RU2712160C1 - Method of processing sulphide concentrates containing pyrrhotine, pyrite, chalcopyrite, pentlandite and precious metals - Google Patents

Abstract

FIELD: metallurgy.SUBSTANCE: invention relates to non-ferrous metallurgy, particularly, to hydrometallurgical processing of sulphide concentrates containing non-ferrous metals, iron and precious metals. Processing of sulphide concentrates containing pyrrhotine, pyrite, chalcopyrite, pentlandite and precious metals includes autoclave oxidative leaching of initial sulphide concentrate, processing of residual leaching according to burning-chlorination scheme and extraction of precious metals from chlorination solutions. Content of basic elements in initial sulphide concentrate is within following limits: nickel – 0.5–10 %, copper – 0.5–10 %, iron – 5–35 %, sulfur – 5–30 %, sum of precious metals – not less than 30 g/t.EFFECT: high extraction of non-ferrous and precious metals.5 cl, 2 dwg, 8 tbl, 6 ex

Description

The invention relates to non-ferrous metallurgy, in particular to hydrometallurgical methods for processing sulfide concentrates containing non-ferrous metals, iron and precious metals.

A known method of hydrometallurgical processing of pyrrhotite concentrates, including autoclave oxidative leaching (AOB) of a material with the conversion of sulfur into elemental, non-ferrous metals into solution, iron into oxides at a temperature above the melting point of elemental sulfur under the pressure of oxygen in the presence of surface-active substances (surfactants), deposition non-ferrous metal sulfides from a solution of oxidized pulp with elemental sulfur and metallized iron powder, followed by the separation of sulfides and sulfur by flotation in sulfur sulfide concentrate, and iron oxides in tailings. This method was industrially implemented at the Nadezhda Metallurgical Plant in the ZF of OJSC TMK Norilsk Nickel (S. S. Naboyuchenko, L. P. Ni, Ya. M. Shneerson, L. V. Chugaev. Non-ferrous autoclave hydrometallurgy. Yekaterinburg, 2002 , pp. 419-422). The disadvantage of this method is the low extraction of non-ferrous and precious metals in the sulfide concentrate and the inability, in this regard, to process according to this option pyrrhotite-pentlandite concentrates with a high content of nickel and precious metals.

Also known is a method of hydrometallurgical processing of sulfide pentlandite-pyrrhotite feedstock (RF Patent 2626257), including autoclave oxidative leaching of the initial concentrate at a temperature of 90-105 ° C and a partial oxygen pressure in the range from 0.5 to 1.5 MPa. Sulfuric acid (100-200 kg / t conc.) And sodium sulfate (130-230 kg / t conc.) Are supplied to the oxidative leach operation of the concentrate. Reagent costs depend on the composition of the initial pyrrhotite - pentlandite concentrate. The pulp oxidized as a result of leaching is sent to countercurrent washing, as a result of which a metal-containing solution is formed, which is sent for processing, and a solid phase washed from water-soluble compounds of non-ferrous metals. The solid phase is sent to flotation, during which a sulfur sulfide concentrate and tailings of dump quality are formed, in which 5.8-16.0% of precious metals (DM) are extracted. The technology is applicable for the processing of ore pentlandite-pyrrhotite concentrates with a wide range of nickel and DM contents: Ni - 0.7-8.72%, DM - more than 2.2 g / t. The disadvantage of this method is the reduced extraction of precious metals in the target product of the technology in comparison with the pyrometallurgical options for processing sulfide concentrate.

Closest to the proposed method, which is selected as the closest analogue, is a method of hydrometallurgical processing of sulfide flotation concentrate in order to extract platinum group metals. (US Pat. No. 6,579,504). The specified method of hydrometallurgical processing of sulfide concentrate includes the following stages:

- autoclave oxidative leaching of flotation concentrate;

- separation of the leach solution from the solid residue;

- firing the leach residue;

- chlorination of the cinder in order to transfer the platinum group metals into solution;

- adsorption of platinum group metals on an ion-exchange resin;

- the extraction of platinum group metals from the ion exchange resin and the separation of precious metals concentrate.

The autoclave oxidative leaching operation is carried out at the following parameters: temperature - 150 ° C, oxygen partial pressure - 1.0 MPa, liquid to solid ratio in the initial pulp - 3, operation duration - 1.5 hours. In the autoclave leaching operation, the maximum oxidation of sulfur contained in the initial concentrate and the maximum transfer of non-ferrous metals to solution occur: 93-96% nickel and more than 70% copper. It was shown that the transition to the solution of metals of the platinum group is small - 2-2.5% of the amount of metal in the initial concentrate, while the degree of transition to the solution of platinum and palladium is less than 0.5%.

The firing of the autoclave leach residue is carried out at temperatures up to 1000 ° C. The cinder is processed into two-stage countercurrent chlorination operations. The chlorination operation occurs at the following parameters: temperature 85-90 ° C, the ratio of liquid to solid in the initial pulp is 3, the initial concentration of hydrochloric acid is 170 g / l, the redox potential is 950-1050 mV, the duration of the operation is 2-2, 5 hours The conditions of the chlorination process provide the following extraction of precious metals from the cinder into the solution: platinum - 99%, palladium 92%, rhodium - 84%, ruthenium - 90%, iridium - 90%, gold - 95%.

In accordance with the description of the method, the closest analogue is applicable for sulfide concentrates of the following composition,%. g / t (for DM): Ni - 1.04-3.11; Cu 0.62-2.07; Co - 0.023-0.073; Fe - 7.9-12.4; S - 1.72-7.09; Pt - 156-572; Pd 74.7-289; Rh 26.3-106; Ru - 52.7-155; Ir - 0.59-39; Au - 1.91-5.6, the amount - 312.2-1166.6. Thus, the method - the closest analogue to the processing of sulfide concentrates is applicable for low-sulfide materials with a low sulfur content of 1.72-7.09% and a high content of precious metals: the amount of DM is 312.2-1166.6 g / t. The method is the closest analogue provides high extraction of precious metals in the final concentrate, but has limited applicability, which is its significant drawback.

The present invention is aimed at eliminating the specified disadvantage of the closest analogue by implementing the following measures:

- The choice of the optimal leaching mode of the initial sulfide concentrate depending on the composition of the initial concentrate.

- Carrying out additional operations for processing the remainder of the autoclave oxidative leaching, in the case of a high content of elemental sulfur in it (more than 5-10%). Additional operations are as follows: the remainder of the autoclave oxidative leaching is directed to the operations for the separation of elemental sulfur by known methods (sulfur sulfide flotation, disintegration of sulfur sulfide flotation concentrate, sulfur flotation and autoclave sulfur smelting) to obtain tailings of sulfur sulfide flotation sent to the operations of sulfur sulfide chlorination, concentrate sent to the second stage of autoclave oxidative leaching, which is carried out at a temperature re 150-200 ° C and a partial oxygen pressure of 0.3-1.0 MPa. The remainder of the second stage of autoclave oxidative leaching is combined with the sulfosulfide flotation tailings.

- Selection of the optimal scheme for processing solid residue containing precious metals for firing - chlorination operations in order to increase the extraction of precious metals into solution during processing of the initial sulfide concentrate with a precious metal content of at least 30 g / t.

The initial concentrate of the proposed method may contain various sulfide minerals: pentlandite, chalcopyrite, pyrrhotite, pyrite. Depending on the ratio of sulfide mineral contents in the initial concentrate, the parameters of the head operation of the technology - autoclave oxidative leaching, and the composition of the solid leach residue sent for further processing change. With an increased content of chalcopyrite and pyrite in the initial sulfide concentrate, the main task of autoclave oxidative leaching (maximum oxidation of sulfides and maximum transfer of non-ferrous metals (CM) to solution) is achieved by increasing the process temperature to 160-200 ° C. With an increased content of pyrrhotite in the initial sulfide concentrate, the process of oxidative leaching proceeds with the formation of significant amounts of elemental sulfur. The formation of elemental sulfur during leaching leads to the risk of the formation of sulfosulfide conglomerates, resulting in a decrease in the oxidation state of sulfide minerals and damage to autoclave equipment. In order to prevent the formation of sulfur sulfide conglomerates, the autoclave oxidative leaching operation is carried out with the addition of surface-active substances (surfactants), for example, lignosulfonate, which prevents the coalescence of molten sulfur and its wetting of sulfide particles at a temperature of not more than 150 ° C. The effectiveness of the use of surfactants decreases with increasing leaching temperature of more than 150 ° C, which limits the parameters of the leaching process.

The proposed autoclave oxidative leaching regime allows the processing of sulfide concentrates with a high content of pyrrhotite. In this case, the leach residue contains significant amounts of elemental sulfur (10-20%) and significant amounts of non-oxidized nickel sulfides, and especially copper. Processing the leach residue with a high content of elemental sulfur according to the roasting-chlorination scheme is impractical due to the formation of significant amounts of sulfur dioxide during the roasting process. In order to prevent the formation of sulfur dioxide in accordance with the proposed method, the leach residue before the firing operation is sent to the separation of elemental sulfur by known methods. First, the leach residue is sent to the operation of sulfosulfide flotation (SSF) to obtain tailings of sulfurosulfide flotation, sent for roasting-chlorination, and sulfur-sulfide flotation concentrate. Sulfur concentrate is sent to the operations of disintegration and sulfur flotation to obtain sulfide and sulfur flotation concentrates. Sulfur flotation concentrate is sent to the autoclave sulfur smelting operation to obtain elemental sulfur and sulfur smelting tails returned to the sulfur flotation operation. The secondary sulfide flotation concentrate is sent to the second stage of the autoclave oxidative leaching to leach copper and nickel sulfides not decomposed in the first stage, which is carried out at a temperature of 150-200 ° C and a partial oxygen pressure of 0.3-1.0 MPa. The remainder of the second stage of autoclave oxidative leaching is combined with the tailings of sulfur-sulfide flotation and sent to the firing-chlorination operation.

The proposed method allows to achieve high extraction of precious metals into the final product during the processing of sulfide concentrates with a wide range of contents of non-ferrous metals, iron and sulfur: nickel - 0.5-10%, copper - 0.5-10%, iron - 5-35% , sulfur - 5-30%.

The claimed technical result is achieved by the fact that in the method of processing sulfide concentrates containing pyrrhotite, pyrite, chalcopyrite, pentlandite and precious metals, including autoclave oxidative leaching of the initial sulfide concentrate, processing the leach residue according to the calcination-chlorination scheme, the extraction of precious metals from chlorination solutions by known methods , according to the proposed method, depending on the content of pyrite and pyrrhotite in the initial concentrate, the head mode changes autoclave oxidative leaching, and before processing the leach residue according to the roasting-chlorination scheme, it can be further processed, which consists in the separation of elemental sulfur and the oxidation of undecomposed sulfides of copper and nickel.

The claimed technical result is also achieved by the fact that the processing of sulfide concentrates containing precious metals and an increased amount of pyrite (more than 10%), regardless of the content of pentlandite and chalcopyrite, is implemented according to the scheme shown in FIG. 1 and including the following technological operations:

- high temperature autoclave oxidative leaching;

- pulp dehydration and leaching of the leach residue;

- extraction of non-ferrous metals from the production solution of dehydration by known methods;

- processing the leach residue according to the roasting-hydrochlorination scheme;

- sorption of precious metals from a hydrochlorination solution;

- the allocation of the concentrate of precious metals by known methods (desorption and precipitation of precious metals or burning of an ion exchange resin).

The autoclave oxidative leaching operation is carried out in high temperature mode at a temperature of 160-200 ° C and a partial oxygen pressure of 0.3-1.0 MPa. The flow diagram of the processing of sulfide concentrates with a high content of pyrite is shown in FIG. 1.

The claimed technical result is also achieved by the fact that the processing of sulfide concentrates containing precious metals and an increased amount of pyrrhotite (more than 10%), regardless of the content of other sulfide minerals (pyrite, chalcopyrite, pentlandite), is implemented according to the scheme shown in FIG. 2 and including the following technological operations:

- autoclave oxidative leaching;

- pulp dehydration and leaching of the leach residue;

- extraction of non-ferrous metals from the production solution of dehydration by known methods;

- processing of the leach residue by known methods (sulfur sulfide flotation, disintegration of sulfur sulfide flotation concentrate, sulfur flotation and autoclave sulfur smelting) to obtain tailings of sulfur sulfide flotation, elemental sulfur and secondary sulfide concentrate,

- high temperature autoclave oxidative leaching of secondary sulfide concentrate;

- pulp dehydration and leaching of the leach residue;

- processing of tailings of sulfur-sulfide flotation and the residue of leaching of the secondary sulfide concentrate according to the roasting-hydrochlorination scheme;

- sorption of precious metals from a hydrochlorination solution;

- the allocation of the concentrate of precious metals by known methods (desorption and precipitation of precious metals or burning of an ion exchange resin).

The autoclave oxidative leaching of the initial concentrate is carried out at a temperature of not more than 150 ° C and a partial oxygen pressure of 0.3-1.0 MPa. The operation of the autoclave oxidative leaching of the secondary sulfide concentrate is carried out at a temperature of 150-200 ° C and a partial oxygen pressure of 0.3-1.0 MPa. The flow chart of the processing of sulfide concentrates with a high content of pyrrhotite is shown in FIG. 2.

The claimed technical result is also achieved by the fact that in order to increase the recovery of precious metals and, first of all, palladium into the chlorination solution, the remainder of the high-temperature autoclave oxidative leach and the tailings of sulfur-sulfide flotation are processed according to the following scheme: the remainder of the autoclave oxidative leach and tailings of sulfur-sulfide flotation are sent to the first stage chlorination, the remainder of the first stage of chlorination is sent for firing at a temperature of 900-1100 ° C, and the cinder is sent to the second stage of chlorination with obtaining a working solution of chlorination and dump solid residue.

Thus, the proposed method for processing sulfide concentrates containing non-ferrous metals, iron and precious metals is illustrated by the following technological schemes (drawings):

- in FIG. 1 presents a flow chart of the processing of sulfide concentrates with a high content of pyrite;

- in FIG. 2 presents a flow chart of the processing of sulfide concentrates with a high content of pyrrhotite.

The method is illustrated by examples in which the following sulfide concentrates were used as feedstock:

- Sulfide concentrate (hereinafter K1). Composition (% or g / t for precious metals on dry weight): nickel - 1.83; copper - 4.22; iron - 27.2; sulfur - 18.3; platinum - 10; palladium - 26.5; the amount of DM - 40.0. The pyrite content is 13.9%, the pyrrhotite content is 9.5%.

- Sulfide concentrate (hereinafter K2), composition (% or g / t for precious metals on dry weight): nickel - 4.19; copper - 8.15; iron - 42.8; sulfur - 35.3; platinum - 20.0; palladium - 66.0; the amount of DM - 93.65. The pyrite content is 8.4%, the pyrrhotite content is 45.2%.

Example 1. (Experiments in the closest way). The experiments were carried out in a 1 liter autoclave with mechanical stirring. Leaching conditions: temperature 150 ° C; rotation speed of the turbine mixer - 1500 min ^-1 ; partial oxygen pressure of 1.0 MPa; W: T of the initial pulp - 3; leaching time 90 min. Concentrates K1 and K2 were used as initial concentrates.

At the end of leaching, the resulting slurry was filtered, and the leach residue was washed on the filter with water. The conditions and results of the experiments are shown in tables 1 and 2.

The leaching process of sulfide concentrate K1 with a high pyrite content (more than 10%) according to the closest method is characterized by insufficiently high rates of extraction of non-ferrous metals into the solution and the degree of decomposition of pyrite.

The leaching process of K2 sulfide concentrate with a high content of pyrrhotite (more than 10%) according to the closest method is characterized by the formation of sulfosulfide conglomerates.

Example 2. (Experiments on the proposed method). The experiments were carried out in a 1 liter autoclave with mechanical stirring. Leaching conditions: temperature 150-210 ° C; rotation speed of the turbine mixer - 1500 min ^-1 ; partial oxygen pressure of 0.3-1.0 MPa; W: T of the initial pulp - 3; leaching time 90 min. As the initial concentrate, K1 concentrate was used.

At the end of leaching, the resulting slurry was filtered, and the leach residue was washed on the filter with water. The conditions and results of the experiments are shown in table 3.

In the process of leaching a sulfide concentrate with a high content of pyrite (K1), increasing the temperature to 160-200 ° C ensures the maximum extraction of non-ferrous metals in solution and the maximum decomposition of pyrite. A temperature increase of more than 200 ° C does not lead to an increase in leaching rates.

Example 3. (Experiments on the proposed method). The experiments were carried out in a 1 liter autoclave with mechanical stirring. Leaching conditions: temperature 130-170 ° C; rotation speed of the turbine mixer - 1500 min ^-1 ; partial oxygen pressure of 0.5 MPa; W: T of the initial pulp - 3; leaching time 90 min. As the initial concentrate, K2 concentrate was used.

At the end of leaching, the resulting slurry was filtered, and the leach residue was washed on the filter with water. The conditions and results of the experiments are shown in table 4.

The process of leaching a sulfide concentrate with a high content of pyrrhotite (K2) is characterized by the formation of significant amounts of elemental sulfur (the content of AOV in the residue is 15.3-19.2%). The absence of sulfur sulfide granules in the leaching process is provided by the introduction of surfactants (in this example, lignosulfonate). Raising the process temperature to 160-170 ° C, despite the presence of lignosulfonate, leads to the formation of sulfosulfide granules.

Example 4. (Experiments on the proposed method). The raw material for the experiments was selected residue autoclave oxidative leaching obtained in experiment 13 (table 4, example 3). The sulfur sulfide flotation experiments were carried out in a flotation machine with a chamber volume of 0.5 l. The flotation scheme included the stages of the main and control flotation and two stages of purification of the rough concentrate. The solids content in the pulp in the main flotation is 40-45%. The consumption of potassium butyl xanthate (sulfide collector) is 450 g / t.

The experiments on the disintegration of sulfosulfide concentrate were carried out in an autoclave with a volume of 1 dm ³ at a temperature of 130 ° C and a mixing intensity of 600-1000 rpm. The duration of the operation was 1.0 hour, the consumption of caustic soda was 67 kg / t solid. The ratio W / T in the initial pulp was 5. The experiments on sulfur flotation of the disintegration pulp were carried out in a flotation machine with a chamber volume of 0.5 liters. The flotation scheme included the stages of the main and control flotation and the stage of cleaning the rough concentrate. The solids content in the pulp in the main flotation is 40-45%. Diesel fuel consumption (elemental sulfur collector) - 200 g / t.

The experiments on the smelting of sulfur from sulfur concentrate were carried out in a 1 dm ³ autoclave at a temperature of 130 ° C, operation time was 1.0 hour, caustic soda consumption was 80 kg / t solid, diesel fuel consumption was 1.0-1 , 5 kg / t, the ratio W / T in the initial pulp is 1.5.

The leaching experiments on the sulfide flotation concentrate were carried out in a 1 liter autoclave with mechanical stirring. Leaching conditions: temperature 150-200 ° C; rotation speed of the turbine mixer - 1500 min ^-1 ; partial oxygen pressure of 0.3-1.0 MPa; W: T of the initial pulp - 3; leaching time 90 min.

The conditions and results of the experiments are shown in tables 5 and 6.

Example 5. (Experience in the closest way). The experiment was carried out according to the firing - chlorination scheme. The starting material for the experiment was obtained at the stage of high-temperature autoclave oxidative leaching in experiment 6 (table 3, example 2). The firing of the leach residue was carried out at the following process parameters: temperature - 1000 ° C, firing duration - 2 hours, air flow - 300 l / h. The cinder was sent to stage 1 hydrochlorination, which was carried out in the following mode: W / T of the initial pulp - 10; temperature - 90 ° C; the initial content of hydrochloric acid in the solution is 100 g / l; the oxidizing agent is Cl ₂ ; ORP - not less than 1000 mV; duration is 2 hours.

The pulp of the 1st hydrochlorination stage was filtered, the solid residue was washed with water and sent to the 2nd hydrochlorination stage, which was carried out in a similar mode to the 1st stage. At the end of stage 2 of hydrochlorination, the resulting pulp was filtered, the solid residue was washed on the filter with water. The results of the experiment are shown in table 7.

Example 6. (Experience in the proposed method). The experiments were carried out according to the scheme of chlorination - firing - chlorination. The starting materials for the experiment were obtained at the stage of high-temperature autoclave oxidative leaching of concentrate K1 in experiment 6 (table 3, example 2) and according to the processing scheme of concentrate K2 shown in FIG. 2 (tails of the SSF residue AOB (example 4, table 5) and the leach residue (experiment 19, example 4, table 6)). The source material was sent to the 1st stage of hydrochlorination, which was carried out in the following mode: W / T of the initial pulp - 10; temperature - 90 ° C; the initial content of hydrochloric acid in the solution is 100 g / l; the oxidizing agent is Cl ₂ ; ORP - not less than 1000 mV; duration is 2 hours.

The pulp of the 1st stage of hydrochlorination was filtered, the solid residue was washed with water, dried and sent to the firing operation, which was carried out with the following process parameters: temperature - 1000 ° C, firing duration - 2 hours, air flow - 300 l / h. The cinder was sent to stage 2 of hydrochlorination, which was carried out in a mode similar to stage 1.

At the end of stage 2 of hydrochlorination, the resulting pulp was filtered, the solid residue was washed on the filter with water. The results of the experiment are shown in table 8.

A change in the scheme for processing the autoclave leach residue allowed increasing the extraction of palladium into solution from 87.2 to 98.7% and the amount of precious metals from 90.1 to 95.9%.

Claims (5)

1. A method of processing sulfide concentrates containing pyrrhotite, pyrite, chalcopyrite, pentlandite and precious metals, including autoclave oxidative leaching of the initial sulfide concentrate, processing of the leach residue according to the calcination-chlorination scheme, extraction of precious metals from chlorination solutions, characterized in that the content of the main elements in the initial sulfide concentrate is in the following ranges: nickel - 0.5-10%, copper - 0.5-10%, iron - 5-35%, sulfur - 5-30%, the amount of precious metals - not less than 30 g / t 2. The method according to p. 1, characterized in that when the pyrite content in the initial sulfide concentrate is more than 10%, autoclave oxidative leaching is carried out at a temperature of 160-200 ° C and a partial oxygen pressure of 0.3-1.0 MPa. 3. The method according to p. 1, characterized in that regardless of the pyrite content when the content of pyrrhotite in the initial sulfide concentrate is more than 10%, autoclave oxidative leaching is carried out at a temperature of not more than 150 ° C and a partial oxygen pressure of 0.3-1.0 MPa. 4. The method according to p. 3, characterized in that the remainder of the autoclave oxidative leaching is directed to the separation of elemental sulfur by sulfur-sulfide flotation, disintegration of sulfur-sulfide flotation concentrate, sulfur flotation and autoclave sulfur production to obtain tailings of sulfur-sulfide flotation, sent to the roasting chlorination, sulfur and sulfide concentrate sent to the second stage of autoclave oxidative leaching, which is carried out at a temperature of 150-200 ° C and a partial oxygen pressure of 0.3-1.0 MP and, the remainder of the second stage of the autoclave oxidative leaching is combined with the tailings of sulfur sulfide flotation. 5. The method according to one of paragraphs. 1-4, characterized in that the remainder of the high-temperature autoclave oxidative leach and the tailings of sulfur sulfide flotation are processed by chlorination of the remainder of the autoclave oxidative leach and tailings of sulfur-sulfide flotation, then the remainder of the chlorination is calcined at a temperature of 900-1100 ° C, and the cinder is sent to the chlorine for firing chlorination solution and dump solid residue.

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