare-earth elements the following composition, g/l:

The amount of oxides REE - 55

A solution of CaO - 4,0

The solution SrO - 1,5

The solution ThO2- < 0.003

MsTh (mesochori) - No

The output amounts of rare earth elements in the deactivated solution amounted to 93%. The resulting solution was evaporated to a concentration of 300-350 g/l for the sum of REE and apply for separate extraction of REE. In our example of the decontaminated solution were precipitated carbonates REE. On receipt of the deactivated REE carbonates were spent soda ash - 520 kg, nitrate barium - 6 kg, ammonium sulphate, 100 kg of process water for the preparation of solutions and flushing of sediment - 5000 kg, the heating steam (deaf) - 800 kg

Received carbonates of rare earth elements in the amount of R2(CO3)3with a humidity of 45% - 748 kg or 413 kg dry, containing 294 kg of REE oxides.

The advantages of the proposed method for processing of loparite concentrate compared with sulfuric acid method can be seen from the following data on the example of the workshop is given of specific embodiments of the claimed invention for any specialist in this field are obvious possibilities for its realization with the simultaneous solution of the set task. However it is also clear that the invention can be made small changes, but which will not exceed the scope of the invention defined by the following claims.

The inventive method of processing of loparite concentrate already at the initial stage of the opening provides a complete single branch of the most valuable components of tantalum, niobium and titanium, from less valuable rare earth elements and impurities. The most valuable components remain almost immediately clean from radioactivity. The obtained hydrated cake GCP and nitrates REE are suitable for further processing. The method is compared with the prototype significantly reduced number of technological operations, which form a continuous chain that permits them to be in continuous operation with full automation and control. This creates higher economic efficiency and profitability of the processing of loparite concentrate. The method creates a more gentle (less corrosive) conditions for operation of equipment due to lower temperatures and replacement of sulfate-fluoride environments on nitrate environment. Reduces costs and labor the tx2">

1. Method for processing of loparite concentrate, including the grinding of the concentrate to the size of particles of at least 0.075 mm classification, opening loparite concentrate concentrated inorganic acid at atmospheric pressure and a temperature of more than 100oWith further separation of the extracted ingredients, characterized in that the opening nitric acid with a concentration of 650 - 700 g/l, the process is conducted at 115 - 118oWith continuous movement of the pulp through a number of series-connected reactor volumes obtained at autopsy concentrate hydrated cake oxides of refractory metals washed with water to obtain pure hydrate cake used for further processing, and the United nitrate solution of rare earth elements with impurities and activity, which is then neutralized with soda and subjected to decontamination with translation precipitated with ammonium sulfate and nitrate barium all impurities, including thorium, mesochori, followed by obtaining a filtering net nitrate solution of rare earth elements used for further processing, and relettering cake with all the impurities, subjected to subsequent the singing of ammonium sulfate and barium nitrate at 70 - 80oC and pH 4.5 - 5 for 6 to 8 hours

 

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