RU2475639C2 - Method of bath-well leaching of metals - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method of bath-well leaching of metals from ores includes treatment of mineral mass by solution of leaching in baths and metal winning from product solution. Baths are formed along leached mass, in the baths bottom a system of injection and extraction wells is built located above the level of bath with depth not less than the lower point of leached layer of mineral mass, and baths are filled with agglomerated mineral mass or pulp prepared in advance from extracted material, mineral mass in baths is treated by solution of leaching, and metal is extracted from product solution. Reusable solution obtained after metal extraction is strengthened or replaced with solution of another composition and is supplied to the system of injection wells for leaching of lower layers of material, then working solution is pumped off with leached metal through the system of extraction wells and metal is extracted from it; for leaching of lower layers of material solutions of environmentally safe chemicals, such as chlorides or thiosulfates, are used.

EFFECT: invention allows improving metal extraction efficiency.

Description

The technical solution relates to the mining industry, namely to the enrichment of minerals by physicochemical methods, and can be used in the processing of refractory ore mineral raw materials and industrial wastes.

A known method of downhole leaching of metals from oxidized ores, including the sequential injection of reagent solutions into the formation through a system of injection wells and pumping productive solutions through a system of pumping wells, followed by processing of the productive solution and decontamination of the landfill by pumping a sodium thiosulfate solution to obtain a pumping solution having a pH of formation water ore-bearing horizon (see RF patent No. 2074958, IPC E21B 43/28, publ. 03/10/1997).

The disadvantages of this method include: low intensity and degree of leaching, due to poor study of solutions of the upper part of the ore deposits or embankments from mineral raw materials.

A known method of cuvette-heap leaching of metals from refractory ores (see RF patent No. 2350665, IPC C22B 3/18, publ. 03/27/2009), comprising treating the mineral mass with a solution of the leaching reagent in the cuvettes, separation after leaching of the bulk of the metals of the sand fraction, the formation of bulk or alluvial formations from it, heap leaching and metal precipitation from a productive solution.

The disadvantages of this method include the relatively high operating costs due to the movement of all volumes of leached mineral mass from the place of occurrence or storage.

The technical result of the proposed method is to increase the efficiency of metal extraction due to the cuvette method of leaching from the upper layers of the mineral mass and downhole leaching from the main part of the object.

The problem is achieved in that the method of cuvette-hole leaching of metals from ores, special dumps and stale tailings, including treating the mineral mass with a solution of the leaching reagent in the cuvettes and separating the metal from the productive solution, is characterized in that the cuvettes are formed according to the leached mass in the bottom the cuvette is constructed a system of injection and pumping wells located above the level of the bottom of the cuvette and with a depth of not less than the lower mark of the leachable layer of mineral mass, fill the cuvette with an agglomerated mineral mass or pulp prepared from previously extracted material, the mineral mass in the cuvettes is treated with a leaching reagent solution and the metal is extracted from the productive solution, then the working solution obtained after the metal is isolated is further strengthened or replaced with a solution of a different composition and fed to the injection well system for leaching the lower layers of the material, then the working solution with leached metal is pumped out through a system of pumping wells and s metal therefrom, wherein the lower layers of the leach solution using a material environmentally safe reagents, such chlorides or thiosulfates.

Compared with the existing method, the proposed method, by combining the cuvette method of leaching from the upper layers of the mineral mass and downhole leaching from the main part of the object, allows to increase the completeness of metal extraction by separately treating the weakly filtering fine-grained mineral mass of the upper part of the material with a leach solution, ensuring its full contact with the solution during the agglomeration, during the formation and mixing of the pulp obtained from it and filtering well tnositelno krupnofraktsionnoy parts mineral mass reactant solution supplied through the borehole and reduce metal recovery costs by reducing the length of pumped and stored pressure wells.

The method is implemented as follows. The cuvettes preliminarily pass through the mineral mass with temporary storage of the extracted part with its possible agglomeration. Wells are drilled from the bottom of the cuvette to the depth of the leached layer and cased with the outlet of the upper part of the pipe above the level of the mouth, they are equipped with filters and aerial lifts (airlifts). The upper parts of the casing are connected by horizontally arranged pipes or hoses. In this case, injection and pumping wells are separately connected. The bottoms and sides of the trenches are sealed and covered with dense waterproof films. The contact points of the film with the pipes are fixed with seals. Next, the mineral mass extracted from the trenches is fed into the mixer, where the pulp is prepared and then, together with the leaching reagent, is fed into the cuvettes or, if the mineral mass has undergone agglomeration, it is poured into the cuvettes and poured with a leaching solution. After leaching of metals from the mineral mass placed in the cells, the solution is sent to sorption or extraction columns, where the leached metals are extracted. Obtained, after isolation from the productive metal solution, the circulating solution is either strengthened or replaced with a solution with another complexing agent and fed into injection wells, which leaches the metals from the main part of the ore body or man-made mineral formation. Next, the working solutions with leached metal are lifted through pumping wells by aerial lifts (airlifts) and pumped to sumps or mechanical filters and then to sorption (or extraction) columns where metals are extracted.

Example.

Darasun tailing dump with an average gold content of 0.87 g / t in mineral mass. The thickness of the layer (the depth to the soil) of the dried mineral mass is from 5 to 8 meters. The underlying soil layer is waterproof. The upper part of the deposits to a depth of 1.5-2 m is represented by fine-grained (30-70 μm) material. The filtration coefficient for this material does not exceed 0.1 m / day; therefore, leaching of gold, mainly dispersed gold, from it can be effectively carried out only after agglomeration with the addition of a solution of sodium cyanide with a concentration of 2 g / l, cement and calcium oxide. Below these marks, the size of mineral particles is 50 microns - 500 microns. The filtration coefficient for this material is about 0.2-0.5 m / day, which is close to the optimal values for PV. Therefore, it is more expedient to leach gold from the lower layer by the borehole method using chloride-peroxide complexes. To carry out the method, cuvettes with a depth of 1.5-2 m, a length of 30 m, a width of 5 m along a gold-containing mineral mass pass with temporary storage of the extracted part with its possible agglomeration by the above mixture. Wells with a diameter of 100 mm are drilled from the bottoms of the cuvette to a depth of the leached layer of up to 8 m, they are lined with plastic pipes with their top part being brought out 2 meters above the wellhead level, equipped with slotted filters, gravel backfill and airlifts (airlifts). The upper part of the slots in future injection wells is left protruding relative to the bottom of the trench for subsequent bubbling of the solution during cuvette leaching. The upper parts of the casing are connected by horizontally placed plastic hoses. In this case, injection and pumping wells are separately connected. The bottoms and sides of the trenches are sealed and covered with dense waterproof films. The contact points of the film with the pipes are fixed with special foaming seals. The mineral mass extracted from the trenches is mixed with cement, calcium oxide and poured into a rotating drum, where by feeding a 0.2% cyanide solution prepared on the basis of a primary solution of soda or alkali that has undergone photoelectrochemical treatment, a mixture is prepared from which pellets are obtained by agglomeration . Then the pellets are served in ditches. After that, the agglomerated mineral mass is irrigated with a leaching reagent - 0.02% sodium cyanide solution until the cell is filled with it. Through pipes, with slots protruding at the exit from the bottom of the trench, periodically (after 0.5 hours), lasting 1 hour, compressed air is pumped for sparging, installing plugs in the upper part of the pipes to exclude its losses and loss of solution. Bubbling provides an increase in the intensity and completeness of the cuvette leaching process. After leaching of metals from the mineral mass placed in the cuvettes, the solution is sent to sorption columns filled with A-100 ion-exchange resin, where leached gold is extracted. The circulating solution obtained after isolation from the productive metal solution is fed to separate sorption columns with an AM-2B type anion exchange resin in the OH form, where the main part of the cyanides is recovered, put into sludge, where the remaining part of the cyanides is neutralized with sodium hypochlorite, pumped out, and dosed into hydrochloric acid is passed through a photochemical reactor, where compounds with active chlorine are formed, and pumped into wells. The active solution from the sump, entering the injection wells through cracks and gravel filling, passes into the mineral mass and leaches gold from the main part of the corresponding section of the tailing dump. Then, working solutions with leached metal are lifted through pumping wells by aerial lifts (airlifts) and pumped to sumps or mechanical filters and then to sorption columns loaded with AG-3 coal, where gold is extracted.

Claims (1)

The method of cuvette-well leaching of metals from ores, special dumps and stale tailings, comprising treating the mineral mass with a solution of leaching reagent in cuvettes and separating metal from the productive solution, characterized in that the cuvettes are formed according to the leached mass, and a pumping and pumping system is constructed in the bottom of the cuvette wells located above the level of the bottom of the cuvette and a depth of not less than the lower elevation of the leached layer of mineral mass, the cuvettes are filled with agglomerated mineral m with assa or pulp prepared from previously extracted material, the mineral mass is treated in cuvettes with a solution of a leaching reagent and the metal is extracted from the productive solution, then the working solution obtained after the metal is isolated is further strengthened or replaced with a solution of a different composition and fed to the injection well system for leaching the lower layers material, then the working solution with leached metal is pumped out through the system of pumping wells and metal is extracted from it, while for leaching Ivanov lower layers of material is environmentally safe reagents solutions, e.g. chlorides or thiosulfates.