The method of hydrometallurgical processing of tungsten concentrates
(57) Abstract:The invention relates to hydrometallurgy refractory metals. In this way the cleaning solution of sodium tungstate from impurities lead by exposure of the solution after neutralization to pH 8 - 9 for 2 h at 90°C, cooling down to 40 - 50°C, the introduction of salts MD and defend. Tungsten is recovered from the purified solution by sorption. Desorption of tungsten with the anion exchange resin is performed with the ammonia solution. The anion exchange resin after desorption is first washed with water, then treated with salt-containing filtrate sorption. Water after washing of the anion exchange resin is used again when desorption of tungsten. The method allows to increase the degree of purification from impurities, to increase the output of tungsten. The inventive method relates to a hydrometallurgical rare metal, in particular tungsten. Most effectively the inventive method can be used to obtain pure compounds of tungsten from conforming wolframite concentrates.Known methods soda and sulfuric autoclave decomposition of tungsten raw material /1/. These methods are characterized by a high consumption of chemicals and water, low extraction of tungsten in the finished product is acidic solutions and slurries by sorption using different ion with subsequent desorption of ammonia solutions /2/. The disadvantage of this method is the low degree of extraction of tungsten, low efficiency of the process of regeneration of the ion exchanger, and increased consumption of reagents.The closest in technical essence and the achieved result of the claimed method is a method of processing wolframite concentrates, including grinding of the product, leaching of tungsten solutions of sodium hydroxide at a temperature of multistage cleaning solutions from impurities, the sorption cleaners and crystallization of parabolicamara ammonium /3/. By this method a cleanup productive tungsten-containing solutions from silicon carried out using the process of thermal hydrolysis pre neutralize the excess alkalinity of the mineral acid to pH 7 to 9 and keeping the system within 48 hours of the Filtered solution at room temperature is supplied to the cleaning of impurities of arsenic and phosphorus by treatment of a solution of compounds of magnesium and within two hours the ion exchanger after desorption of tungsten is treated with a solution of sulfuric acid with a concentration of 30 to 50 g/l, followed by washing with water until pH 2 to 4 for the purpose of moving the ion exchange resin in the sulfate form and provide conditions for the sorption of tungsten in the water, low degree of purification from impurities, insufficient output of tungsten into finished products, as well as a significant duration of the process.The technical result is to eliminate these drawbacks, namely improving the degree of purification from impurities, increase the yield of tungsten and improving the performance of the process.This technical result is achieved in that in the method of hydrometallurgical processing of tungsten concentrates, including grinding of the concentrate, leaching of tungsten solution of sodium hydroxide under heating, neutralize excess alkalinity to pH 8 to 9, the purification of the resulting solution of sodium tungstate from silicon, arsenic, and phosphorus with the use of magnesium compounds, sorption of tungsten on the anion exchange resin, the desorption of tungsten solution of ammonia with subsequent regeneration of the resin and the crystallization of parabolicamara ammonium from decorate, according to the invention, the cleaning solution of sodium tungstate from impurities lead by exposure of the solution after neutralization for 2 h at 90oC, cooling down to 40 - 50oC, the introduction of magnesium salts and sedimentation, and the regeneration of the resin after desorption of tungsten lead in two stages: in the first ion exchanger treatment is terrasim the filtrate sorption.The essence of the method is that the cleaning solution of sodium tungstate from impurities is carried out by neutralizing the solution to pH 8 - 9, extracts for 2 h at a temperature of 90oC, the cooling system up to 40 - 50oC and the introduction of magnesium salts in amounts of 3 to 6 moles per one mole of the amount of phosphorus and arsenic, and after desorption regeneration of the ion exchanger with a translation of it in the salt form are in two stages: in the first ion exchanger is treated with water using prambody for the preparation of regenerating solution to the second - salt-containing filtrate sorption excessive concentration of mineral acid.Cleanup operations from compounds of silicon thermohydrolysis and from arsenic and phosphorus is carried out in one reaction zone. Maintaining excess alkalinity below pH 9 is necessary for maximum coagulation of silica compounds and is optimal for the formation of insoluble magnesium compounds arsenic and phosphorus. The lower bound pH 8 is determined by the need to prevent loss of polivalente ammonium neutralising solutions, which leads to the reduction of tungsten into finished products and reduce the degree of extraction of tungsten from the source of raw materials.This method allows to reduce the consumption of reagents and water, to increase the degree of purification solutions from impurities, increase the output of tungsten in the finished product and to reduce the duration of the process that determines the reduction of energy consumption.The method is implemented as follows.Example
Wolframite concentrate containing 48% tungsten, crushed to size class 90% to 30 μm, was admitted to the leaching of the sodium hydroxide solution with a concentration of 200 g/l when the ratio of the weight of the product to the volume of leach solution, equal to 1:4 at a temperature of 105oC for 3 hours After leaching of tungsten content in the solution obtained 121 g/l, washed the cake contains 2.7% tungsten. For cleaning tungsten-containing solution from the impurities of silicon, arsenic and phosphorus used combined treatment process, including by up to a temperature of 45oC and the introduction of a salt of magnesium chloride in the amount of 6 moles to one mole of the amount of arsenic and phosphorus. After settling in for 48 h and then filtering the precipitate, the solution after neutralization to pH 3 to 3.5 was sent on the sorption of tungsten on the ampholyte EAP-14K. The capacity of the saturated ion exchanger for tungsten amounted to 38% when the content of tungsten in the filtrate sorption 0,028 g/L. After washing the saturated ion exchange resin from the spent sodium desorption of tungsten solution of ammonium hydroxide. After desorption of tungsten Ippolit regenerates translated it in sulfate form in two stages. In the first stage, the resin was treated with water using wash water for cooking Stripping solution, the second stage - salt-containing filtrate sorption within 3 hoursAfter evaporation of the commodity fraction of decorate spent crystallization of parabolicamara ammonium, which satisfied the requirements of the relevant SPECIFICATIONS.As a result of experiments, it was found that the combination of cleansing operations reduces the duration of the whole process for 2 h, which in turn leads to reduced energy consumption and to decrease the content of impurities in purified Rast is monia due to the return of wash water from the first stage of regeneration of the ion exchanger to 10% of the specific technological consumption of ammonia per unit of tungsten products and the elimination of the consumption of mineral acid to neutralize the excess of ammonium hydroxide, coming from the ion exchanger with stage desorption of tungsten. Processing of the resin salt-containing filtrate sorption excessive concentration of mineral acid prevents the consumption of an additional amount of acid at the stage of regeneration and eliminates water consumption for the operation of washing the ion exchanger from excessive acidity up to 6 to 8 volumes on the volume of the incoming ion exchanger, and also provides increased output of tungsten into finished products by 0.8 to 1.2%. An additional advantage is the reduction of neutralizing agent (soda lime) on the operation of neutralization of waste effluents sorption before disposal.Thus the implementation of the claimed method allows for reduced consumption of reagents and water, high degree of purification from impurities, increase the yield of tungsten into finished products and reduce the duration of the process.Literature:
1. A. N. Zelikman and other metallurgy of rare metals), metallurgy, 1978, page 37
2. USSR author's certificate N 1029631, 1981, C 22 B 34/34, C 22 B 34/36.3. A. N. Zelikman metallurgy of refractory rare metals), metallurgy, 1986, pp. 52 - 66. The way hydrometallurgical processing wolframowych heating, neutralize excess alkalinity to pH 8 to 9, the purification of the resulting solution of sodium tungstate from silicon, arsenic, and phosphorus with the use of magnesium compounds, sorption of tungsten on the anion exchange resin, the desorption of tungsten solution of ammonia with subsequent regeneration of the resin and the crystallization of parabolicamara ammonium from decorate, characterized in that the cleaning solution of sodium tungstate from impurities lead by exposure of the solution after neutralization for 2 h at 90oC, cooling down to 40 - 50oC, the introduction of Mg salts and sedimentation, and the regeneration of the resin after desorption of tungsten lead in two stages: in the first ion exchanger is treated with water followed by use of wash water at the stage of desorption of tungsten, and the second - salt-containing filtrate sorption.
FIELD: rare, dispersed and radioactive metal metallurgy, in particular hydrometallurgy.
SUBSTANCE: invention relates to method for reprocessing of polymetal, multicomponent, thorium-containing radwastes, formed when reprocessing of various mineral, containing rare-earth elements, Nb, Ta, To, V, Zr, Hf, W, U, etc. Method includes treatment of solution and/or slurry with alkaline agent; introducing of sulfate-containing inorganic compound solution and barium chloride; treatment of obtained hydrate-sulfate slurry with iron chloride-containing solution, and separation of radioactive precipitate from solution by filtration. As alkali agent magnesia milk containing 50-200 g/dm2 of MgO is used; treatment is carried out up to pH 8-10; sodium sulfate in amount of 6-9 g Na2SO4/dm2 is introduced as solution of sulfate-containing inorganic compound; barium chloride solution is introduced in slurry in amount of 1.5-3 g BaCl2/dm2. Hydrate-sulfate slurry is treated with solution and/or slurry containing 0.8-16 Fe3+/dm2 (as referred to startingsolution) of iron chloride, followed by treatment with high molecular flocculating agent and holding without agitation for 0.5-2 h. Radioactive precipitate is separated from mother liquor, washed with water in volume ratio of 0.5-2:1; then washed with sodium chloride-containing solution and/or slurry in volume ratio of 0.5-2:1; radioactive precipitate is removed from filter and mixed with mineral oxides in amount of 0.5-0.8 kg MgO to 1 kg of precipitate. Formed pasty composition is fed in forms and/or lingots and presses with simultaneous heating up to 80-1200C.
EFFECT: filtrate with reduced radioactivity due to increased codeposition coefficient of natural Th-232-group radioactive nuclide, in particular Ra-224 and Ra-228, with radioactive precipitates.
10 cl, 1 ex