Processing method of sulphide zinc products

FIELD: metallurgy.

SUBSTANCE: method includes oxidation zincsulfide in aqueous alkaline solution at presence of oxygen gas at temperatures 80-90C and regeneration of alkaline solution with usage of slaked lime with gypsum receiving. Additionally oxidation is implemented in aqueous solution of caustic soda with addition of cobalt sulphate with following filtration of solid oxidation product. Zinc extraction into solution is implemented by leaching of solid oxidation product.

EFFECT: oxidation rate increasing of sulphide and gypseous sludge utilisation, forming at solution regeneration.

1 tbl

 

The invention relates to the field of hydrometallurgical production of zinc and can be used for direct leaching of zinc from sulphide concentrates and middlings.

A method of refining sulfide zinc products include burning products, leaching the roasted material with extraction in a solution of zinc (see the book Shornikova A.P. Hydrometallurgy zinc. M, metallurgy, 1981, p.18).

The disadvantage of this method is the need for firing products with the utilization of sulfur-containing kiln gases, which requires large capital and operating costs.

A method of refining sulfide zinc middlings, including sulfuric acid leaching of zinc in the presence of ferric ions and crystallization of sulphate of iron (+2) from a solution from leaching, oxidation of iron and reuse its oxidized form and the zinc solution purification from impurities (ed. mon. 1530641 SW 19/22, publ. 23.12.89, bull. No. 47).

The disadvantage of this method is the high aggressiveness of solution used, in which the content of sulfuric acid is 250-430 g/l and a temperature of 90-100C, which leads to increased demands on the corrosion resistance of the equipment used.

Closest to the technical essence and dostigao the th result is a method for processing sulfide zinc products including the dissolution of sulphides of zinc in an alkaline medium in the presence of gaseous oxygen at temperatures of 80-90C (U.S. Pat. USA 4331635, publ. 25.05.82 MCI SW 15/10, SW 19/24 and U.S. Pat. U.S. No. 4153522 MCI SW 15/10, SW 19/24 (RJ metallurgy, 1980, GP).

The disadvantages of this method are the low reaction rate of the oxidation of sulphides, the high cost of the used reagent is ammonia and the difficulties of implementation of the gypsum slurry, forming after regeneration of ammoniacal alkaline solutions slaked lime.

The technical result of the present invention is to increase the degree of conversion of sulfur and the reaction rate of oxidation of sulfide zinc products, as well as the decision to recycle gypsum slurry through the production of gypsum, corresponding to GOST 125-79. This result is achieved in that in the method for processing sulfide zinc products, including the oxidation of zinc sulfide in aqueous alkaline solution in the presence of gaseous oxygen at temperatures of 80-90C, the extraction of zinc in the solution and regeneration of the alkaline solution with the use of hydrated lime to receive plaster, the oxidation is carried out in aqueous sodium hydroxide solution, with the addition of cobalt sulfate followed by filtration of the solid oxidation product, and the extraction of zinc in a solution of lead leaching solid product okiciyapi difference is the fact, that the addition of cobalt sulfate is 0.1-0.5% by weight zinc sulfide concentrate, and concentration of caustic soda in the solution is 3 to 10 g/L.

The method is as follows.

Sulfide zinc product composition, %: zinc 15-60, iron 5-30, sulfur sulfide 20-40, is loaded into a reaction chamber with an aqueous solution of caustic soda concentration of 3-10 g/l NaOH. The amount of zinc sulfide product in solution is 80-120 g/l In the same capacity metered cobalt sulphate in an amount of 0.1-0.5% by weight of the zinc product. The oxidant is gaseous oxygen (air or air enriched with technical oxygen, technical oxygen) served in a reaction chamber using dispergiruyushchei impeller. The processing temperature is maintained at 80-90C. the oxidation of zinc sulfide flows through reaction

After oxidation of the sulfide solid product containing the oxides of zinc and iron, ferrites, and the like, are filtered and processed by leaching in sulfuric acid with subsequent extraction of zinc from solution and solid products known hydrometallurgical processing method. The filtrate containing the sodium sulfate, is fed to the regeneration of alkali and receive gypsum sludge by treatment with ashenai lime. After drying the gypsum slurry receive plaster (GOST 125-79) and send it to cement plants. The regenerated alkaline solution used again in the process of oxidation of zinc sulfide product.

The proposed method is tested in laboratory conditions.

Tests have shown that the processing of sulfide zinc product by dissolving the zinc sulfide in aqueous caustic soda solution with a concentration of 3-10 g/l in the presence of gaseous oxygen at temperatures of 80-90C with the addition of cobalt sulfate in an amount of 0.1-0.5% by weight of zinc product can significantly improve the rate of oxidation of sulphides and after regeneration of caustic soda to obtain gypsum corresponding to GOST 125-79.

The limits of the additive amount of cobalt sulfate are associated with iron content in the zinc sulfide product. So, when the iron content in the range of 25-30% flow catalytic additives of strontium sulfate is reduced to 0.1% by weight of zinc product, and when the iron content of 5-10% of the consumption of cobalt sulfate is increased to 0.5% by weight of the zinc product. The limits of variation of concentration of caustic sodium in an aqueous solution of alkali provide the maximum yield of oxidized zinc with the solid product. So, when the alkali concentration is more than 10 g/l significantly increases the transition in the solution of the oxidized zinc, and when the concentration is AI less than 3 g/l starts to slow down the process of oxidation of sulphides.

Validation of the method is as follows.

100 g of zinc sulfide product composition, %: zinc 25,2, iron 23,4, sulfur 39,5, copper 0,85,lead 0,34, was dissolved in 1 l of aqueous solution of 5 g/l NaOH. The addition of cobalt sulfate amounted to 0.15% by weight of the zinc product. The process was carried out at a temperature of 85C. by using a dispersing device filed the air with technical oxygen. In similar conditions was tested by the known method. Oxidation of sulfides ran 20 hours. Then the solution was filtered. The filtrate was injected slaked lime in quantity - in terms of calcium - 50 g for the regeneration of the alkali and receive plaster. After filtering, drying and calcining at a temperature of 150C. the obtained semi-aquatic gypsum CaSO4 0,5H2O in the amount of 180 g that meets the requirements of GOST 125-79. In the known method the plaster according to GOST was not obtained from the partial transition him of ammonium ions and zinc.

The table below shows comparative data verification of known and proposed method of processing zinc sulfide product.

The name of the methodAdditive CoSO4, % by weight of zinc productT,The concentration of alkali in solution Duration, hoursThe oxidation state of S-2to SO4, %The content of Zn, mg/l in solution, alkaline solution of sodium sulfateNote
Offer0,1585NaOH2098,81,8Obtained according to GOST plaster
5 g/l
Known085NH4OH2051,410,5Not received
5 g/l

As can be seen from the obtained results, the use of the proposed method for processing sulfide zinc middlings the rate of oxidation of sulfide sulfur and completeness of oxidation increases with 51.4 to 98,8% in comparison with the known method. Solved the issue of recycling gypsum slurry by processing at its semi-aquatic plaster that meets the requirements of GOST.

1. JV is a method for processing sulfide zinc products including the oxidation of zinc sulfide in aqueous alkaline solution in the presence of gaseous oxygen at a temperature of 80-90C, the extraction of zinc in the solution and regeneration of the alkaline solution with the use of hydrated lime to receive plaster, characterized in that the oxidation is carried out in aqueous sodium hydroxide solution, with the addition of cobalt sulfate followed by filtration of the solid oxidation product, and the extraction of zinc in a solution of lead leaching of solid oxidation product.

2. The method according to claim 1, characterized in that the addition of cobalt sulfate is 0.1-0.5% by weight zinc sulfide product.

3. The method according to claim 1, characterized in that the concentration of caustic soda in aqueous solution is 3 to 10 g/L.



 

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1 tbl

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1 cl, 2 tbl

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4 cl, 1 tbl, 12 ex

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10 cl, 1 ex

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8 cl, 1 dwg, 1 ex

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2 cl, 2 ex

FIELD: hydro metallurgy.

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2 cl, 2 tbl

FIELD: separation and cleaning of metallic thallium, isotope-enriched thallium inclusive.

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EFFECT: possibility of obtaining degree of thallium purity of 99,9995% at minimum losses at all stages of chemical treatment.

2 cl, 5 ex

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