RU2490345C1 - Method for extraction of disperse gold from refractory ores and technogenic mineral raw material - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method involves agglomeration of initial raw material by adding to it of binding material, formation of a pile, leaching of gold with a reagent solution leaching the gold, collection of working solutions and extraction of gold from it. At agglomeration of raw material, to mineral mass there added is carbonate-alkaline solution containing dissolved carbon dioxide and active oxygen obtained as a result of series electrochemical and photochemical treatment of sodium solution. After that, gold is leached from agglomerated material first in a penetration-diffusion mode by supply of active concentrated solution of a leaching reagent till formation of wetting films of agglomerated material, and then, after accumulation in them of dissolved gold, in infiltration, filtration or agitation modes with oxygenated water or weak solution of leaching reagent, with repetition of a cycle till economically feasible level of extraction.

EFFECT: improved leaching efficiency.

4 cl, 1 ex

Description

The invention relates to hydrometallurgy of non-ferrous and noble metals, namely to the extraction of gold from refractory ores and man-made mineral raw materials and is intended for the extraction of industrially valuable metals.

A known method of leaching gold from ores, including crushing them, forming stacks from crushed ores, irrigating the stack with a solution of leaching reagents and collecting productive solutions (see Heap and underground metal leaching M., Nedra. 1982).

The disadvantage of this method is its low efficiency due to the low extraction of fine and fine gold, which makes up the bulk of the reserves of refractory ores and technogenic formations, due to the low permeability of ores for solutions and their insufficient access to intramineral inclusions of gold.

Closest to the claimed is a method of extracting dispersed gold from refractory ores and industrial mineral raw materials, including sintering the gold-containing mineral mass of the feedstock by adding a binder to it, forming a stack, leaching of gold by feeding a solution of gold leaching reagent to the stack, collecting working solutions, followed by the allocation of gold from them (see RF patent No. 2361937, C22B 11/00, publ. 20.07.2009).

The effectiveness of this method is also not large enough due to the impossibility of extracting most of the dispersed gold contained in the particles of quartz and chalcedony, as well as sulfide-sulfosalt (sulfosol) minerals.

The technical result of the invention is to increase the efficiency of extraction of gold from ores and man-made mineral formations by increasing the extraction of dispersed gold contained in particles of quartz and chalcedony, as well as sulfide-sulfosalt (sulfosol) minerals.

The specified technical result is achieved by the fact that the method of extracting dispersed gold from refractory ores and technogenic mineral raw materials, including sintering the gold-bearing mineral mass of the feedstock by adding binder to it, forming a stack, leaching gold by feeding a solution of gold leaching reagent to the stack, collecting working solutions followed by the separation of gold from them, characterized in that during agglomeration an additional carbonate-alkaline solution is added to the mineral mass, with containing dissolved carbon dioxide and active oxygen, obtained as a result of sequential electrochemical and photochemical treatment of a soda solution with which the components of mineral matrices of materials containing dispersed gold are oxidized, leached or transferred to a mobile state, after which gold is leached from the agglomerated material, initially into penetration diffusion mode by feeding an active concentrated solution of leaching reagents to form wet agglomerates material of the films, and then, after the accumulation of dissolved gold in them, in the infiltration, filtration, or agitation modes with oxygenated water or a weak solution of leaching reagents, with a repeat of the cycle to an economically justified recovery level.

The method also differs in that hydrogen peroxide is introduced into the active soda solution after electrochemical treatment and photochemically treated with a UV lamp.

The method also differs in that the separation of gold is carried out from the working solution in sorption columns by sorption carried out stepwise after each leaching cycle.

The method is characterized in that before loading into the sorption columns, sorbents are prepared in a carbonate-alkaline solution obtained by photoelectrochemical treatment with additional UV irradiation in a thin layer.

Distinctive features of the proposed method is that during agglomeration (pelletizing) an additional carbonate-alkaline solution containing dissolved carbon dioxide and active oxygen is added to the mineral mass, obtained as a result of sequential electrochemical and photochemical treatment of the soda solution, which is oxidized, leached or transferred to a mobile the state of the components of mineral matrices containing dispersed gold, after which gold is leached from the agglomerated material ala, initially in the penetration-diffusion mode by introducing an active concentrated solution of leaching reagents to form films wetting the agglomerated material, and then, after the accumulation of dissolved gold in them, in infiltration, filtration or agitation modes with oxygenated water or a weak solution of leaching reagent, with the cycle repeated until economically viable recovery rate.

The method is as follows.

An active alkaline soda solution is prepared in an electrochemical reactor by sparging with air and subsequent electrolysis with the formation of dissolved diatomic oxygen and carbon dioxide released at the anode, and then the formation of active oxygen (ozone, hydrogen peroxide, hydroxyl radical by irradiation of the electrolysis solution with UV light in the range electromagnetic wavelengths of 180-300 nanometers by circulating the solution through submersible UV lamps or by irradiation with mounted (external) UV lamps with continued electric lysis, mainly in the anode zone. Sodium hydroxide (alkali) is formed in the cathode region of the reactor. The resulting carbonate-alkaline solution containing reactive oxygen species, together with a binder, is used to agglomerate the technogenic mineral mass containing useful components. As a result, active oxidizing and the complexing components of the solution begin to diffuse into the upper layers of the mineral matrices containing dispersed gold, with the intense leaching of iron and edi hydrogencarbonates, active oxygen oxidation of sulfur to form sulfates, which provide a total mineral matrix preparation to a subsequent leaching of "free" and included in a mineral matrix gold. Moreover, since the solution has an alkaline base, arsenic in the composition of arsenopyrite and other arsenates remains in the solid phase. The complex effect on the matrices of gold-containing mineral particles of quartz and chalcedony, dissolved carbonates and bicarbonates, in combination with carbon dioxide and sodium hydroxide obtained during the electrochemical treatment of the initial soda solution, forms quasi-liquid surface regions of hydrated polysilicon compounds in these minerals, which enable subsequent penetration into deep layers of their complexing matrices and their interaction with dispersed gold. Moreover, the carbon dioxide-hydroxide complex does not have a destructive effect on complexing compounds, including cyanides. At the same time, pelletized material acquires good permeability for an active concentrated solution containing complexing agents. In the event that the gold-containing mineral mass contains significant amounts of sulfosalts and / or carbonaceous matter, then when preparing the active solution, after electrolysis of the initial soda solution, hydrogen peroxide is additionally introduced, which, upon subsequent UV irradiation, produces a stronger oxidizing agent, hydroxyl- radical.

After pelletizing in a rotating drum, the mineral mass is stacked in piles (on a prepared site or in a cuvette) and kept in them for 1-2 days to ensure the preparation of gold-containing mineral matrices for subsequent leaching.

Through emitters placed in pipes (hoses) laid on the surface of the stacks, or through immersion pipes and nozzles, a two-stage irrigation of the stack is carried out: initially with a concentrated solution of the main leaching reagents, and then, after holding a pause of 2-4 days, with oxygenated water or a weak solution of the main reagent . Processing the prepared agglomerated material with a small amount of a concentrated solution with a complexing agent for gold, followed by aging for 2-4 days, ensures its leaching in the penetration-diffusion mode. Subsequent irrigation of the agglomerated material with water or a weak reagent solution ensures the extraction of leached gold from the film liquid into the bulk of the resulting solution, which moves in a stack in the filtration or infiltration mode. With a large amount of clay or sludge particles in the leached material, the slightly agglomerated material can be completely flooded with a solution with the formation of pulp, which can be mixed with airlifts and pumped out of the cell after leaching with pumps. In this case, after agglomeration of such a material with an active soda-alkaline solution, it is mixed with a stage 1 sorbent before laying in a trench (cuvette), thus, upon subsequent irrigation of the material with a concentrated solution of the main leaching reagent, the sorption leaching process immediately begins. After a weakly concentrated reagent solution or oxygenated water is fed into the cuvette until a pulp is formed, the sorbent of the first stage is separated from it by sieves and the sorbent of the second stage is fed into the process.

In a heap embodiment of the proposed method, for the full development of the material of the stacks, their formation is preferable to carry out with the parallel placement in them of a system of perforated pipes and pipes orthogonally oriented relative to each other. Thus, the use of "volumetric" irrigation through a system of pipes and nozzles is ensured, in which the channeling effect is virtually eliminated - the movement of solutions inside the stack in separate streams with the leaving of "dry" zones. After releasing the first concentrated working solution from the stack, collecting it in a drainage ditch and pumping it onto the surface to sorb dissolved gold with a stage 1 sorbent, a small amount (not more than 1:10 with respect to the volume of leached material) is re-fed into the stack again (after sorption of gold from it) or a freshly prepared active concentrated leach solution. Further, after the next keeping it in the stack for 1-2 days, the cycle repeats - an intensive supply of low concentrated reverse dehydrated dehydrated oxygenated solution (obtained after sorption or deposition of gold from it) is carried out into the stack. A low concentrated reagent solution formed in a stack ensures the collection of leached gold from film water and its additional leaching from mineral matrices.

Gold from sorbing solutions of the first and second stages of heap leaching is sorbed or precipitated in separate chains of columns, since they have a significantly different salt composition and content of gold and associated valuable metals. The cycles of the second leaching stage are repeated until the metal concentration in the working solutions decreases below a critical value. To increase the sorption activity, respectively, of the sorption capacity of coal or resin, they are treated with the same active carbonate-alkaline solution, which is used for agglomeration with additional irradiation in a thin layer with UV lamps.

Such treatment will allow the formation of additional carboxyl groups on the surface of coal particles or increase the activity of the film phase of the ion exchanger.

An example of a specific use of the method.

The method was tested on the stagnant tailings of the ore of the Darasunskoye deposit, in which there is dispersed gold not recovered in concentrate contained in mineral particles of chalcopyrite, arsenopyrite, quartz, chalcedony. Moreover, such gold is not extracted from the tailings by heap leaching using a simple “oxygenated” cyanide solution (see protocol, schemes 1, 2), but only with the proposed active solutions (scheme 3).

An active carbonate-alkaline solution was prepared from a 1% soda solution in an electrochemical reactor by sparging with air to saturate with oxygen for 1 hour, electrolysis for 1 hour, then injected to a concentration of 1% hydrogen peroxide and irradiated with UV light in the range 180- 300 nanometers with DRT-230 lamps for 30 minutes The resulting solution, together with cement and lime, 5 kg / t was used for separate agglomeration of medium-grained and sludge-clay clay tailings containing useful components. For the former, cement consumption was 3 kg / t; for the latter, 2 kg / t. After pelletizing in a rotating drum, the mineral mass of these types of tailings in the form of pellets was separately stacked. The agglomerated mineral mass of medium-grained stale tailings was laid on a surface in a stack of 2.5 m high, which was equipped with a system of perforated plastic pipes and perforated pipes with a diameter of 1.5 cm attached to them with end caps, kept for one day and fed through them a concentrated solution of sodium cyanide prepared on the basis of the same active soda solution, but without the addition of hydrogen peroxide obtained by electrochemical and photochemical processing, from the calculation and 500 g of cyanide / t solid as the main leaching reagent and conditioning alkali, added until the solution reaches pH = 10.5. Then the solution was kept in a stack for 2 days, leaching gold in the penetration-diffusion mode from sulfide, sulfo-arsenide, sulfosalt (sulfosol) minerals, quartz and chalcedony. After that, a stack of oxygenated water was irrigated through pipes and nozzles to T: W = 10: 3, which ensured the transfer of leached gold to the formed diluted mobile working solution. Working solutions of the first leaching stage with a gold concentration of more than 20 mg / L were collected in a drainage ditch and fed to sorption columns of the 1st stage of sorption, in which ion-exchange resins prepared in an active alkali-reinforced solution were placed, sorbing complex anions of iron, copper, silver and gold. The gold content of the resin was 7 mg / g. After the solution was leached out of the first leaching stage, a concentrated (2%) sodium cyanide solution was again freshly prepared on the basis of an active soda solution and was added to the stack at the rate of T: W = 10: 1, which was kept in the stack for two days, after which it was fed into the stack anhydrous solutions of the first stage. At the same time, such anhydrous solutions with impurities extracted from them were strengthened with cyanide and saturated with atmospheric oxygen before being fed to re-irrigation. Working solutions of the second stage, after releasing them from the stack, were sent to coal sorption columns. The concentration of gold on coal was 5 mg / g. Next, the resin and coal were sent for desorption. Anhydrous solutions were added with cyanide to a concentration of 300 mg / L, oxygenated with air and pumped into a stack to control gold recovery. The cycles of the second leaching stage were continued until a critical concentration of gold in solution of 0.5 mg / L was reached.

Weakly agglomerated material of sludge-clay particles was mixed in a volume ratio of 20: 1 with A-100 ion-exchange resin prepared in an active alkali-reinforced solution, irradiated in a thin (10 cm) layer with a UV lamp, and placed in 20 * 5 cuvettes * 1.5 m with waterproof sides and bottom. After 2 days of standing, a 2% solution of sodium cyanide from the ratio T: W = 7.5: 1 was fed into the cuvette through perforated tubes and the cuvettes were closed with a film on top. The material with the cyanide solution stood for 3 days, after which oxygenated water was supplied to the cuvette to the ratio W: T = 1: 1, with the formation of pulp, which was mixed with airlifts for an hour. After this, the pulp, with stirring by airlift, was passed through a mesh drum with an inclined axis, in which the 1st stage resin was separated from the pulp. Then, a strengthening active solution of sodium cyanide, a fresh resin prepared in the active solution at the rate of 2% of its volume, was fed into the pulp. Mixing the pulp with resin airlifts continued for one day with 2-hour breaks after an hour of active bubbling.

After the completion of the sorption leaching process, the saturated stage 2 resin was separated on a mesh drum when the pulp was pumped out of the cell by pumps. The content on the resin of the first stage of gold is 7.5 mg / g, the second - 5.3 mg / g. The total gold recovery from the Darasun tails was 82%.

Claims (4)

1. A method of extracting dispersed gold from refractory ores and man-made mineral raw materials, comprising agglomerating a gold-containing mineral mass of the feedstock by adding a binder to it, forming a stack, leaching gold by feeding a solution of gold leaching reagent to the stack, collecting working solutions, followed by separation from it gold, characterized in that during agglomeration, a carbonate-alkaline solution containing dissolved carbon dioxide and active ki is additionally added to the mineral mass hydrogen sulfide obtained by sequential electrochemical and photochemical treatment of a soda solution with which the components of mineral matrices of materials containing dispersed gold are oxidized, leached or transferred to a mobile state, after which gold is leached from the agglomerated material, initially in the penetration-diffusion mode, by supplying an active concentrated leaching solution reagent before the formation of films wetting the agglomerated material, and then, after accumulation they contain dissolved gold, in infiltration, filtration or agitation modes with oxygenated water or a weak solution of a leaching reagent, with the cycle repeated to an economically justified recovery level. 2. The method according to claim 1, characterized in that hydrogen peroxide is introduced into the active soda solution after electrochemical treatment and subjected to photochemical treatment with a UV lamp. 3. The method according to claim 1, characterized in that the separation of gold is produced from the working solution in the sorption columns by sorption, carried out in stages after each leaching cycle. 4. The method according to claim 3, characterized in that before loading into the sorption columns, the sorbents are prepared in a carbonate-alkaline solution obtained by photoelectrochemical treatment, with additional irradiation with UV rays in a thin layer.