RU2685621C1 - Method for complex processing of sulphide-oxidised copper-porphyritic ores - Google Patents

Abstract

FIELD: metallurgy.SUBSTANCE: invention relates to metallurgical processes. Result is achieved by complex processing of sulphide-oxidised copper-porphyritic ores, including crushing and subsequent grinding of ore to size of not more than 0.075 mm, flotation and concentration of sulphide minerals of copper, molybdenum and zinc. At that, additional flotation recovery of pyritic concentrate is carried out with subsequent oxidative firing of sulphide concentrates, obtaining sulfuric acid from gases formed at firing, as well as cinder wastes of non-ferrous metals and iron, with subsequent leaching of ash in an aqueous solution of sulfuric acid with acoustic energy of 0.1–1.0 W/cm, by washing and dehydration of cake of concentrate leaching. Further, the liquid phase of the concentrate leaching is combined with the leaching cake leaching water, the combined liquid phase is free from solid suspensions by ultrasonic filtration and the liquid phase is returned to the process.EFFECT: additional extraction of noble, nonferrous, rare and rare-earth metals from pyrite concentrates obtained during processing of copper-porphyritic ores.1 cl, 1 tbl, 3 ex

Description

The invention relates to metallurgical processes, in particular to the processes of complex extraction, along with the main product, valuable components of the enrichment production, including precious, non-ferrous, rare and rare-earth metals from copper, zinc, molybdenum and pyrite concentrates, obtained during the processing of porphyry copper ore

This goal is achieved by complex processing of sulfide-oxidized porphyry copper ores, including the sequence of processes:

- crushing followed by grinding the ore to a characteristic particle size of 0.075 mm;

- flotation concentration of sulfide minerals of copper, molybdenum and zinc in flotation concentrates, with additional flotation release of pyrite concentrate;

- dehydration of flotation concentrates;

- subsequent oxidative roasting of sulphide concentrates with the aim of obtaining sulfuric acid, butt of precious, non-ferrous, rare and rare-earth metals and iron;

- by-pass capture of easily sublimated rhenium from waste gases during firing of sulphide molybdenum concentrate, and germanium during firing of zinc sulphide concentrate;

- accelerated by ultrasound leaching of calcine in an aqueous solution of sulfuric acid;

- washing and dewatering of flotation tailings and cake formed during the leaching of the concentrate and their dry storage followed by the use of the liquid phase in the cycles of flotation concentration and leaching;

- combining the liquid leaching phase of the concentrate with the wash water of the leaching cake;

- isolation of arsenic by sulfatizing solutions after copper cementation, while the ratio of iron ions to arsenic ions exceeding 8: 1 leads to the formation of iron-arsenic complex in the form of artificial scorodite and at the same time intensive binding of arsenic in the form of orpiment;

- release by ultrasonic filtration of the combined liquid phase from solid suspensions and return it to the process;

- electroextraction of copper from leaching solutions of copper cinder with obtaining cathode copper;

- electroextraction of zinc to produce cathode zinc metal.

Most of the porphyry copper ores are complex, and along with copper contain in commercially attractive quantities molybdenum, zinc, lead and other metals. Examples are ores, for example, from the Gaysky deposit (Southern Urals, Russia), the Erdenet deposits (Mongolia), and the Iberian ore belt (Spain, Portugal). A characteristic feature of ores of this type is a high content of metals in pyrite, containing, as a rule, precious metals - gold and silver, as well as a number of non-ferrous, rare and rare-earth metals - copper, zinc, lead, cobalt, titanium, rhenium, etc. .

Classical methods of processing ores of this type provide for crushing, grinding, classifying ore and subsequent flotation to produce sulfide flotation concentrates of copper, zinc, molybdenum, lead. A feature of these schemes is the depression of pyrite, pyrrhotite and arsenopyrite and the direction of these minerals in the flotation tailings. (J. Baatharhuu. "Technology of enrichment of porphyric copper ores based on the study of their genetic and morphological features."., Erdenet, 2006; Karnaukhov, SN "Research and development of technology for processing of copper-molybdenum ore at Erdenet OÜ with the use of selective collectors and an organic depressor in order to increase the extraction of molybdenum "candidate. Diss., Moscow 207, 135 s; Polkin SI, Adamov EV" Technology of enrichment of ores of non-ferrous metals. "M." Nedra "1979 .). As a result, the implementation of classical methods for processing copper ores is accompanied by irretrievable losses of gold, silver, a number of non-ferrous, rare and rare earth metals, as well as iron stored with pyrite in the flotation tailings, polluting oxidation products of surface and ground waters.

At the mining and processing plants, designed according to the above principle, the final product is flotation concentrates of copper and other non-ferrous metals and no further redistribution is provided for, the purpose of which is to obtain more valuable products, such as cathode copper.

Recently, for the processing of ores of this type, technological schemes are applied, including hydrometallurgical methods for extracting metals from oxidized ores and copper sulphide concentrates, differing in methods of opening ore concentrates, extraction of metals from leaching solutions, sequence of technological operations, methods of separation of solid and liquid phases, the organization of flows, the sequence and layout of technological operations (Patents of the Russian Federation No. 2632740, No. 2632742, No. 2659505).

There is a method of extracting copper from copper-containing material, which consists in crushing, grinding the original product, the oxidative leaching of copper with an ammonia solution, removing copper from leaching solutions and subsequent flotation. (US No. 579465, 1998). The disadvantage of this method is its low efficiency and environmental insecurity caused by the use of ammonia.

There is also known a method of extracting copper from sulfide copper ore or concentrate (US No. 6455019, 2002), which includes pressure oxidation, in the presence of hydrochloric acid ions or sulfate ions. The disadvantage of this method is the use of expensive, difficult to operate equipment, the aggressiveness (high corrosivity) of hydrochloric acid, the complexity and the multi-stage process.

There is a method of processing copper-containing mineral products (RU No. 21959589, 2002), which includes crushing, grinding ore, leaching with sulfuric acid, extraction of copper from leaching solutions and flotation. The disadvantage of this method is the high consumption of sulfuric acid, a significant amount of leaching apparatus, obtaining copper-containing marketable intermediate in the form of relatively cheap sulfide concentrate, as well as irretrievable losses of gold, silver, copper, zinc, rare and rare-earth metals and iron with pyrite lost with flotation tailings.

The closest to the claimed method to the technical essence is the processing of sulfide-oxidized copper ores (RU # 23317160), including dry crushing and grinding of ore to a particle size of 0.074 mm, collective flotation of sulfide-oxidized ore with obtaining collective concentrate, subsequent leaching of the collective concentrate with oxygen-containing reagent ( ozone, hydrogen peroxide), the separation of the solid and liquid phases by filtration and the subsequent extraction of copper from the filtrate to obtain cathode copper.

A common significant drawback of all the considered schemes for the processing of copper-containing ores and products is:

- the absence of a technological scheme that includes the operations of hydrometallurgical processing of not only copper products, but also sulfide concentrates of molybdenum, zinc, pyrite, allowing to obtain valuable products in the form of the corresponding metals or their salts and oxides;

- permanent losses of gold, silver, parts of copper, zinc, rare, rare-earth metals with pyrite lost in the flotation tailings;

- use in some cases of such leaching reagents as ozone and hydrogen peroxide, which easily decompose at elevated temperatures, requiring complex special equipment for carrying out the leaching process, which leads to a low coefficient of copper extraction during leaching of sulfide concentrate;

- storage of pyrite in the tailing dump causing irreparable damage to the environment due to the oxidation of pyrite and pollution of the water-air basin with heavy metal ions and sulfate ions.

A new technical result in the implementation of the present invention is achieved by the inclusion in the technological flotation scheme for the processing of copper-containing ores:

- flotation separation of pyrite metal-containing concentrate, along with the resulting target sulphide flotation concentrates;

- selective roasting of sulphide flotation concentrates;

- acceleration of the leaching process by ultrasound;

- intensification of the release by ultrasonic filtration of solutions from solid suspensions, before returning the liquid phase to the process;

- dehydration of production wastes and dry storage with the organization of the circulating use of the liquid phase.

The obtained sulfide pyrite concentrates, as well as flotation concentrates of copper, molybdenum and zinc, are selectively calcined in fluidized bed furnaces with the aim of obtaining sulfuric acid, which is further used for accelerated ultrasound (SU # 1131553, 1983), sulfuric acid leaching of copper, molybdenum zinc and pyrite cinder with the aim of obtaining soluble metal sulfates, from solutions of which, after separation of the solid and liquid phases by ultrasonic filtration (Akopian VB, Ershov Y.A. The basics of the interaction of ultrasound with biol Moscow, YURAYT Publishing House, 2016, 223 C.), is extracted by liquid extraction with an organic extractant, for example, CYANEX 272, the active component of which is di (2,4,4-trimethylpentyl) phosphinic acid, copper and zinc with the subsequent production of copper cathode and zinc by known methods. When firing sulphide molybdenum concentrate flue gases catch easily sublimated rhenium, and during firing sulphide zinc concentrate germanium.

The implementation of the proposed technology allows obtaining new types of valuable products: molybdenum trioxide, ammonium paramolybdate, cathode copper and zinc, rhenium in the form of ammonium perrhenate, germanium oxide, gold, silver, cobalt and titanium, as well as other noble, nonferrous, rare and rare earth metals, arsenic compounds, pigment-grade iron oxides (Patents of the Russian Federation No. 2655 336, No. 2656 047, No. 267489), as well as high-purity iron suitable for the production of high-alloy special steels and steels for the electrical industry with specified magnesium oelektricheskimi properties.

This technical result, which ensures the transfer of the existing technology of mining and processing enterprises to the technological level of a higher level, is achieved as follows.

The original copper-containing ore or copper-containing product in the form of slag or sludge is subjected to crushing, grinding and classification, ensuring optimal grinding fineness and guaranteeing the maximum selective disclosure of useful minerals, their release from adhesions with the host rock and associated minerals. Thus prepared ore, converted into pulp, is subjected to flotation with the successive production of flotation concentrates of copper, zinc, and molybdenum, and an additional operation for the production of flotation pyrite concentrates is introduced into the flotation process cycle. The flotation tails are thickened with the addition of flocculating agents and filtered on ultrasonic filters, the filtrate is used as a circulating liquid phase, and the filter cakes are dry deposited into spent mine workings. The resulting sulphide concentrates plunge oxidative roasting on selective lines, emit molybdenum sulphide concentrate from roasting gases, emit rhenium by a known method, emit zinc sulfide concentrate from roasting gases, and emit arsenic from a pyritin concentrate roasting gases. After the release of rhenium, germanium and arsenic, the firing gases enter the workshop for the production of sulfuric acid. A characteristic feature of sulphide concentrates roasting is the release of a large amount of thermal energy after initiating a thermal oxidation reaction, which in practice leads to minimization of energy consumption in production.

Theoretically, when burning one ton of pyrite cinder containing 53% sulfur, 1.6 tons of sulfuric acid can be obtained, and in practice 1.2-1.4 tons of sulfuric acid are obtained.

The mechanism of roasting and thermal oxidation of pyrite concentrate has a multistage character, but in its final form, it can be reflected by the total chemical reaction of thermal oxidation, for example, pyrite concentrate to produce sulfuric acid and calcine containing gold, silver, oxides of copper, zinc, cobalt, titanium, rare and rare-earth products oxidation:

Similar reactions underlie the thermal oxidation of sulphide concentrates of molybdenum, zinc and copper sulphide concentrates.

The resulting roasting oxides of copper, zinc and iron are leached on separate lines, while the sulphate of metals passes into the solution according to the reactions:

At the same time, for sulfuric acid leaching by reactions 2, 3, 4, sulfuric acid is used, which is obtained in the process of roasting sulfide flotation concentrates within the same technological scheme by reaction (1).

Pyrite cinder, obtained as a result of roasting of flotation pyrite concentrate, contains, depending on the conditions of genesis and mineral formation, from 1.0 to 10.0 g / t gold, up to 50 g / t silver, 200-500 g / t cobalt, 0, 4-1.2% copper, 2.1-3.5% zinc, 0.1-0.21% titanium.

Sulfur-containing gases formed during thermohydrolysis of ferrous sulfate according to reaction (5) are fed to the scheme for producing sulfuric acid during roasting of pyrite concentrate.

After purification from metals and bringing the concentration of sulfuric acid to values exceeding 150 g / dm ³ , the liquid phase is sent to the process head for ultrasonic accelerated sulfuric acid leaching of calcine, and the mineral residue containing gold, silver, calcium sulfate, iron residues in the form of magnetite , barium sulfate and quartz come to the operation of extracting precious metals in the form of Dore alloy.

The implementation of the invention is illustrated by the following examples, not wearing, however, restrictive.

Example 1. Copper sulphide ore from the Erdenet deposit, containing 0.47% of copper and 4.2% of pyrite, is enriched to produce copper and molybdenum concentrates by the flotation method, supplemented by a scheme of flotation separation of pyrite. The composition obtained in the flotation cycle concentrates are shown in Table 1.

The resulting flotation concentrates are roasted in fluidized bed furnaces to produce sulfuric acid on three parallel roasting lines, separate for each type of concentrate, while the sulfur-containing gases, after cleaning and trapping rhenium, enter the sulfuric acid production plant. Additionally, rhenium is extracted from sulfuric acid in the molybdenum concentrate burning line by an organic extractant using a solvent extraction method, followed by concentration of rhenium by reextracting the saturated organic phase, and the raffinate is returned to the washing step.

Burned, thus, the cinder comes to the stage of hydrometallurgical processing, which consists in the sulfuric acid leaching of the target components with own-produced sulfuric acid with a concentration of from 50 to 350 g / dm ³ , at a temperature of 50-90 ° C, the leaching process duration is 1.5-8, 0 hours and a solid-to-liquid ratio of 1: 3-6, Pulp, after sulfuric acid leaching, are filtered using frame press filters, the cakes are washed, the washing waters are returned to the sulfuric acid leaching stage, and sulfuric acid astvory operation directed to the selective extraction of the desired components by known carburizing techniques and sulphidation followed by obtaining commodity iron compounds when leaching pyrite cinder sulfuric acid solutions, followed elektoroosazhdeniem copper enriched at the expense of iron extraction, the copper-containing solution to yield cathode copper. The extractant, after adjusting the concentration of sulfuric acid to values in excess of 150 g / dm ³ , is repeatedly and repeatedly used at the leaching stage of the copper cinder.

Leaching of pyrite cinders with sulfuric acid solutions with a concentration of 150-250 g / dm ³ at a temperature of 60-90 ° C and a solid-to-liquid ratio of 1: 3-6 and a process time of up to 6 hours takes place in accordance with the equations of chemical reactions (2, 3 , four). After the stage of the sulfuric acid leaching of pyrite cinder, the pulp was separated by filtration, the filtration cakes were diluted with sulfuric acid with a concentration of 150-250 g / dm ³ to a T: W ratio of 1: 3-6 and leached again at 60-90 ° С for 3 6 hours, because they still contained a fairly high amount of valuable components

Complete leaching of iron from cinders is possible in one stage, however, this requires a too high T: W ratio, large volumes of extraction equipment, as well as extractant, and the resulting substantial costs of extracting iron compounds. Leaching of calcine in two stages is very effective, because in complex salt systems in the presence of sulphate of copper, zinc, cobalt, titanium, and often manganese, saturation of the solution with iron sulphate occurs at a concentration of 110-150 g / dm ³ , repeated leaching - the second stage - ensures complete, up to 95-98% extract iron into solution. Sulfuric acid solutions after the first and second leaching stage are fed to the purification of copper, zinc, cobalt and rare earth metals with further separation of ferrous sulfate by vacuum crystallization, filtration and washing on the filter from impurities. The resulting ferrous sulfate was dissolved in water and sent for hydrolytic precipitation operations with alkaline reagent in the form of ammonia or soda to produce iron oxide hydrate, which is dried by removing hydrated and pore moisture at a temperature of 250-400 ° C for 3-6 hours, after which thermo-oxidation is performed to obtain iron trioxide at a temperature of 650-700 ° C for 3-6 hours.

Keki, after the sulfuric acid leaching of pyrite calcine, enters the leaching of gold and silver. This operation, in contrast to traditional cyanidation, is carried out in an acidic medium with the use of trivalent iron and pyrolusite compounds as an oxidizing agent, and chlorine ion as an gold complexing agent. At the same time, a gold-chloride complex of the general formula is formed in the solution. After the first and second leaching stages, the sulphate solutions are fed to copper, zinc, cobalt and rare-earth metals, with further separation of the blue vitriol by filtration and washing the impurities on the filter with [AuCl ₄ ] ^- . The use of a chlorine-containing complexing agent in an acidic environment is quite economically and technologically justified, since in the solid phase there remain mostly inert minerals that do not react with chlorine. At the same time, the indisputable advantages of the gold leaching chloride system are as follows:

- high oxidative activity and more complete extraction of gold due to the accelerated (up to 13 times) dissolution of gold,

- availability and lower cost of reagents,

- low compared with cyanides, the toxicity of the reagents used,

- production of ferric iron, as an oxidizing agent, directly during pyrite leaching.

In the cakes, after the sulfate leaching of pyrite cinders, the yield of which is 13-20% of the operation, the relative gold content increases to 50-65 g / t and silver to 200 g / t. Cathode copper extracted by electrodeposition is 84.9%, and molybdenum extracted in the form of trioxide is 28.9%. The extraction of iron in the form of a pigment-quality trioxide is 98.6%, the extraction of gold by the cyanide-free method to Dore is 97.3%, and that of silver is 74.5%. In addition, 96.38% of copper contained in them, 91.3% of zinc, and 95.7% of cobalt are extracted from pyrite butts.

Example 2

Prepared for leaching, in accordance with Example 1, butts are subjected to sulfuric acid leaching with sulfuric acid with a concentration of from 50 to 350 g / dm ³ , at a temperature of 50-90 ° C, in a solid-to-liquid ratio equal to 1: 6, in an ultrasonic field of wide-band hydrostatic radiator with acoustic energy density of 0.1-1.0 W / cm ³ for 0.3-2.0 hours, which allows to reduce the process time by 4-5 times.

After sulfuric acid leaching, the pulp is filtered using ultrasonic filters, which allows the filtration rate to be doubled, with the same filter sizes, and to maintain the flow rate during the entire filtration process, which is caused by a decrease in diffusion limitations in the ultrasonic field and continuous release of the filter element from the choker his sediment It should be noted that the use of ultrasonic filtration practically does not affect the total time of implementation of the claimed method, but significantly simplifies the maintenance of the technological process.

Example 3

Copper ores of the Gaysky deposit contain, on average, copper 1.3%, zinc 0.52%, gold 1.1 g / t, silver 10.1 g / t. To implement the claimed method, the ore was processed by the flotation scheme for obtaining copper and zinc sulfide concentrates, and in the case of roasting and hydrometallurgy, copper sulfide concentrate was used, containing 17.66% copper, 33.5% iron, 0.36% arsenic, 39, 3% sulfur, 4.8 g / t gold, 83 g / t silver, and zinc sulphide concentrate, with a zinc content of 41.2%, up to 3.8% copper and 0.6% arsenic. The existing flotation scheme was supplemented by a flotation stage for the extraction of pyrite concentrate containing 42.1% sulfur, 36.9% iron, 3.2 g / t gold, 29.1 g / t silver.

Copper, zinc, and pyrite flotation sulfide concentrates were roasted, and copper, zinc, and pyrite cinders were leached by leaching with sulfuric acid solutions of various concentrations according to the scheme shown in Example 1. At the same time, 90.6% of copper was recovered to electrolytically separated copper, through extraction of zinc in electrolytically isolated zinc metal 93.6%, extraction of iron from pyrite calcine to pigment quality trioxide 97.8%, additional, in terms of cinder, extraction of copper 91.2%, additional echenie 96.3% zinc, and gold and silver extraction method in beztsianidnym dore was 98.8% and 76.3% respectively.

Our additional studies on the variation of various physical parameters of the process when searching for optimal modes showed that when each of these parameters changes, both upwards and downwards (with the other parameters remaining constant), the efficiency of the processes decreased. Studies have shown that the parameters of the claimed method, as described in the application for invention, are optimal and the invention can be implemented using the means and methods described in the application, and the combination of distinctive features of the described method ensures the achievement of this result.

For the inventive method, as described, there are no obstacles to its implementation in practice using modern technical means.

Claims (1)

The method of complex processing of sulfide-oxidized porphyry copper ores, including crushing and subsequent grinding of ore to a particle size of not more than 0.075 mm, flotation and concentration of copper, molybdenum and zinc sulfide minerals, characterized in that they additionally carry out flotation separation of pyrite concentrate followed by oxidative calcination of sulfide concentrates, obtaining sulfuric acid from gases formed during roasting, as well as cinders of non-ferrous metals and iron, followed by leaching of cinders in an aqueous solution sulfuric acid with a concentration of 110-250 g / dm ³ , when the content of the solid phase is 10-50%, at a temperature of 20-90 ° C, the concentration of ferric ions to 50-250 g / dm ³ during 0.3-2.0 hours in the ultrasonic field hydroacoustic transducer with acoustic energy density of 0.1-1.0 W / cm ³ , then washing and dewatering the concentrate leaching cake are combined, the liquid leaching of the concentrate is combined with the washing leaching cake, and the combined liquid phase is freed from ultrasonic solids filtering and return liquid phase in the process, copper extraction is carried out from leaching solutions of the calcine to obtain 96.38% of electrolytic copper contained in it, 91.3% of zinc, extraction of zinc to obtain electrolytic metallic zinc, 98.6% of iron in the form of trioxide and extraction of gold 97.3% and 74.5% silver without the cyanide method in Dore alloy.