The method of extracting gold from ores, concentrates and sludge

 

(57) Abstract:

The invention relates to hydrometallurgy and can be used to extract gold from ores, concentrates and sludges. The method includes the cyanidation of raw materials by fractional solution supply cyanide salt in the crushed pulp, gold sorption from synthetic sorbent containing a strongly - and weakly basic functional groups in the cascade devices with mesh drainage for a fixed volume of sorbent in the apparatus and the flow countercurrent pulp and sorbent with a certain time last thread with subsequent desorption of gold from the saturated sorbent. The concentration of cyanide salts in the pulp support up to 1.5 g/l, use synthetic sorbent, containing as functional groups of the Quaternary, tertiary, secondary and primary amino groups in the ratio, wt.%: Quaternary to 2.5, tertiary 10-25, secondary 45-60, primary 20-35, gold sorption from the pulp is carried out at pH 8.0 and 10.8, desorption of gold from the saturated sorbent is carried out at a temperature of 50-70C alkaline-cyanide solution, in particular a solution containing 2-10 g/l NaOH and 5-20 g/l NaCN, and decorate after extraction of the gold return is, the grain size of the grains which is determined from the relationcm> 2,5TVwherecm- the minimum size of a grain of sorbent,TV- the maximum size of the grain of the solid particles in the ore pulp (mm). For the most complete extraction of gold from ores with different content of sorption is carried out at a loading of sorbent in the amount of 0.5-10% by volume of the apparatus and the time flow of the sorbent 0,03-2,00% of the flow of pulp. The technical result is to reduce the time of regeneration of the sorbent in 5-10 times, reducing the consumption of chemical reagents, except high temperature treatment of the sorbent during regeneration, the rejection of the use of acid-resistant equipment, improving the safety of maintenance personnel due to the lack of selection poisonous hydrocyanic acid. 6 C.p. f-crystals, 5 PL.

The invention relates to hydrometallurgy and can be used to extract gold from ores, concentrates and sludges.

The method for extracting gold from ore slurries of sorbsil [1], including a preliminary cyanidation, countercurrent sorption leaching at fractional filing cyanide salts on stage process with gold sorption porous sorbent AM-2B containing a strongly - the enta AM-2B is a complex and lengthy process, when consuming expensive thiourea and produces a large quantity of vapour of hydrocyanic acid, which require special measures for its recovery. The total time of regeneration of the sorbent in hydrometallurgical plants up to 200 - 300 hours, which necessitates more simultaneous loading of the sorbent and requires a high transportation costs by stages of processing.

There is also known a method of extracting gold from the pulp on activated carbon [2], involving pre-treatment of the pulp with solutions of cyanide salts, sorption of gold from cyanide sludge activated carbon and regeneration of the coal allocation of gold in the commodity chemicals, including the most simple variants of alkaline-cyanide processing of coal with subsequent one - or multi-stage heat treatment at a temperature of from 450o650oC. the disadvantages of this method include low capacity of the sorbent with respect to gold, the lower the affinity of cyanide complex to coal than to synthetic sorbents, which leads to low recovery of gold from ore slurries, as well as large losses of activated carbon due to mechanical abrasion. In addition, aktivirovani the intensive operations to high temperature treatment in the regeneration of the sorbent.

The closest technical solution is the method of extracting gold from ores, concentrates and sludge [3], which includes sorption leaching in the cascade AIDS raspolojennoe in water raw alkaline cyanide salt used for sorption of gold porous synthetic adsorbent containing a strongly - and weakly basic functional group, when loading of the sorbent 0.1 to 1.5% of the volume of the apparatus and the time flow of 0.1-1.0% of flow of the pulp. Subsequent regeneration of the sorbent is carried out successively with a solution containing 40 - 50 g/l of sulfuric acid and 2 - 8 g/l of hydrogen peroxide and a solution containing 60 to 90 g/l of thiourea. The disadvantages of the method include the following: first, the above loading of the sorbent valid in the implementation of the described method is only for the poor gold ores (up to 1.5 g/t), as it depends on the content of gold in the pulp entering the sorption and capacity of the saturated sorbent gold. Secondly, after treatment of the sorbent thiourea in its pores accumulate elemental sulfur, which prevents reuse of the sorbent for the extraction of gold. For desorption of sulfur necessary to apply additional alkaline treatment, which significantly activly method of extracting gold from ore slurries followed technologically simple regeneration of the sorbent.

To solve this problem is proposed a method of extracting gold from ores, concentrates and sludge, which includes the cyanidation of raw materials by fractional solution supply cyanide salt in the crushed pulp, gold sorption from synthetic sorbent containing a strongly - and weakly basic functional groups in the cascade devices with mesh drainage for a fixed volume of sorbent in the apparatus and the flow countercurrent pulp and sorbent with a certain time last thread with subsequent desorption of gold from the saturated sorbent. The proposed method differs from the previously known fact that the concentration of cyanide salts in the pulp support up to 1.5 g/l, use synthetic sorbent, containing as functional groups of the Quaternary, tertiary, secondary and primary amino groups in the following ratio (wt.%): Quaternary - to 2.5, tertiary - 10-25, secondary - 45-60, primary 20-35, gold sorption from the pulp is carried out at pH 8.0 and 10.8, desorption of gold from the saturated sorbent is carried out at a temperature of 50 - 70oC alkaline cyanide solutions, in particular with a solution containing 2 - 10 g/l NaOH and 5-20 g/l NaCN, and desorbent after extraction of gold who is the sorbent, the grain size of the grains, which is determined from the relationcm> 2,5TVwherecm- the minimum size of a grain of sorbent andTV- the maximum size of the grain of the solid particles in the ore pulp (mm). For the most complete extraction of gold from ores with different content of sorption is carried out at a loading of sorbent in the amount of 0.5-10% by volume of the apparatus and the time flow of the sorbent 0,03-2,00% of the flow of pulp.

The technical result of the invention is that the use of the proposed method will reduce the time of regeneration of the sorbent in 5 - 15 times compared to known technologies to reduce the consumption of chemicals and avoid high temperature or heat treatment of the sorbent during regeneration, to reduce the number of pumps and valves and to refuse the use of acid-resistant equipment when implementing a method for the hydrometallurgical plants. In addition, the lack of allocation of poisonous hydrocyanic acid will lead to significant improvements in the safety of operating personnel.

The invention was carried out as follows.

Example. Conducted preliminary cyanidation of ore one of the field is Itanium synthetic sorbents used in industry sorbent AM-2B (content of Quaternary amine groups - 17,0%, tertiary - 83.0 per cent) and the proposed sorbent, containing as functional groups of 1.1% Quaternary, 18.5% of the tertiary, 52% of secondary and 28.4% of primary amino groups. Sorption was carried out under the following conditions: the amount of pulp in one device - 20 m3the feed rate of the pulp on the sorption - 21 m3per hour, the density of the pulp - 1,36 g/3. In table. 1 presents the composition of the original pulp.

Experience 1. The loaded sorbent to 3.7% (8.9 m3), the time flow of the sorbent at 0.020 m3/hour, which corresponds to the value 0,095% of the flow of pulp. The results of sorption are shown in table. 2.

Experience 2. Download sorbent is 1.5% (3.6 m3), the time flow of the sorbent at 0.020 m3/hour, which corresponds to the value 0,095% of the flow of pulp. The results of sorption are shown in table. 3.

Experience 3. Download sorbent is 1.5% (3.5 m3), the time flow of sorbent - 0,040 m3per hour, which corresponds to 0.19% of the flow of pulp. The results are shown in table. 4.

As can be seen from the above results, the performance of sorption process (extraction of gold from solution, the capacity of the sorbent and its selectivity for gold) is largely determined by such criteria as the percentage loading of the sorbent and its time stream. So, if you compare show the second experiment the gold extraction sorbent decreased from 99,66% to 76,14% (proposed sorbent) and to 95,68% (S-2B). When this capacity has decreased and the selectivity of the sorbents in gold. Comparison of the 2nd and 3rd experiments shows that the equivalent loads sorbents increase their hourly flows has led, on the one hand, to an increase in the extraction of gold, and on the other hand, to the reduction of the capacity and selectivity of the sorbents in gold. In all experiments, the selectivity of the proposed sorbent gold is more than one and a half times the selectivity for gold sorbent AM-2B.

Desorption of gold (regeneration of sorbents).

Desorption of gold from saturated sorbents (experiment 1, table. 2) with simultaneous regeneration of the latter was carried out with a solution containing 5 g/l NaOH + 20 g/l NaCN at a temperature of 60oC. regeneration Time is 24 hours (including 18 hours of treatment desorbers solution, 6 hours - water washing). The results of regeneration are given in table 5.

From table 5 it follows that the application of a Stripping solution containing 5 g/l NaOH + 20 g/l NaCN, the conditions made it possible to clear the proposed sorbent 96.2% when the degree of desorption of gold of 99.5%. The use of such a Stripping solution for the regeneration of S-2B is impossible due to its low performance.

Thus, the inventive method is C ladidadidadi environments with high performance;

to increase the selectivity of the extraction of gold in the sorbent;

- reduce in comparison with the known solutions, the time of regeneration of the sorbent in 5 - 15 times;

to renounce the use of expensive and hazardous reagents (thiourea and acid) for regeneration of the sorbent;

- to create favorable conditions for the subsequent processing of gold reagents with obtaining gold of high purity;

to apply practically non-reagent regeneration, because salt cyanide and alkali after the extraction of gold from alkaline cyanide regenerates return to the stage cyanidation of ore.

Sources of information

1. I. M. Malinetskii, L. C. Chugaev. Metallurgy of noble metals. M.: metallurgy, 1972, S. 202-219.

2. "New methods of extraction of precious metals in North America". Mining Engineering, Sept., 1993 S. 1144-1151.

3. Patent USSR N 1790619, MK C 22 B 11/08. The method of extracting gold and silver from ores, concentrates and sludges. Published 23.01.93. Bull. N 3.

1. The method of extracting gold from ores, concentrates and sludges, including cyanidation of raw materials by fractional solution supply cyanide salt in the crushed pulp, gold sorption from synthetic absorbents is cerovina the load capacity of the sorbent in the apparatus and the flow countercurrent pulp and sorbent with a certain time flow of sorbent and subsequent desorption of gold from the saturated sorbent with getting decorativ, characterized in that the concentration of cyanide salts in the pulp support up to 1.5 g/l, use synthetic sorbent, containing as functional groups of the Quaternary, tertiary, secondary and primary amino groups, the sorption of gold from the pulp is carried out at pH 8.0 and 10.8, and desorption of gold from the saturated sorbent carry out alkaline-cyanide solution at a temperature of 50 - 70oC.

2. The method according to p. 1, characterized in that use synthetic sorbent containing functional groups in the following ratio, wt.%:

Quaternary amino - 2.5

The tertiary amino - 10 - 25

Secondary amino group - 45 - 60

The primary amino group of 20 - 35

3. The method according to p. 2, characterized in that the sorption of gold from the slurry using a sorbent particle size of the grains which is determined from the relation

cm> 2,5TV,

wherecm- the minimum size of a grain of sorbent, mm;

TV- the maximum size of the grain of the solid particles in the ore pulp, mm

4. The method according to p. 1, characterized in that the sorption of gold from the pulp is carried out at a loading of sorbent in the amount of 0.5 - 10% by volume of the device.

5. The method according to p. 1, characterized in that Sorbs trichosis fact, that desorption of gold from the saturated sorbent implement a solution containing 2 - 10 g/l NaOH and 5 - 20 g/l NaCN.

7. The method according to p. 1, characterized in that decorate after extraction of gold returns to the initial process of cyanidation.

 

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SUBSTANCE: proposed method includes additional dissolving of oxygen in cyanide solution in the amount of 33-38 mg/l for obtaining required degree of extraction of gold in product solutions equal to 80% during 10-15 days of leaching-out of crushed ore. Expenses for oxygen do not exceed 1.1.5 rubles/t of ore.

EFFECT: increased productivity; increased extraction of gold into product solutions.

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