Processing method of low-grade molybdenite concentrates
 Complex processing method of carbon-silicic black-shale ores / 2477327Invention refers to complex processing method of carbon-silicic black-shale ores, which contain vanadium, uranium, molybdenum and rare-earth elements. The above method involves ore crushing to the particle size of not more than 0.2 mm and two leaching stages. Oxidation sulphuric-acid leaching is performed at atmospheric pressure. Autoclave oxidation sulphuric-acid leaching is performed at the temperature of 130-150°C in presence of oxygen-containing gas and addition of a substance forming nitrogen oxide, as a catalyst of oxygen oxidation. Ion-exchange sorption of uranium, molybdenum, vanadium and rare-earth elements is performed from the obtained product solution. |
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Extraction method of molybdenum trioxide from tailings / 2475549 Method involves distillation of vapours of molybdenum trioxide in vacuum at residual pressure of 1-15 mm Hg and condensation of formed vapours of molybdenum trioxide. Besides, initial tailings are dissolved in molten boron oxide. Distillation of vapours is performed from molten metal at temperature of more than 1350°C, and condensation of vapours is performed at temperature of 800-820°C. |
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Processing method of waste molybdenum-aluminium-containing catalyst / 2466199 Method involves sintering of catalyst, leaching of sinter and deposition of aluminium at the first stage and molybdenum at the second stage from the solution. Catalyst is mixed with soda solution at solid-to-liquid ratio of 1:0.8÷1 prior to sintering. Soda consumption is taken based on 200-400 kg/t of raw material. The obtained sinter is subject to water leaching during 1-2 hours at temperature of 50-80°C. At that, molybdenum is deposited in the form of calcium molybdate at the second stage. |
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Method to extract copper and molybdenum from sulfide copper-molybdenum ores / 2463367 Method includes main floatation with several rewashes by sulphydric and apolar collectors to produce a collective crude copper-molybdenum concentrate. Then its treatment with a reagent is carried out, such as sodium sulphide, and selective floatation to produce a foamed molybdenum-containing product and a chamber copper-containing concentrate. When processing a crude copper-molybdenum concentrate, a combination of sodium sulfide and sodium thioantimonate at the ratio of 4:1÷1:1. |
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Method of molybdenum concentrate processing / 2441084 Concentrate is subjected to two-stage oxidising roasting. Note here that, before first stage, said concentrate is mixed with sulfur-binding additive to perform first roasting stage at 550-650°C for 15-30 min. Prior to second roasting stage, molybdenum concentrate is added to calcine produced at first stage in amount of 10-30 wt % from concentrate used in first roasting step. Second roasting is performed at 600-670°C for 30-40 min with subsequent leaching of molybdenum and rhenium from calcine obtained in first step. |
 Extraction of molybdenum from sulphide materials containing molybdenum by means of biological leaching in presence of iron / 2439178Method involves stages of (a) material interaction with acid leaching solution in presence at least of one iron compound and acidophilic microorganisms at least capable of oxidating ferrous iron, and (b) leaching. Leaching stage (b) is performed at control of molar ratio of dissolved ferric iron to dissolved molybdenum and it is assumed equal at least to 6:1, preferably at least to 7:1 and after leaching there performed is stage of (c) molybdenum extraction at least from one solid and liquid residue of the leaching process. Finally, molybdenum is extracted from leaching residue of leaching process. Final degree of Mo extraction from sulphide material containing molybdenum is 89%. |
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Procedure for production of high purity molybdenum for sputtering target / 2434959 Procedure consists in purification of solution of ammonia paramolybdate form impurities by ion exchange in neutral and sub-alkali mediums on hydrated oxide of tin and on sub-basic anionite AN-106. Further, ammonia paramolybdate is thermally decomposed at temperature 600-800°C to production of molybdenum oxide and is refined by zone sublimation at temperature 750-800°C in continuous flow of oxygen. Molybdenum oxide is heterogeneous reduced with hydrogen at temperature 700-750°C till production of powder of molybdenum. Powder is compressed to a rod which is subjected to electronic vacuum zone re-crystallisation till production of high purity molybdenum crystal. Molybdenum crystals are melt in electron vacuum in a flat crystalliser with melt of flat ingot of high purity molybdenum on each side at total depth not less, than twice. A molybdenum rod is treated with chlorine prior to zone re-crystallisation at rate of chlorine supply 100 ml/min and temperature 300°C during 1 hour. |
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Procedure for treatment of molybdenum concentrate (versions) / 2434066 According to the first version there is used preliminary mixed charge containing components at following ratio, wt %: molybdenum concentrate 69, reducer 31. Thermal treatment is carried out in a graphite can at temperature of combustion 1400-1600°C during 10-15 min. According to the second version there is used preliminary mixed charge containing components at following ratio, wt %: molybdenite concentrate 53-55, reducer 15-17, iron containing compounds 25-27, slag forming components 3-5. Thermal treatment is performed in the graphite can at temperature of combustion 2000-2200°C during 30-40 min. |
 Selective extraction of molybdenum (vi) from solutions of cations of heavy metals / 2428496Procedure for extraction of molybdenum (VI) from solutions of cations of heavy metals consists in sorption of molybdenum (VI) at value of pH of solution less, than value of pH of hydrolytic sedimentation of cations of heavy metals. As sorbent at sorption there is used activated bone coal. |
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Procedure for production of fine-dispersed powder of molybdenum / 2425900 Procedure for production of metal powder of molybdenum consists in reduction of molybdenum oxide (MoO3) with metal-reducer in melt of sodium chloride of potassium chloride or their mixture at ratio 1:1 at temperature 770-850°C. Upon reduction metal phase of molybdenum powder is separated from reaction mass. Reduction is performed with aluminium powder at ratio of source molybdenum oxide (MoO3) to melt equal to 1:3-5. |
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Processing method of micro production wastes of constant magnets / 2469116 Method involves oxidation of micro production wastes at temperature of 550-650°C in air atmosphere for destruction of crystal latitude Nd2Fe14B so that Fe2O3, Nd2O3, Fe2B is formed and moisture and oil is removed. Then, anhydrous fluorides of rare-earth metals are obtained and their metallothermic reduction is performed for production of constant magnets. After oxidation from oxidated microwastes is completed, rare-earth metals are leached with nitric acid with concentration of 1-2 mol/l at temperature of 20-80°C. Obtained nitrate solutions containing rare-earth metals and impurity elements are processed with solution of formic acid with extraction of formiates of rare-earth metals in the form of the deposit cleaned from impurity elements, which includes iron, aluminium, nickel, cobalt, copper and other transition metals. |
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Treatment method of sulphide concentrates containing precious metals / 2457263 Method involves leaching with further separation of non-soluble residue from the solution, its drying and further melting when it is mixed with sodium carbonate, silicon-containing flux, borax so that alloy of precious metals and slag is obtained. At that, original concentrate is subject to leaching by means of nitric acid solution. Melting is performed using the addition of sodium chloride to mixture. Concentrate is leached using nitric acid solution with mass concentration of 350-550 g/l. Sodium chloride is added to mixture for melting purpose in quantity which is more by 10-20% than stoichiometric quantity as per lead chloride obtaining reaction. |
 Method of processing natural uranium chemical concentrate / 2451761Invention relates to processing natural uranium chemical concentrate. Proposed method comprises concentrate leaching by nitric acid solution to obtain suspension, adding coagulant into suspension and suspension separation. Clarified solution is separated from residue and directed to extraction. Note here that polyacrylamide-based anion coagulant is used and suspension with said coagulant is subjected to permanent magnetic field effects. Coagulant concentration and duration of magnetic field effects are selected to ensure concentration of insoluble residue now exceeding 100 mg/l in clarified solution. In extraction from clarified solution, no antifloating emulsions are observed. |
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Method for obtaining dephosphorised concentrate of oolitic iron ores / 2449031 Invention refers to preparation of iron-ore raw material for metallurgical treatment by cleaning the latter from harmful impurities deteriorating the quality of obtained metals and alloys. Method for obtaining dephosphorised concentrate of oolitic iron ores involves high temperature treatment, cooling and leaching of concentrate with mineral acid. High temperature treatment of iron-bearing material is performed in the range of 1350-1450°C in reducing medium with participation of clinker minerals till molten metal and sinters are formed. They are cooled to magnetising roasting temperature of 750-860°C, crushed and separated with magnetic separation into clinker and concentrate. Then, concentrate is cooled to 50-90°C and supplied at that temperature for leaching with mineral acid for dilution of phosphorus. |
 Method of processing manganese-containing material / 2448175Method involves transfer of manganese and accompanying impurities into a solution through two-step treatment of the starting material with hydrochloric acid and absorption of chlorine with an alkaline solution. Further, impurities are separated to obtain a manganese salt solution which is then treated. The first step uses waste hydrochloric acid with concentration 1-10% with solid to liquid ratio equal to 1:(3-5). A manganese-containing residue is separated from the obtained pulp, where said residue is then treated at the second step with waste inhibited hydrochloric acid with concentration 20-24% and content of inhibitor of not less than 5 wt %, reaction with iron of which results in insoluble complex compounds, where said inhibitor is in form of quaternary ammonium salts, with molar ratio manganese:HCl=1.0:1.1. The insoluble residue of aluminosilicates is then separated and the manganese salt solution is then processed using existing methods. |
 Extraction of metals from sulphide minerals / 2448171Method has been elaborated for two-stage dilution of nickel in leaching acid. Suspension of mineral and acid is activated by oxidation. It is performed during T1 time by means of electrolysis or alternatively chemically, by adding for example of oxidating acid to mineral. After activation the suspension is exposed in oxygen-free conditions during T2 time. During T2 time much quicker dilution of sulphide begins; quick decomposition of sulphide gives the possibility to nickel to be diluted and thus leached from mineral. Diluted nickel is extracted from leaching acid for example by electrochemical extraction. |
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Method of processing chemical concentrate of natural uranium / 2447168 Method involves leaching the concentrate with aqueous nitric acid solution at high temperature to obtain a pulp consisting a solid and an aqueous phase. The aqueous phase is then separated by filtration from the solid phase in form of uranium nitrate solution. Uranium is then extracted from the nitrate solution using tributyl phosphate in a hydrocarbon solvent. The extract is washed and uranium is re-extracted. Leaching is carried out by adding nitric acid and water in an amount which enables to obtain a nitrate solution in the aqueous phase of the pulp, said nitrate solution containing dissolved silicon in concentration of 2.5-3.7 g/l. The solid phase, which consists of insoluble concentrate residues, is separated by filtration from the solution which contains dissolved silicon, uranium in concentration of 170-250 g/l and nitric acid in concentration of 80-120 g/l. Filtration is carried out not more than 24 hours after leaching, preferably not more than 5 hours after leaching. |
 Method of processing chemical concentrate of natural uranium / 2444576Method involves leaching in order to dissolve uranium when the concentrate reacts with nitric acid solution to obtain pulp from the concentrate. Uranium is then extracted from the pulp using tributyl phosphate in a hydrocarbon solvent. The extract is washed and uranium is re-extracted. Extraction is carried out from freshly prepared pulp which is obtained through direct-flow reaction at temperature 20-65°C of a stream of a suspension of the concentrate in water which is prepared beforehand and a stream of nitric acid solution with flow rate ratio which ensures nitric acid concentration in the pulp of 25-120 g/l. The period from the beginning of leaching to the beginning of extraction is not more than 10 minutes. |
 Method for obtaining cobalt and its compounds / 2444574Method for obtaining cobalt and its compounds involves conversion of cobalt from cobalt-bearing raw material to the solution; deposition of cobaltic hydroxide (III) using oxidiser and neutraliser, dilution of cobaltic hydroxide (III) with conversion of cobalt (III) to cobalt (II). Then, the obtained solution is cleaned from impurities and metallic cobalt or its compounds are obtained. Cobaltic hydroxide (III) is diluted with the participation of recovered reduced forms of iron and/or copper salts in the range of oxidation-reduction potential of 300-700 mV relative to silver-chloride comparison electrode and pH 1-3, thus adjusting the temperature of the process by means of evaporation cooling. Recovery of reduced forms of iron and/or copper is performed in a separate unit using the reducer. At insufficient amount of copper and iron in raw material supplied to the process there performed is cleaning of leaching solution from copper by cementation and recirculation of cleaning product to the recovery stage of reduced forms of iron and/or copper. |
 Manufacturing method of concentrate of precious metals from sulphide copper-nickel raw material / 2444573Method involves separation of Bessemer matte into metallised and sulphide fractions and oxidation leaching of metallised fraction with solution at the controlled chlorine supply. At that, ratio of sulphur and copper contained in metallised fraction is 0.3-0.7. Leaching is performed in the value range of oxidation-reduction potential of 430-470 mV, preferably 440-450 mV. Sludge of baths of electrolytic nickel refining of processing technology of sulphide Bessemer matte fraction is supplied together with metal faction of Bessemer matte for leaching. |
 Method for acid decomposition of calcium silicate and recovery of zirconium / 2244035Invention aims at recovering uncommon metals from silicate ores and concentrates in processing of zirconium concentrates. Method according to invention envisages treating cake obtained by caking zircon concentrate with calcium oxide in presence of nitric or sulfuric acid. Concentrated acid is added to water-slurried cake at constant speed during 30-60 min in two steps so that 18-25% of acid is added during first 30 min, whereupon zirconium is leached at 80-90оС. |
FIELD: metallurgy.
SUBSTANCE: method involves two-stage processing of concentrates with water solution of nitric acid, pulp filtration so that cake and molybdenum-containing solution is obtained. Then, calcium molybdate suitable for making of ferromolybdenum is deposited from the solution. Decomposition of concentrates is performed at addition to water solution of nitric acid, sulphuric acid in the quantity sufficient for retention of the whole molybdenum in the solution in composition of water-soluble sulphate compounds of molybdenyl, and namely with anionic complex [MoO2(SO4)2]2-.
EFFECT: creation of economic and environmentally safe technology allowing to process low-grade molybdenite concentrates as per a short scheme, which provides sufficient increase in throughout extraction of molybdenum and its associated metals from ores to commodity products, and thus, contributes to more rational use of mineral resources.
2 cl, 3 tbl, 2 ex
The invention relates to hydrometallurgy rare metals, particularly molybdenum, and may be used for processing low-grade molybdenum concentrates with obtaining calcium molybdate, suitable for smelting facilities.
There is a method of decomposition of molybdenum concentrates nitric acid at atmospheric pressure obtaining molybdenum acid, which is used either as a product or subjected to hydrometallurgical processing of obtaining as a commercial product paramolybdate ammonium or molybdenum trioxide (Angelican, Molybdenum. M., 1978. 440 S.).
The disadvantage of this method is that after decomposition concentrate 80% of the molybdenum is in the solid phase comprising molybdenum acid, and 20% molybdenum remains in the mother solution. Both of these products need hydrometallurgical processing, which leads to branching of the technological scheme, making it more costly and cumbersome. Another disadvantage is the selection of the formed nitrous gases in the atmosphere.
The known method autoclave decomposition of molybdenum concentrate nitric acid, obtaining molybdenum acid, which is used either as a product or subjected to hydrometallurgical processing of obtaining as a commercial product p is ramalingaiah ammonium or molybdenum trioxide (U.S. Pat. 3751555 (USA), 1973). The allocation of nitrous gases in the atmosphere is not happening, because they are directly in the autoclave regenerated nitric acid in the feed to the autoclave oxygen, which is, in fact, the only consumable reagent.
The disadvantage of this method is that after decomposition concentrate 80% of the molybdenum is in the solid phase comprising molybdenum acid, and 20% molybdenum remains in the mother solution. Both of these products need hydrometallurgical processing, which leads to branching of the technological scheme, making it costly and cumbersome. Another disadvantage is that the process is carried out in autoclaves devices requiring large capital operating costs and growing demands for safety.
The technical result of the proposed method is aimed at creating environmentally friendly azotnokislogo technology for processing low-grade molybdenum concentrates, providing translation of all molybdenum in solution, which allows to simplify the hydrometallurgical processing of products of decomposition of molybdenum concentrates, and obtaining as a final product of calcium molybdate, suitable for smelting facilities. In addition, if the concentrate of lead and silver method allows conc is to them in the cake.
The technical result is achieved by the fact that in the known method azotnokislogo decomposition of molybdenum concentrates at atmospheric pressure in the leaching solution in addition to nitric acid, add sulfuric acid, in a quantity sufficient to hold all of the molybdenum in solution in the composition of water-soluble sulfate compounds molybdenite, and obtained after filtration of the slurry solutions of molybdate precipitated calcium by the addition of calcium chloride during the adjustment of the pH with alkali.
Formed during decomposition concentrate oxides of nitrogen capture by absorption of water from the regeneration solution of nitric acid, which is directed to attackone decomposition concentrate.
In addition, the original pre-concentrate is subjected to a "dry" mechanical activation, after which when further processed by astrocytoma method lead and silver are concentrated in the cake.
The essence of the proposed method lies in the fact that the decomposition of low-grade molybdenum concentrates leaching solution containing in addition to nitric acid, sulfuric acid, all molybdenum goes into solution due to the formation of water soluble sulfo-molybdosilicic connections and change as a consequence of the mechanism of decomposition.
In the known methods azotnokislogo decomposition of molybd nicovich concentrates the main end product is molybdenum acid, formed by the reaction (I)
In the initial period of time the whole of the oxidized molybdenum goes into solution, where is the composition of cations MoO22+and Mo2O52+. With the increase in solution concentration of sulphuric acid portion of the molybdenum binds to anionic sulfate complexes (e.g., [MoO2(SO4)2]2-). A further increase in the solution concentration of molybdenum in the lack of sulfate ions leads to coagulation of H2MoO4(TV). In industrial practice, 80% molybdenum precipitates in the composition of the molybdenum acid, and 20% remains in the mother solution comprising anionic complexes.
Feature low-grade molybdenum concentrates is that they contain a large number of related molybdenite sulphide, which reacts with nitric acid according to the reactions (2-5)
However, according to reactions (4,5) allocated monoxide nitrogen, which oxidizes molybdenite, and reactions (2, 4) is allocated an additional amount of sulfuric acid. Attackone leaching of molybdenite in this case is described by reaction (6)
So what Braz, in the leaching of molybdenum concentrates is the following dynamic equilibrium between the original molybdenite and products of its oxidation:
Adding to the slurry of sulfuric acid increases the concentration of sulfate ions in the solution and the equilibrium is shifted towards the formation of anionic complexes ([MoO2(SO4)2]2-), which allows to keep the molybdenum in solution, and also to shift the equilibrium of reaction (6) to the right by removal of the primary reaction product in sulfate complex and thereby increase the recovery of molybdenum in solution.
Example 1. As a source of raw material used low-grade molybdenum concentrate of the following composition (wt.%): MoS2- 29,2; FeS2- 26,9; PbS - 5,6, CuFeS2- 10,0; ZnS - 4,0, Ag - 336 g/T. the Concentrate was subjected to two-stage astrocytoma the decomposition of a solution containing 350 g/l of nitric acid and 200 g/l of sulfuric acid at a temperature of 85°C, the ratio of T:W=1:4, duration 2 h at each stage and the atmospheric pressure in the reactor, the agitator with mechanical stirring. Table 1 shows the material balance for molybdenum in the above-mentioned process parameters.
| Table 1 | |||
| The material balance for molybdenum (t=85°C T:W=1:4, τ=2 h on each stage, [HNO3]=350 g/l, [H2SO4]=200 g/l). | |||
| Name of product | The molybdenum content | ||
| Mass, g Volume, ml |
The concentration of Mo, g/l; % | Weight of molybdenum, g | Mo, % of baseline |
| The original concentrate | 10,0 | 16,8 | 1,680 | 100,00 |
| The solution from the first stage leach with promodag | 71 | 14,08 | 1,000 | 59,52 |
| The solution from the second stage leach with promodag | 59 | 10,97 | 0,647 | 38,49 |
| TOTAL solution | - | - | 1,647 | 98,01 |
| Conveyor cake | 4,22 | 0,72 | 1,79 |
| TOTAL | - | - | 1,677 | 99,80 |
| The discrepancy of | - | - | 0,003 | 0,20 |
The resulting slurry was filtered and the filtrate was besieged molybdate calcium in the following way. In the original solution slowly with vigorous stirring was added lime in an amount necessary to neutralize the solution to pH=3.
Most of the sulfate ions bound in plaster, which is separated by filtration. The filtrate on gosaiganj sulfate ions with a solution of barium chloride and re-filtering. In cleared sulfate ions solution add CaCl2as part of a 40%aqueous solution in a stoichiometric amount to react with molybdate ions, is heated to a temperature of 80-90°C and neutralized with caustic soda to pH=7,0-7,5, when this precipitate hydroxides. Then the pulp after filtration, neutralized to pH=8,5-9,0, cooled to room temperature and filtered. Under such conditions, the molybdenum is deposited in the structure of the molybdate calcium at 94-95%.
The quality of the resulting CaMoO4(table 2) corresponds to the brand of MDK-2, containing not less than 40% of Mo (co is the actual content of the impurities is not more %: R - 0,2; S - 0,23).
| Table 2 | ||
| The quality of the resulting CaMoO4 | ||
| The content of the main components, % | ||
| Mo | CA | S | P |
| 41,8 | 23 | 0,21 | 0,05 |
The formed nitrous gases caught in the columns of the absorbers with the formation of nitric acid.
Example 2. As a source of raw material used low-grade molybdenum concentrate of the following composition (wt.%): MoS2- 29,2; FeS2- 26,9; PbS - 5,6, CuFeS2- 10,0; ZnS - 4,0, Ag - 336 g/T. the Concentrate was subjected to mechanical activation in a centrifugal planetary mill LIAA - 015 when you factor energonapryazhennosti - 25 g. The duration of activation of 3 min, weight of the concentrate 20 g, weight of steel grinding bodies - 800, Mode of activation of the air. After activating concentrate to determine changes in the reactivity of molybdenum and related metals subjected astrocytoma the decomposition of a solution containing 350 g/l of nitric acid and 200 g/l of sulfuric acid at a temperature of 0°C, the ratio of T:W=1:4, duration 30 min and atmospheric pressure in the reactor, the agitator with mechanical stirring. Table 3 shows the results of experiments.
| Table 3 | ||||
| Effect of mechanical activation on the extraction of molybdenum and related elements in the solution with nitric-sulfuric acid leaching of molybdenum concentrate (t=80°C, τ=30 min, T:W=1:4, n=350 rpm, [HNO3]=350 g/l, [H2SO4]=200 g/l) | ||||
| ELEH- ment |
The content in concentrate, % | Preliminary mechanical activation concentrate | ||
| No | Yes | No | Yes | |
| Concentration in the solution after leaching, g/l (for Ag, Pb and As mg/l) | Extraction into solution, % | |||
| Mo | 16,5 | 6,44 | 13,2 | 44,49 | 83,2 |
| Cu | 2,25 | 1,18 | 2,05 | 59,79 | 94,76 |
| Ag | 0,0336 | 0,24 | 0,13 | 0,82 | 0,40 |
| Fe | 13,00 | 10,07 | 12,04 | 88,31 | 96,32 |
| Zn | 1,60 | 1,19 | the 1.44 | 84,79 | 93,60 |
| Pb | scored 8.38 | 98,4 | 44,0 | of 1.34 | 0,55 |
| As | 0,0819 | 42,9 | 56,1 | 59,79 | 71,06 |
You can see that the leaching pre-activated concentrate increases the extraction solution all concentrated in the leaching in the liquid phase elements. Removing the same in a solution of lead and silver is reduced, thereby increasing the concentration of these metals in the cake is.
Thus, the implementation of the claimed method allows to simplify the processing of low-grade molybdenum concentrates, get calcium molybdate, corresponding brand MDK-2, suitable for production of ferromolybdenum, to concentrate the lead and silver in cake and exclude the allocation of nitrous gases in the atmosphere. In addition, the transfer molybdenum sub-sector of non-ferrous metallurgy in low-grade concentrates will provide a more rational use of natural resources by reducing losses during flotation (exceptions are numerous finishing operations with the purpose of receiving the certified concentrates).
1. The way azotnokislogo decomposition of low-grade molybdenum concentrates, including two-stage processing of concentrates aqueous solution of nitric acid, filtering the slurry to obtain a cake and a solution containing molybdenum, and precipitation from a solution of calcium molybdate, suitable for production of ferromolybdenum, characterized in that the decomposition of lead concentrates adding an aqueous solution of nitric acid and sulfuric acid in a quantity sufficient to hold all of the molybdenum in solution in the composition of water-soluble sulfate compounds molybdenite, in particular with the anionic complex [MoO2(SO4)2]2-.
2. The method according to claim 1, characterized in that the source is oncentrate previously subjected to a dry mechanical activation for preconcentration of lead and silver in cake which technogenic raw materials for their retrieval.