Is it possible to get gold from pyrite?

Publication number RU2034062C1 RU2034062C1 SU5040554A RU2034062C1 RU 2034062 C1 RU2034062 C1 RU 2034062C1 SU 5040554 A SU5040554 A SU 5040554A RU 2034062 C1 2034062 C1 RU 2034062C1 Authority RU Russia Prior art keywords pyrite cinder gold silver extraction Prior art date 1992-04-29 Application number Other languages English (en) Inventor I.P. Smirnov L.I. Divers G.F. Ivanov G.I. Moskvicheva Yu.A. Menshikov M.A. Zhilichev N.V. Gritsenko V.I. Yasenkov T.D. Chukhlebova E.M. Shklyar A.P. Yakovlev Ya.V. Stoller V.F. Bludenov V.A. Nerlov V.F. Devbilov Original Assignee All-Russian Research Institute of Chemical Technology Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.) 1992-04 -29 Filing date 1992-04-29 Publication date 1995-04-30 1992-04-29 Application filed by All-Russian Research Institute of Chemical Technology filed Critical All-Russian Research Institute of Chemical Technology 1992-04-29 Priority to SU5040554 priority Critical patent/RU2034062C1/ru 1995-04-30 Application granted granted Critical 1995-04-30 Publication of RU2034062C1 publication Critical patent/RU2034062C1/ru

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Abstract

Use: concerns the extraction of gold and silver from pyrite cinders obtained by firing iron pyrite (pyrite) and which is a waste of sulfuric acid production. Essence: sorption extraction of gold and silver from cinder pulps is carried out. The cinder is subjected to acid treatment, after which the liquid phase is separated, copper and zinc are extracted, the solid phase is further ground in the presence of lime, aeration is carried out at elevated temperatures and pressure, and then cyanidated in the presence of a sorbent. When processing cinders using the proposed method, it is possible to significantly increase the extraction of precious metals by 20 – 30%, thus, from each ton of cinder, which is a production waste, more than 2 g of gold, about 30 g of silver, 2 – 3 kg of copper, 6 – 8 kg of zinc, purify industrial wash waters from arsenic and obtain environmentally friendly dumps. 1 salary files, 1 table.

Description

The invention relates to the hydrometallurgy of rare and non-ferrous metals and can be used to extract gold and silver from cinders obtained by burning iron pyrite (pyrite) and which are waste from sulfuric acid production.

At present, neither in domestic nor in foreign practice of gold recovery factories there is an effective technology that allows the extraction of precious metals from pyrite cinders of sulfuric acid production.

It is known to extract gold and silver from pyrite cinders with acidic thiosulfate-sulfate solutions followed by cementation of noble metals with zinc dust: t 70 o C, SO₃ 2- 10-30 g/dm 3, pH 1,5-2,0. The method is under study, due to the decomposition of the leaching agent, it is practically difficult to implement on a large scale (M.A. Belyavsky “Behavior of gold and silver in thiosulfate and sulfide environments in relation to the problem of hydrometallurgical processing of pyrite cinders.” Abstract for an academic degree Candidate of Technical Sciences, MISIS, M. 1988).

There is a known method for the selective extraction of zinc and copper from pyrite cinder, which includes two-stage leaching of cinders with an ammonia-water solution in the presence of a substance containing sulfide ions, namely sulfur pyrites. Automatic svid. N 1486534 USSR. MKI C 22 V 19/24, 15/10 from 15.06.89/XNUMX/XNUMX.

The closest to the proposed method and therefore chosen as a prototype is the method of extracting gold and silver, which consists of preliminary aeration of cinder pulp in an alkaline environment for the purpose of oxidation of sulfides, cyanidation, carried out in two stages to reduce the contact time of cyanidated metals and reducing agents and cementation of precious metals zinc dust. (Recuperation ae oro plata a parter ae cenizas ae pirita, Tratamiеnfos previos y cianuracion on doble etopa. Diaz. Ojeda E. Caranza F. Romero R. /Rev.Met./ CENIM 1988 24, N 6, p. 391-401- Uen.).

The disadvantages of this method include low recovery of gold (60%) and silver (40%), as well as the presence of high contents of copper and zinc in cyanide solutions, which depress the sorption of gold and silver.

It is proposed to subject the pyrite cinder to acid treatment, then separate the liquid phase, extract copper and zinc, grind the solid phase in the presence of lime, carry out aeration at elevated temperatures and pressure, and then cyanide it in the presence of a sorbent. Use wash water from sulfuric acid production as acidic solutions.

If necessary, solutions after separation of copper and zinc are further purified to the maximum permissible concentration of the impurities present. The condensed cinder pulp is limed, classified, the sands are further crushed to a content of class 0,01 mm. 95-98% classifier drain, condensed to a liquid to solid ratio of 1,5-2,5, is sent for oxidation in an autoclave, which is carried out at t 80 -150 o, RO₂ 1-3 atm for 1-3 hours; then the limed pulp, after cooling, is sent either for conventional cyanidation at a temperature of 30-40 o C, or for cyanidation at a temperature of 60-80 o C and pressure. The duration of cyanidation should not exceed two hours, followed by sorption leaching with the removal of resins saturated with gold and silver, the regenerated resins are returned to the sorption cycle, and the solutions are sent for refining. The condensed waste pulp is supplied to the destruction of cyanide or in an autoclave (t 100-160 o C, RO₂ 1-3 atm.) or other known methods. The neutralized pulp is filtered: the solutions are used for decantation washing of the cinder from acid, cake for the production of cement or iron pellets.

Thus, the processing of pyrite cinders according to the proposed method can significantly increase the extraction of noble metals by creating favorable conditions for their cyanidation and sorption, provided by the removal of non-ferrous metals at the head of the process and the intensive oxidation of depressants-reducers.

The essence of the invention is confirmed by an example.

EXAMPLE We extracted gold and silver from pyrite cinder, which is a waste product of sulfuric acid production and obtained by firing iron pyrites in KS furnaces.

Pyrite cinder had the following composition: silicon dioxide 18,0; iron oxide 47,0; ferrous iron 5,3; copper 0,45; zinc 1,1; arsenic 0,2; total sulfur 2,3; sulphide sulfur 0,85; gold 2,6 g/t; silver 42 g/t; and initial fineness 60% class 0,074 mm.

With direct cyanidation of the cinder, gold recovery was obtained: 42,3% silver 11,9%
According to the proposed method, pyrite cinder was washed with acidic solutions containing, g/dm 3: H₂SO₄ 54; As 0,46; at a T:F ratio of 1:0,8, for 3 hours at t = 60-70 o C. After phase separation, the content in the solution was, g/dm 3: total iron 16. copper 2,5; zinc 7,2; arsenic 1,2; sulfuric acid 12. The washed cinder was limed and crushed to a content of class 0,074 mm 95%. Next, the crushed cinder pulp was aerated at elevated temperatures and pressure, at T:L 1:2, then potassium cyanide was added and the cinder was first leached in an autoclave, then after cooling and loading of AM-2B anion exchange sorbent in an amount of 5% of the pulp volume for 8 hours at room temperature and atmospheric pressure. After sorption, the tail pulp was transferred to an autoclave for neutralization. Cyanide destruction occurred up to the maximum permissible concentration (0,1 mg/l). The recovery of gold and silver (see table) was 82,1 and 69,0%, respectively.

According to the prototype method, the pyrite cinder was also crushed to a fineness of 95% class up to 74 mm, then limed under conditions T:L 1:2, pH 11, t 20 o C, atmospheric pressure; At the same time, intensive aeration of the alkaline pulp was carried out by supplying air through dispersants for 8 hours, then the pulp followed the first cyanidation, after two hours from the moment of the cyanide task, phase separation occurred, the solution proceeded to the cementation of noble metals with zinc dust, the cake to the second stage of cyanidation. The total duration of both cyanidation treatments was 4 hours.

The recovery of gold and silver into the solution was 61,5 and 40,5%, respectively.

The use of the proposed method makes it possible to increase the extraction of precious metals by 20-30%, thus from each ton of cinder, which is a waste of sulfuric acid production, more than 2 g of gold, about 30 g of silver, 2-3 kg of copper, 6-8 kg of zinc can be extracted, purify industrial wash waters from arsenic and obtain environmentally friendly waste dumps, which can be used in the construction or metallurgical industries.

Claims (2)

1. METHOD FOR EXTRACTING NOBLE METALS FROM PYRITIC CANDLES, including aeration in an alkaline medium and cyanidation, characterized in that before aeration the source material is subjected to acid treatment with separation of the liquid phase from the solid, followed by separation of copper and zinc from the liquid phase, and the solid phase is subjected to further grinding in the presence of lime and aeration is carried out at a temperature of 80-150 o C and a pressure of 1-3 atm, followed by cyanidation in the presence of a sorbent.

2. The method according to claim 1, characterized in that wash waters from sulfuric acid production are used as acidic solutions.

SU5040554 1992-04-29 1992-04-29 Method for extracting precious metals from pyrite cinders RU2034062C1 (ru)

Priority Applications (1)

Application Number	Priority Date	Filing Date	Title
SU5040554 RU2034062C1 (ru)	1992-04-29	1992-04-29	Method for extracting precious metals from pyrite cinders

Applications Claiming Priority (1)

Application Number	Priority Date	Filing Date	Title
SU5040554 RU2034062C1 (ru)	1992-04-29	1992-04-29	Method for extracting precious metals from pyrite cinders