RU2747275C1 - Method for underground leaching of metals from sulfide-containing mineral raw materials - Google Patents

Abstract

FIELD: mining.SUBSTANCE: invention relates to the field of mining and, in particular, to the integrated development and use of mineral deposits. The method consists in the fact that in the reactor chamber, which is formed by the extraction of ore and the walls of which are formed by a solidified backfill, the bottom is erected from the backfill mixture, the raw material is loaded into the reactor chamber, drilled in the erected bottom of the well to remove the productive solution, the raw material is irrigated from above with a solution for leaching and withdrawing the productive solution through the wells in the bottom. After loading the raw material, it is pre-drilled in the erected bottom of the well to supply the oxidizing gas, after which the raw material is pre-oxidized with an oxidizing gas in a high-temperature mode in the temperature range from 200 to 900°C, while the oxidizing gas is fed through the wells to supply the oxidizing gas and the waste sulfur-containing gases from the upper part of the chamber, and drilling in the erected bottom of the wells to remove the productive solution is carried out after the end of the oxidation process. A variant of the method is also proposed.EFFECT: invention is aimed at increasing the leaching efficiency of sulfide-containing mineral raw materials by providing preliminary formation of readily soluble oxidized forms of the raw materials.10 cl, 6 dwg

Description

The invention relates to the field of mining and, in particular, to the integrated development and use of mineral deposits.

Known methods of underground leaching of metals, providing for borehole leaching from the surface with various methods of impact on the mountain range (Abdulmanov I.G., Brovin K.G., Laverov N.P. and others. Underground leaching of polyelement ores. Publishing house of the Academy of Mining Sciences, Moscow , 1998, p. 115, p. 388; Handbook of geotechnology of Uranus / [V. I. Beletsky and others] // Edited by D. I. Skorovarov. - M.: Energoatomizdat, 1997. - 672 p. . 486). These methods, despite the wide possibilities for the implementation of chemical, biochemical reactions and hydrodynamic processes, are of limited use in the deposits of rock ores due to the absence or low permeability of rock ores for solutions and gases.

There are known methods of underground mine leaching and block underground leaching of rock ores, devoid of the disadvantages of borehole leaching from the surface (Lunev L.N. Mine systems for the development of uranium deposits by underground leaching. M., Energoizdat, 1982; Mosinets V.N., etc. Construction and operation of underground leaching mines. M., Nedra, 1987, p. 53-110). With such methods of block underground leaching during the development of mineral deposits, to supply leaching solutions to the block of collapsed ores, descending irrigation wells are drilled into the upper part of the ore stored in the block through an overhead pillar left above the workings of the collecting horizon (see, for example, SU 705819), or the leaching solution is fed into the magnetized ore through the drilled rising injection wells mixed with air in the hydrodynamic cavitation mode (see RU 2506423 C1). In this case, the wells are drilled for the ore, and the pillar of the ore, in which the injection wells are drilled, is left in place in the form of losses, which is a natural way to preserve the integrity of the mining technical structure. In other cases, most often, the solution is supplied in the mode of irrigation or injection from above. The leaching blocks are affected by various external energy influences, gases, hydrodynamic regimes are changed, etc. (see, for example, RU 2247834 C1).

The disadvantages of the methods described in the literature are their high environmental hazard due to the risk of uncontrolled and, especially, mass leakage of solutions outside the underground leaching blocks, hence, drainage of solutions into the environment (Ivanov V.G., Kamnev E.N., Smagin A. P. A set of measures for the prevention and control of environmental pollution // in the Book. Physico-chemical geotechnology of uranium in rock deposits. M .: Atomnaya energetika, 2009, p. 28). In addition, the disadvantage is that block leaching entails huge losses of valuable components, since the block of leached ore is surrounded by enclosing rocks containing valuable components and ores, which are a natural limiter of blocks of blasted rock mass, and the volume of enclosing ores and rocks reaches 60% of the volume of leached ores.

The known method of combined mining of ores (RU 2361077 C1, publ. 10.07.2009), which includes the extraction of rich ore and the leaching of metals from the rest of the ore at the place of its occurrence. Extraction of high-grade ore is carried out according to the chamber-pillar scheme. Formed primary chambers are formed with geometrical parameters of 10 x 10 m (when working out veins - 2 x 5 m) smaller than those of pillars. The chambers are filled with a hardening mixture, and the space formed by the subsequent excavation of the pillars is filled with a disintegrated ("dry") filling consisting of the tailings of sorting and / or beneficiation of high-grade ore and ordinary ore obtained when driving preparatory and grooved workings. Blasting of the remaining ordinary ore is carried out, and the leaching of metals from the ordinary ore and filling materials is carried out in two stages: at the first - mine waters saturated with air oxygen with the supply of strains of thionic bacteria to them, and at the second - with solutions of the main activated leaching reagents. The disadvantages of this technical solution include the need to leach lumpy ores prepared for explosive leaching. It is known that for effective leaching, the size of the raw material must be minimal, and in the case of underground leaching of rock ores, the presence of more than 15-20% of the 200-150 mm class in the chipped ore can in some cases sharply deteriorate the quality indicators of production and increase the cost of finished products to the boundaries of its full unacceptability (see VK Bubnov and others. Topical issues of extraction of non-ferrous, rare and noble metals. Akmola, 1995. - p. 187).

There is a known method of underground leaching of useful components from raw materials (RU 2429303 C2, publ. 09/20/2011), which provides for sealing the chamber before creating conditions in it similar to the autoclave leaching mode, laying pipelines in the chamber space for supplying air and water under pressure, loading the raw materials and autoclave leaching of such raw materials. Moreover, the autoclave mode of leaching of the backfill raw materials and the increased pressure of the leaching solution in the backfill from the raw material, maintained for the required time by closing the valves of the nozzles, is carried out without the consumption of energy carriers. The disadvantages of this method include the limited scope of its application - only when developing small ore deposits with low-productivity mining systems with ore shrinking, systems of sublevel drifts, etc., since with chamber systems for the development of medium and large ore deposits, access to the spent chambers for their sealing and laying pipelines is not possible due to the risk of death of workers and loss of equipment and is prohibited for safety reasons. The disadvantages of the method also include the need for manual installation of injection pipelines and nozzles under the roof of the chamber, which creates obstacles for uniform air supply to the array according to the top-down scheme, as well as the risk of losing the pipeline network when leaching sulphide ores due to their self-heating to temperatures of 900 ⁰ C and above. The disadvantages of the invention include high costs for sealing underground chambers.

The closest to the proposed method in technical essence and the achieved result is a method for leaching pellets obtained from tailings, which is part of the method for the integrated development of polymetallic ore deposits (RU 2327873 C1, publ. 27.06.2008 - prototype), according to which ore is extracted from chambers of the first stage and process it to obtain concentrate and tailings, tailings are processed into pellets, two technological streams are formed from the resulting pellets, the first stream of pellets is subjected to heap leaching, the second stream of pellets is maintained until the required mechanical characteristics are set, after the leaching process is completed, the pellets of the first technological flow is mixed with a binder and water to obtain a filling mixture, which is sent to the chambers of the first stage before they are filled, after the filling mixture has solidified, ore is removed from the chamber of the second stage, strengthening and preparation of the bottom of this chamber is solid The bottom of the chamber of the second stage is drilled with a system of wells for collecting and circulating solutions with a mixture prepared on the basis of heap leaching waste, pellets of the second process stream are fed into the chamber of the second stage, and the subsequent in situ leaching of the said pellets is carried out by sprinkling them with a solution for leaching and removing the productive solution, and after the completion of leaching, the filling mixture is added to the second stage chamber until the chamber is filled.

The disadvantage of this method is that it does not imply leaching of ores, but is focused on leaching readily soluble granules from the tailings, therefore, the method does not provide for the supply of gases to the array to control the processes of bacterial and oxygen oxidation of sulfides, without which the leaching of metals from sulfide ores is impossible [A Review on Novel Techniques for Chalcopyrite Ore Processing / Alafara A. Baba // International Journal of Mining Engineering and Mineral Processing 2012, 1 (1): 1-16. DOI: 10.5923 / j.mining.20120101.01; Rodrı´guez Y. New information on the pyrite bioleaching mechanism at low and high temperature // Hydrometallurgy, 2003.- V.71, pp. 37-46 doi: 10.1016 / S0304-386X (03) 00172-5]. The disadvantage of the prototype method is also that it does not provide for the removal of gases released during the leaching of sulfides.

The technical problem of the invention is to expand the range of technological capabilities of the in-situ leaching process of sulfide-containing mineral raw materials by providing the possibility of leaching crushed sulfide ores of any size and material composition, substandard sulfide ores, mining and processing waste of sulfide ores.

The technical result, which allows to solve the specified problem, consists in increasing the efficiency of leaching of sulfide-containing mineral raw materials by providing preliminary formation of readily soluble oxidized forms of said raw materials.

The technical result is achieved by the fact that in the method of underground leaching of metals from sulfide-containing mineral raw materials according to the first option, which consists in the fact that in the reactor chamber, which is formed by the extraction of ore and the walls of which are formed by a solidified backfill, the bottom is erected from the backfill mixture, the raw material is loaded into the reactor chamber is drilled in the erected bottom of the well to remove the productive solution, irrigate the raw material from above with a solution for leaching and withdraw the productive solution through the wells in the bottom, according to the invention, after loading the raw material, it is pre-drilled in the erected bottom of the well to supply the oxidizing gas, after which preliminary oxidation is carried out raw material with oxidizing gas in a high-temperature mode in the temperature range from 200 to 900 ° C, while oxidizing gas is supplied through the corresponding wells in the bottom and exhaust sulfur-containing gases are removed from the upper part of the chamber, and drilling in the erected bottom of the wells to remove the productive solution was are formed after the end of the oxidation process.

The technical result is also achieved by the method of underground leaching of metals from sulfide-containing mineral raw materials according to the second option, which consists in the fact that in the reactor chamber, which is formed by the extraction of ore and the walls of which are formed by the solidified backfill, the bottom is erected from the backfill mixture, the raw material is loaded into the reactor chamber , are drilled in the erected bottom of the well to remove the productive solution, irrigate the raw material from above with a solution for leaching and withdraw the productive solution through the wells in the bottom, characterized in that after loading the raw material, wells are also drilled in the bottom to supply oxidizing gas and wells to remove excess solutions, after which is carried out preliminary oxidation of the raw material with an oxidizing gas in a low-temperature mode in the temperature range from 30 to 90 ° C, while the oxidizing gas is supplied through the corresponding wells in the bottom, at the same time the leaching solution is fed from above with additives that intensify the oxidation process, while providing the intensity of the solution supply is sufficient to saturate the feedstock and the oxidation process, and the exhaust sulfur-containing gases are removed from the upper part of the chamber and the excess solutions are removed through the corresponding wells, and the active irrigation of the feedstock from above with a leaching solution and the withdrawal of the productive solution is carried out after the end of the oxidation process.

In both variants of the method, crushed sulfide-containing ore, or substandard sulfide-containing ore, or its mining waste, or its processing waste, is used as a sulfide-containing mineral raw material.

In this case, an oxygen-containing gas, in particular air, is used as the oxidizing gas.

In addition, the supply of irrigation solutions is carried out through nozzles installed in the entrance of the overlying horizon.

In addition, the removal of sulfur-containing gases is carried out through a pipeline located at the entrance of the overlying horizon.

The proposed method ensures the involvement in the development of reserves of sulfide ores, previously referred to as off-balance, the creation of conditions for the oxidation of sulfide minerals - setting the size necessary for leaching, generating heat and developing bacteria, uniform supply and capture of gases and solutions.

This approach allows loading crushed sulfide ores of any size and material composition into the chamber of the second stage - the reactor chamber, providing heat generation due to natural self-heating of sulfide ores, creating conditions for the development of microorganisms that intensify oxidation processes, and ensuring a uniform supply of gases from below throughout areas of the crushed ore massif, irrigation and collection of working solutions.

The essence of the invention is illustrated by drawings.

FIG. 1 shows a cross-sectional view of an ISLR chamber.

FIG. 2 - parameters of high-temperature oxidation, characterizing the dependence of the weight loss of pyrite ores Δm,% on the oxidation temperature in the reactor chamber.

FIG. 3 - leaching parameters after high-temperature oxidation of mixed copper-pyrite ore, characterizing the dependence of the weight loss of the investigated roasted fractions on temperature in the range from 100 ° C (control) to 900 ° C after contact with distilled water and sulfuric acid solution with pH = 1.5 ...

FIG. 4 - leaching parameters after high-temperature oxidation of copper-pyrite ore for 2.5 hours, characterizing the dependence of the copper content on temperature.

FIG. 5 is a graph of the dependence of the copper content in the productive solution from the time of leaching after low-temperature oxidation.

FIG. 6 is a graph of the dependence of the zinc content in the productive solution on the time of leaching after low-temperature oxidation.

The method of underground leaching of metals from sulfide-containing mineral raw materials is carried out as follows

The development of a mineral deposit is carried out by the underground method with chamber development systems with the backfilling of the worked-out space in two or more stages (through the pillar). After the chambers of the first stage are removed, they are laid with a hardening backfill, while pillars are erected on the basis of backfill concrete, which in the future will be the walls of the reactor chambers. After ore is extracted from the chambers of the second stage, in the lower part of these chambers, jumpers are installed to prevent the spreading of the filling mixture along the workings. After installing jumpers in the second stage chamber - the reactor chamber - a reinforced bottom is erected by feeding the filling mixture into the reactor chamber from top to bottom from the ramps of the overlying horizon.

The chamber-reactor for in-situ leaching includes walls 1 based on a hardening mixture, a hardened bottom 2 based on a hardening mixture, drilled with fans of wells 5 for supplying oxidizing gas and removing solutions.

After the set with a reinforced bottom of the standard strength, the reactor chamber is loaded with raw materials for leaching, pouring the raw materials also from top to bottom through inlets 3. Thus, a leached massif 4 is formed from ores or their mining and processing waste. In the future, the method is implemented according to an algorithm that depends on the required preparatory leaching regime, these are:

- high-temperature oxidation (first option);

- low-temperature oxidation (second option).

In the leaching method according to the first embodiment with high-temperature oxidation, before its implementation, wells 5 are drilled in the erected bottom 2 of the reactor chamber to supply an oxidizing gas, mainly oxygen-containing gas (in particular, air). Wellheads 5 or wells 5 are completely cased with pipes suitable for contact with oxygen-containing gas. Oxygen-containing gas is supplied through a pipeline system located in the passages 6 of the underlying horizon and wells 5, reaching the required degree of ore oxidation. The capture of the exhaust sulfur-containing gases in the course of active oxidation is carried out in the passages 3 of the overlying horizon. To do this, in races 3, a jumper is installed with an opening, into which a pipeline cuts in to remove gases that are processed to produce sulfuric acid.

In the future, the obtained sulfuric acid is used for underground leaching of the same ores, or raw materials located in adjacent already prepared chambers. After the cessation of active high-temperature oxidation, the bottom 2 of the reactor chamber is additionally covered with systems of wells 5 for collecting solutions, and the overlying horizon through the arrivals 3 is equipped with a system for supplying solutions to the reactor chamber from above according to the same principle as the exhaust of gases, but nozzles are cut into the jumper for spraying solutions.

After preparation of the irrigation system and collection of solutions, active leaching of previously oxidized raw materials, represented by readily soluble mineral forms, is carried out. In this case, the operation of the chamber-reactor is continuous and continues until the required oxidation state of minerals and phase transitions are reached.

от исходной массы пробы, свидетельствующую об интенсивности фазовых переходов, а также показывающую, какое количество отходящего газа необходимо улавливать при работе камер-реакторов. На фиг. 2 представлена зависимость убыли массы Δm, % от температуры окисления.In laboratory experiments, the process of high-temperature oxidation was simulated. For this purpose, mixed copper-pyrite ores were roasted in the presence of atmospheric oxygen at temperatures from 200 to 900 ⁰ С in increments of 100 ⁰ С. Thus, 8 batches of mixed ores were studied. During high-temperature oxidation under model conditions, the decrease in the mass of the mineral substance was recorded

from the initial mass of the sample, indicating the intensity of phase transitions, and also showing how much of the exhaust gas must be captured during the operation of the chamber-reactors. FIG. 2 shows the dependence of the weight loss Δm,% on the oxidation temperature.

Experiments have shown that when an oxidizing gas, mainly containing oxygen, is supplied from below, efficient oxidation of the ore with the formation of readily soluble oxidized forms is possible in the reactor chambers.

After the completion of the high-temperature oxidation, each of the 8 samples was leached. To do this, a sulfuric acid solution with pH = 1.5 and, for comparison, water were passed through the oxidized ore for 2.5 hours. After leaching, the ore was dried, weighed, and the weight loss was determined. It was found that for ores oxidized at temperatures up to 800 ⁰ C, the weight loss reaches 12%, which indicates good solubility (Fig. 3). In this case, the solutions are very saturated with respect to copper - the metal content reaches 1.2 g / dm ³ (figure 4), respectively, is industrial. Such solutions can be efficiently processed by any hydrometallurgical method with metal recovery. If the solutions supplied through the systems of wells 5 for collecting solutions do not have an industrial content of metals sufficient for processing, the collected solutions are fed through the pipeline system again for irrigation of ore raw materials in a cyclic mode. Before this, the chemical composition of the leaching solutions is checked and, if necessary, adjusted to regulatory requirements.

In the second variant of the method of leaching with low-temperature oxidation, after loading the raw material into the chamber-rector, wells 5 are drilled in the erected bottom 2 to supply oxidizing gas to the array and to collect excess solutions. Wells 5, or only wellheads are cased. The reactor chamber is fed:

- from below, through wells 5 drilled in the bottom 2 - the required amount of oxidizing oxygen-containing gas, mainly air. Possible or preferable supply of compressed air from the general mine network of compressed air;

- on top - a solution for leaching, containing intensifying chemical or biochemical additives (strains of bacteria, archaea, etc.), contributing to the intensification of the leaching process, or a complex of intensifying methods of exposure is carried out.

The temperature and intensity of the supply of oxidizing gases into the array of oxidized raw materials, as well as the temperature of the supplied solution are determined by the requirements for the course of chemical reactions, or for ensuring the normal vital activity of microorganisms in an aerobic or anaerobic mode (regulated simultaneously - by supplying gases from below and solutions from above). The solution is served in a limited drip mode in an amount sufficient to saturate the oxidized raw material with it. Excess solution is discharged through wells 5 to remove excess solutions. The fact is that even with drip irrigation, limited mode, a certain amount of solutions will flow through the bottom almost immediately, so it is necessary to remove excess solutions.

Low-temperature oxidation is carried out. Moreover, it is taken into account that, due to the duration of low-temperature oxidation, the operation of the chamber-reactor can be carried out in a discrete mode. Periodically, such technological processes can be carried out as: heating solutions, washing the ore mass, supplying solutions of a different chemical composition for dissolving passivating films, supplying cultures of microorganisms, supplying oxidizing gases, supplying hot gases, supplying other gases.

After prolonged low-temperature oxidation, sulfides pass mainly into secondary sulfides and sulfate forms, which are readily soluble. After such phase transitions of minerals into readily soluble forms, leaching is carried out in the operating mode of active leaching, as described above.

In the course of simulating the process of low-temperature oxidation of mixed copper-zinc ores in laboratory conditions, the mechanism of low-temperature oxidation was investigated by feeding an acidifying solution from above and entering air from below through an array of mixed copper-zinc ores. At the same time, the temperature in the climatic chamber was maintained similar to the temperature range of low-temperature oxidation - about 60 ⁰ C. The pre-oxidation solution containing the chemical reagent was fed in a limited drip mode from the top, and air was fed into the loaded ore massif from the bottom.

After preliminary oxidation, which lasted for 20 days, leaching began with a solution having a sulfuric acid reaction at pH = 2. It was proved that the copper content in the solution for 20 days was at the level from 5800 to 2000 g / dm ³ , zinc - from 19500 up to 13500 g / dm ³ (Fig. 5, 6).

After the cessation of leaching, the chamber-reactor is either added under the roof with a hardening mixture and thus preserved or unloaded. In the latter case, the bottom is blasted and the waste is extracted after leaching, and boreholes drilled earlier for supplying gases and collecting solutions are used to place explosive charges in the bottom.

In special cases, the chamber-reactor is filled with intra-mine separation waste obtained on the basis of an express assessment of the chemical composition of ores in a bucket of mining transport machines, or on high-speed belt separators. It is also possible to fill the reactor chamber with pelletized enrichment wastes or other permeable to gases and solutions of mineral substances.

Claims (10)

1. The method of underground leaching of metals from sulfide-containing mineral raw materials, which consists in the fact that in the reactor chamber, which is formed by the extraction of ore and the walls of which are formed by the hardened backfill, the bottom is erected from the filling mixture, the raw material is loaded into the reactor chamber, drilled in the erected bottom wells for withdrawing the productive solution, irrigate the raw material from above with a solution for leaching and withdraw the productive solution through the wells in the bottom, characterized in that after loading the raw material, they are pre-drilled in the erected bottom of the well to supply the oxidizing gas, after which the raw material is pre-oxidized with oxidizing gas in a high-temperature mode in the temperature range from 200 to 900 ° C, while the oxidizing gas is supplied through the wells to supply the oxidizing gas and the exhaust sulfur-containing gases are removed from the upper part of the chamber, and drilling in the erected bottom of the wells to remove the productive solution is carried out after the oxidation process is completed. 2. A method according to claim 1, characterized in that crushed sulfide-containing ore, or substandard sulfide-containing ore, or its mining wastes, or its processing wastes are used as sulfide-containing mineral raw materials. 3. A method according to claim 1, characterized in that an oxygen-containing gas, in particular air, is used as the oxidizing gas. 4. The method according to claim. 1, characterized in that the supply of solutions for irrigation is carried out through nozzles installed at the entrance of the overlying horizon. 5. The method according to claim 1, characterized in that the removal of sulfur-containing gases is carried out through a pipeline located at the entrance of the overlying horizon. 6. The method of underground leaching of metals from sulfide-containing mineral raw materials, which consists in the fact that in the reactor chamber, which is formed by the extraction of ore and the walls of which are formed by the hardened fill, the bottom is erected from the filling mixture, the raw materials are loaded into the reactor chamber, drilled in the erected bottom wells to drain the solution, irrigate the raw material from above with a solution for leaching and withdraw the productive solution through the wells in the bottom, characterized in that after loading the raw material, wells are drilled in the erected bottom for supplying oxidizing gas and wells for removing excess solutions, after which preliminary oxidation of the raw material is carried out oxidizing gas in a low-temperature mode in the temperature range from 30 to 90 ° C, while the oxidizing gas is supplied through the corresponding wells in the bottom, at the same time the leaching solution is fed from above with additives that intensify the oxidation process, while the intensity of the solution supply is sufficient to saturate the feedstock and flowthe oxidation process, and exhaust sulfur-containing gases are removed from the upper part of the chamber and excess solutions are removed through the corresponding wells, and the irrigation of raw materials from above with a solution for leaching and removal of the productive solution is carried out after the end of the oxidation process. 7. The method according to claim 6, characterized in that crushed sulfide-containing ore, or substandard sulfide-containing ore, or its mining wastes, or its processing wastes are used as sulfide-containing mineral raw materials. 8. A method according to claim 6, characterized in that an oxygen-containing gas, in particular air, is used as the oxidizing gas. 9. The method according to claim 6, characterized in that the supply of irrigation solutions is carried out through nozzles installed in the entrance of the overlying horizon. 10. The method according to claim 6, characterized in that the removal of sulfur-containing gases is carried out through a pipeline located at the entrance of the overlying horizon.

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