Method of flotation of zinc-comprising sulfide ores of non-ferrous metals

Abstract

FIELD: mineral concentration.SUBSTANCE: invention relates to the field of mineral concentration by the froth flotation method, in particular to the concentration of sulfide zinc-comprising ores of non-ferrous metals, and can be used for the concentration of sulfide polymetallic, copper-zinc and lead-zinc ores. The method for flotation of sulfide zinc-comprising ores of non-ferrous metals includes grinding, agitation, inter-cycle flotation of two or more metals in a lime medium with a collector, frother and depressor, regrinding of the zinc-comprising product, flotation separation of zinc sulfides into a crude zinc concentrate using a copper-comprising activator of zinc sulfides, a reagent-collector, frother and depressor of silica-comprising rock minerals, staged re-cleaning followed by flotation in a lime medium of the crude zinc concentrate to obtain purified zinc concentrate and separation of iron sulfides and silica-comprising rock minerals into waste tailings. As a depressant reagent for silica-comprising rock minerals in the production of purified zinc concentrate, a depressant is used, which is a mixture comprising copolymers of acrylic and carboxylic acids, carboxylic acid anhydrides, polyhydric alcohols, organosilicon compound, amines, taken respectively in the following weight ratio, wt.%: copolymers of acrylic and carboxylic acids 5-30; carboxylic acid anhydrides 5-30; polyhydric alcohols 10-50; organosilicon compound 10-50; amines 1-5. The depressant and copper-comprising activator of zinc sulfides are in a weight ratio of (0.1-5):1, respectively.EFFECT: production of high-quality purified zinc concentrate while simultaneously increasing the completeness of zinc extraction into the purified zinc concentrate.3 cl, 2 dwg, 1 tbl, 3 ex

Description

[0001] The invention relates to the field of mineral enrichment by the froth flotation method, in particular to the enrichment of sulfide zinc-containing ores of non-ferrous metals, and can be used for the enrichment of sulfide polymetallic, copper-zinc and lead-zinc ores.

[0002] In zinc-bearing sulfide ores, the valuable components can be represented by various minerals: copper – by primary (chalcopyrite, cubanite) and secondary sulfides (chalcocite, covellite, bornite); lead – by galena; zinc – by various varieties of sphalerite (sphalerite, marmatite, brunkite, proustite, etc.); iron sulfides – by pyrite, marcasite, and pyrrhotite. The ores also contain valuable by-products: precious metals (gold, silver) and rare metals (cadmium, indium, gallium).

[0003] Sphalerite is the main industrial source of zinc and, depending on the deposit type, is characterized by various impurities, the most common of which is iron. The presence of iron in the sphalerite lattice significantly influences its physical properties and the technological processes for extracting this mineral.

[0004] The greatest difficulties for flotation separation of zinc sulfides (sphalerite), pyrite, and silica-bearing rock are posed by corroded and colloform varieties of pyrite; brittle, easily sludged, and flotation-active silicates / aluminosilicates. However, in the absence of "hard" modifiers (sphalerite activators, pyrite depressants, and flotation-active silica-bearing rock), these minerals acquire similar flotation properties.

[0005] As a rule, technologies for processing zinc-containing ores do not have direct analogues and are developed for each specific type of raw material and deposit (Abramov A.A. Processing, enrichment and complex use of solid minerals: In 3 volumes. - M .: Publishing house of Moscow State Mining University, 2004. - Vol. II. Technology of mineral enrichment. - 510 p.).

[0006] Involvement of zinc-containing sulphide ores with a high content of waste rock in the processing leads to a decrease in the quality of the resulting zinc concentrates and their contamination with waste rock.

[0007] In this regard, it is important to search for depressant reagents that provide targeted selective suppression of flotation-active rock-forming mineralization, including silica-containing minerals of gangue and that allow regulating the flotation abilities of minerals (Lavrinenko A.A., Makarov D.V., Shrader E.A., Sarkisova L.M. Increasing the selectivity of the separation of sulfides and flotation-active silicates during the enrichment of low-sulfide platinum metal ore / / Scientific foundations and practice of processing ores and technogenic raw materials. - 2019. - P. 112-24; Kuznetsova I.N., Lavrinenko A.A., Shrader E.A., Sarkisova L.M. Reducing the extraction of flotation-active silicates into collective concentrate during the flotation of low-sulfide platinum metal ore / / Mining information and analytical bulletin. - 2019. - No. 5. - P. 200-208).

[0008] Silica-containing gangue minerals are the main impurity components that reduce the quality of zinc concentrate. They dilute the concentrate and cause difficulties during its subsequent metallurgical processing. In this regard, the most important quality indicator of flotation zinc concentrate, in addition to the content of the target useful component (zinc) and impurity metals (copper, iron), is the silica content (SiO2). For example, for zinc concentrate grade KTs-3 (50% Zn), the mass fraction of silicon dioxide is regulated at "no more than 4.0%" (Zinc concentrates / / GOST R 54922-2012. Technical conditions / National standard of the Russian Federation. - M .: Standartinform. - 2014. - P. 4).

[0009] Currently, the problem of reducing silica-containing impurities in zinc concentrate during the flotation of polymetallic, copper-zinc, and lead-zinc ores has become particularly acute due to the increase in zinc production and the simultaneous increasing complexity of the structural and textural characteristics and material composition of the processed ores. Flotation of sphalerite from copper-lead, copper, or lead cycle tailings presents inherent difficulties due to its low content in this middling product compared to silica-containing gangue and pyrite minerals, as well as the nature of sphalerite's dissemination with sulfide and nonmetallic minerals.

[0010] The separation of sphalerite from pyrite and gangue in all variants of the process flow charts is carried out using the same reagent regime - in a highly alkaline environment (pH = 10-12) using lime, copper sulfate and a collector (sometimes cyanide), while the extraction of pyrite from zinc flotation tailings is possible only if the influence of lime is eliminated.

[0011] Maximum selectivity in flotation separation of minerals with similar properties is achieved by using depressant reagents.

[0012] Of all organic depressants, the most widely used in industry are reagents belonging to the groups of non-ionogenic and ionogenic anionic depressants. For example, soluble starch and dextrin, belonging to the group of non-ionogenic depressants, are used for the depression of flotation-active silicates during the flotation of sulfide ores. Selective suppressors of flotation-active silicates, such as talc, sericite, chlorite, etc., are also widely used in the flotation of sulfide ores: carboxymethyl cellulose (CMC), sulfate and cellulose sulfonate, belonging to the group of ionogenic anionic depressants (Abramov A.A. Collected Works: Vol. 8: Flotation. Sulfide Minerals: Study Guide. - Moscow: Publishing House "Gornaya Kniga", 2013. - 704 p.).

[0013] A known method for preventing flotation of non-metallic silica-containing minerals activated by heavy metal ions is using depressants based on polysaccharides such as CMC and its derivatives, modified guar gums, etc. (Patent RU No. 2 588 098 C1, cl. B03D 1 / 02; B03D 1 / 004; B03D 103 / 02. - Published on 27.06.2016 - Bulletin No. 18). However, in the presence of a high content of calcium ions in the zinc flotation feed, complete suppression of silica-containing minerals does not occur when using the said depressants.

[0014] A known method for flotation enrichment of polymetallic copper-lead and lead-zinc sulfide ores involves the addition of a known reagent composition to the mill to suppress sphalerite and the additional addition of dimethyldithiocarbamate (DMDC). The ground pulp is conditioned. Then, collective copper-lead flotation is carried out in a weakly alkaline medium, separating copper and lead minerals into a collective concentrate. After sphalerite activation by known methods, the pulp is conditioned with the Beraflot collector and zinc minerals are selectively floated into zinc concentrate (Patent RU No. 2 379 116 C1, class B03D 1 / 00; B03D 1 / 02, Published 20.01.2010. Bulletin No. 2). The disadvantage of this method is the low efficiency of the reagent mode implemented in the zinc flotation cycle, and a high degree of dilution of the resulting zinc concentrate with silica-containing minerals of gangue.

[0015] In addition to the above depressants, the following are also used as depressants to suppress the flotation activity of silica-containing rock during flotation enrichment of non-ferrous metal ores: sodium fluorosilicate, pyrophosphate, tripolyphosphate, hexametaphosphate, lignin sulfate, carbosulfite and carbothionosulfate, trisodium phosphate, lignosulfonates, etc. (Eigeles M.A. Reagents-regulators in the flotation process. - Moscow: Nedra, - 1977. - 216 p.; Abramov A.A. Processing, enrichment and complex use of solid minerals: Textbook for universities. In 3 volumes. - Moscow: Publishing House of Moscow State Mining University, 2004. - Vol. II. Technology of mineral enrichment. - 510 p.).

[0016] However, as practice shows, the use of these depressants in the flotation of zinc-containing sulfide ores containing flotation-active silicates, their action is not effective enough.

[0017] In the invention (Patent RU No. 2 209687 C2, cl. B03D 1 / 001; 1 / 016 / / B03D; 101:06; 103:02; C08B11 / 12. - Published on 10.08.2003.) during the flotation of sulfide ores of non-ferrous metals, a chemical compound based on cellulose and starch derivatives is used as a depressant reagent for silica-containing minerals of gangue. These compounds have the property of dissolving in water to form colloidal solutions and suppressing the flotation of gangue. A disadvantage of this known method is the low efficiency of this depressant with an increased quartz content in the original ore and in the presence of a high content of calcium ions in the zinc flotation feed.

[0018] A known method for flotation of zinc sulfide minerals, in which the initial flotation feed is the tailings of the copper-lead flotation cycle formed during the flotation enrichment of sulfide polymetallic ores. The enrichment circuit additionally includes a zinc-pyrite flotation operation, preceded by an attrition operation in the presence of activated carbon. Flotation of zinc sulfide minerals is carried out at a temperature of at least 30 °C. The technical result of the known method is to improve the quality of zinc concentrate mainly due to the attrition operation (Patent RU No. 2 588 098 C1, cl. B03D 1 / 02; B03D 1 / 004; B03D 103 / 02. - Published on 27.06.2016 - Bulletin No. 18). A significant disadvantage of the known method is the low efficiency of the reagent regime implemented in the zinc flotation cycle.The presence of a significant amount of low-strength, highly brittle rock minerals in the ore can cause them to become over-sludged during the grinding process, which will ultimately lead to a deterioration in the flotation and thickening process (due to the presence of fine suspension in the pulp) and contamination of the concentrates with rock minerals.

[0019] The closest to the proposed method in terms of the combination of features and the achieved result is the method of flotation enrichment of polymetallic ores containing sulfide minerals, carried out according to the selective-collective-selective flotation scheme, including: the 1st stage of ore grinding to 70% of the size class of -74 μm with flotation of the copper "head"; the 2nd main copper-lead flotation after regrinding the middling product to 85% of the size class of -74 μm; the 3rd main and control copper-lead flotation after regrinding to 95% of the size class of -74 μm; attrition of concentrates of the main copper-lead flotation and their 3-stage re-cleaning with subsequent selection of copper-lead concentrate after washing and thickening into copper (foam) and chamber (lead) products. The copper cycle tailings, after thickening and washing, are sent to the lead flotation cycle, which involves cleaning the lead concentrate.Lead cycle tailings and copper-lead cycle middlings are fed to the middling copper-lead cycle, the tailings of which are fed to zinc-pyrite flotation, and the concentrate to the primary copper-lead cleaning. Zinc concentrate is obtained from the copper-lead flotation cycle tailings, which is fed to cleaning. The copper-lead cleaning and zinc cycle utilize the following reagents: lime, sodium sulfide, zinc sulfate, collector (Aero 9863) or (Aerophine 3418A), frother (Flotanol C-7), collector (xanthate), and depressant (NaCN). CMC depressant is used to suppress silica-bearing rock flotation in the zinc cycle. This method produces zinc concentrate of the KTs-3 grade (Poperechnikova O.Yu., Nazarov Yu.P., Kutlin B.A. et al. Processing of polymetallic ores of the Korbalikhinsky deposit / Scientific foundations and practice of processing ores and technogenic raw materials: materials of the XXVI National Scientific and Technical Conference, May 26-27, 2021., held within the framework of the XIX Ural Mining Decade on May 19-29, 2021 - Ekaterinburg: Fort Dialog-Iset Publishing House, 2021. - Pp. 28-34) - PROTOTYPE.

[0020] A significant disadvantage of the prototype method is the low quality of the final zinc concentrate in terms of silicon dioxide content - up to 4% SiO2 (with the existing requirement - no more than 1.5% SiO2) and the content of the regulated amount of impurities - (Cu + Pb + SiO2) no more than 4.5%. The reagent flotation mode used in the prototype method in combination with the attrition technique does not provide acceptable results for zinc-containing ores, has a high level of zinc loss with flotation tailings, which is due to the low selectivity of the attrition operation and is accompanied by a significant increase in the loss of valuable components, as well as a high level of capital costs and energy consumption during the attrition operation, which complicates the separation of zinc sulfides and silica-containing rock.

[0021] The problem solved by the invention is to obtain high-quality purified zinc concentrate while simultaneously increasing the completeness of zinc extraction into purified zinc concentrate by optimizing the reagent flotation mode.

[0022] The technical result of using the invention is an increase in the extraction of zinc into purified zinc concentrate with a minimum silicon dioxide content (no more than 1.5%) and a content of the sum of impurities (Cu+Pb+SiO2) of no more than 4.5% by optimizing the reagent flotation mode through the use of an effective composite reagent-depressant that selectively acts in relation to silica-containing minerals of the rock.

[0023] To achieve the claimed technical result, a method is proposed for flotation of sulfide zinc-containing ores of non-ferrous metals, including grinding, agitation, inter-cycle flotation of two or more metals in a lime medium with a collector, frother and depressor, regrinding of the zinc-containing product, flotation separation of zinc sulfides into a rough zinc concentrate using a copper-containing activator of zinc sulfides, a reagent-collector, frother and depressor of silica-containing rock minerals, staged re-cleaning followed by flotation in a lime medium of the rough zinc concentrate to obtain purified zinc concentrate and the separation of iron sulfides and silica-containing rock minerals into tailings, characterized in that the depressor "RD 1033" is used as a reagent-depressor for silica-containing rock minerals in obtaining purified zinc concentrate, which is a mixture,which includes copolymers of acrylic and carboxylic acids, carboxylic acid anhydrides, polyhydric alcohols, organosilicon compound, amines and water, taken respectively in a weight ratio, wt.%:,

[0024] copolymers of acrylic and carboxylic acids 5-30;

[0025] Carboxylic acid anhydrides 5-30;

[0026] polyhydric alcohols 10-50;

[0027] polysilicon organosilicon compound 10-50;

[0028] amines 1-5;

[0029] water 0-4,

[0030] in this case, the depressant “RD 1033” and the copper-containing zinc sulfide activator are in a weight ratio of (0.1-5):1, respectively.

[0031] The proposed mechanism of action of reagent "RD 1033" as a depressant for silica-containing gangue minerals (quartz, muscovite, clinochlore, feldspar, etc.) is the formation of a hexagonal complex with a silicon ion at its center. The self-formation of the so-called supramolecular structure with silica-containing gangue minerals is based on the interaction of van der Waals forces, π-π donor-acceptor interactions, and hydrogen bonds. Partially unused hydrophilic groups, primarily hydroxyl (-OH), remain in the outer shell of the resulting molecular hexagonal complex. These groups prevent the silica-containing complex from adhering to air bubbles, retaining the gangue mineral particles in the chamber flotation product.

[0032] It has been experimentally established that achieving the stated technical result and ensuring the highest quality of purified zinc concentrate with a content of ≥ 50% Zn and ≤ 1.5% SiO2 while simultaneously increasing zinc recovery into purified zinc concentrate in the zinc flotation cycle is only possible with a combination of the RD 1033 depressant reagent and a copper-containing zinc sulfide activator. This was not previously evident from the practice of flotation methods for zinc-containing sulfide ores of non-ferrous metals and was an unexpected result, confirming the inventive step of the present invention.

[0033] The following can be used as a copper-containing activator of zinc sulfides: copper sulfate (copper sulfate - CuSO4×5H2O or nanosized copper oxyhydroxide CuO×nH2O, or nanosized copper minerals (covellite - CuS, bornite - Cu5FeS4.

[0034] The consumption of the RD 1033 depressant and the copper-containing zinc sulfide activator should be interrelated and maintained at an optimal mass ratio in the range of (0.1-5):1. When this ratio decreases to less than 0.1:1 (extremely low consumption of the RD 1033 depressant), the highly dispersed minerals of the flotation-active silicates of the rock undergo an intensive transition to a froth layer during flotation, with a sharp increase in the silicon dioxide and iron content of the purified zinc concentrate and a simultaneous decrease in its zinc quality (≤ 50% Zn). In this case, the zinc and silicon dioxide content in the purified zinc concentrate approaches those of the prototype method in these indicators. When the specified ratio increases above 5:1 (an extremely high consumption of the RD 1033 depressant), some of the large sphalerite grains and intergrowths of zinc sulfides with silica-containing minerals of the host rock are irretrievably lost with the tailings of the zinc flotation cycle.As a result, zinc recovery in purified zinc concentrate is significantly reduced, while silicon dioxide content increases. Flotation performance is reduced to levels comparable to those of the prototype method (see Table 1, Example 3, Experiments 5 and 6).

[0035] Information on the use of the distinctive features of the present invention, which provide the claimed technical result during the flotation of sulfide zinc-containing ores of non-ferrous metals, was not revealed during the study of scientific, technical and patent literature, which indicates the novelty of the present invention.

[0036] The method is carried out as follows.

[0037] Sulfide zinc-bearing non-ferrous metal ore is subjected to ore preparation, wet staged grinding of the material to a size of 70-75% of the -71 µm class in a lime environment, classification and agitation with reagents - collectors, frothers and modifiers, followed by inter-cycle flotation of two or more metals with the separation of their rough bulk concentrate, which is subjected to staged re-cleaning and subsequent selection to obtain one or more finished selective non-ferrous metal concentrates. The zinc-containing product of the inter-cycle flotation is re-ground to a size of 95-98% of the -71 µm class. This product concentrates the bulk of the zinc sulfides (sphalerite), iron (pyrite, pyrrhotite, marcasite) and gangue minerals contained in the ore. This product is the initial feed for the zinc flotation cycle. Intercycle flotation is carried out using a zinc sulfide depressant and a silica-containing gangue mineral depressant.Known depressants and their combinations are used as depressants for zinc sulfides (sphalerite), such as a combination of sodium sulfide (Na2S) and zinc sulfate (ZnSO4) in a 1:2 ratio, or zinc sulfate in combination with sodium sulfite (Na2SO3), or sodium pyrosulfite (Na2S2O5) at pH 8.2-8.5, created by lime and sodium cyanide (NaCN). The "RD 1033" depressant claimed in this invention is used as a depressant for silica-containing gangue minerals in the proposed method. Known depressants, such as sodium cyanide, ferrous sulfate, or sodium thiosulfate, as well as combinations thereof, are used during selection of pre-purified bulk concentrate to improve the quality of selective concentrates.The tailings of the collective flotation cycle, in which the bulk of zinc sulphides (sphalerite), iron (pyrite, pyrrhotite, marcasite) and gangue minerals contained in the ore are concentrated, are the initial feed for the zinc flotation cycle.

[0038] The key operation of the zinc flotation cycle is primary zinc-pyrite flotation, which serves to separate the bulk of silica-containing gangue into tailings and concentrate zinc-bearing minerals. Prior to this operation, the feed is agitated using a known collecting reagent (e.g., xanthate, aeroflot, Aerophine 3418A, thionocarbamate, etc., and combinations thereof) and a known frother (e.g., T-92, MIBK, or Flotanol C-7). Lime, a copper-containing zinc sulfide activator, and RD 1033, a depressant for silica-containing gangue minerals, are also added to this operation to depress iron sulfides. The zinc-pyrite flotation concentrate is fed with reagents (lime, collector, copper-containing zinc sulfide activator and RD 1033 depressant) for agitation combined with steaming at 30-35 ºС.After agitation, the prepared concentrate is sent to the main zinc flotation, during which sphalerite is extracted into rough zinc concentrate, and pyrite and residual gangue minerals are extracted into pyrite-containing tailings. The resulting rough zinc concentrate is sent for agitation, which is carried out simultaneously with steaming at 30-35°C with the addition of lime and the RD 1033 depressant. After agitation, the concentrate undergoes staged re-cleaning with the addition of lime, a collector, and the RD 1033 depressant. Tailings from the main zinc-pyrite flotation and the main zinc flotation are sent to separate scavenger flotation circuits. Both scavenger flotations are carried out using the RD 1033 collector and depressant. Tailings from both scavenger flotation circuits (main zinc-pyrite and main zinc) are waste tailings. Concentrates from both scavenger flotations are returned to the main zinc-pyrite flotation "head." The concentrate from the third refining is a finished (purified) zinc concentrate.

[0039] Figures 1 and 2 show the process flow diagram of the proposed method, which can be used for flotation enrichment of pyrite polymetallic ore of complex chemical and mineral composition, containing copper, lead, zinc, pyrite and silica-containing host rock. The target concentrates of the proposed method in this case are total copper concentrate, lead concentrate and purified zinc concentrate of the KTs-2 grade, containing at least 50% Zn; ≤ 1.5% SiO2; the sum of impurities Cu + Pb + SiO2 ≤ 4.5%.

[0040] The proposed method is illustrated by specific examples combining several conducted experiments. The results obtained are presented in Table 1.

[0041] The experiments were conducted on a sample of industrial sulfide polymetallic ore from the Korbalikhinskoye deposit, which was processed at the Rubtsovsk Concentrator (RCP) of JSC Siberia-Polymetals. The flotation products were subjected to volumetric and weight measurements, sampled, and analyzed. The material balance of the concentration process was calculated based on the analysis and measurement results.

[0042] The efficiency of flotation modes in each experiment was assessed based on the quality of the obtained selective concentrates (copper, lead) and, above all, the qualitative and quantitative characteristics of the finished (purified) zinc concentrate - based on the content of zinc, silica and the regulated amount of impurities (Cu+Pb+SiO2), as well as the level of through extraction of copper, lead and zinc into the same selective concentrates.

[0043] Example 1 (Table 1, experiment 1) – implementation of the prototype method.

[0044] The prototype method for enriching pyrite-polymetallic ore from the Korbalikhinskoye deposit proposes a selective-collective-selective flotation scheme, including a copper "head" operation, the tailings of which are fed into copper-lead flotation. Taking into account the specific chemical, mineralogical, structural, and textural characteristics of the ore, this scheme ensures the most complete extraction of copper, lead, and zinc minerals into selective concentrates of the same name.

[0045] The original ore sample was ground in a limestone medium to a 70% content of the -74 µm size class. The pulp of the ground material, after classification and agitation with collecting reagents (Aero 9863 and Aerophine 3418A) and a frother (Flotanol C-7), was preliminarily sent to copper head flotation and then to the first inter-cycle primary copper-lead flotation. Uneven mineral dissemination dictated the staged extraction of copper and lead minerals by fine grinding of the ore after three grinding stages. After regrinding the chamber product of the 1st inter-cycle primary copper-lead flotation to 85% of the size class –74 µm, the pulp was agitated with reagents: xanthate collector, foaming agent (Flotanol C-7), depressant (NaCN) and the 2nd inter-cycle primary copper-lead flotation was carried out.The chamber product from the second rough copper-lead flotation, after regrinding to a 98% fineness of –74 µm, was agitated with the same reagents as in the first rough copper-lead flotation (xanthate, Flotanol C-7, NaCN), and then subjected to the third rough and control copper-lead flotation. The concentrates from the second and third rough copper-lead flotations were combined and subjected to attrition. After attrition, the combined concentrate was sent to the first copper-lead concentrate cleaning circuit, and the concentrate from the first intercycle rough copper-lead flotation was sent to the second cleaning circuit, which was carried out using a NaCN depressant. The copper-lead concentrate from the second cleaning was sent to the desorption of collectors, carried out by the attrition method, then it was sent to washing and thickening, and then to the copper-lead concentrate selection cycle.After washing and thickening, the bulk copper-lead concentrate was separated by flotation into selective copper (froth product) and chamber (lead) concentrate using a NaCN depressant. Copper cycle tailings, after thickening and washing, were sent to the lead flotation circuit, while lead cycle tailings and copper-lead cycle middlings were fed to the middling copper-lead circuit, the concentrate from which was returned to the first copper-lead refining unit.

[0046] Tailings from the copper-lead flotation circuit were the feedstock for the zinc-pyrite flotation circuit.

[0047] Tailings from the copper-lead flotation circuit were first sent to an attrition stage, which was carried out in the presence of activated carbon, lime, and copper sulfate. The prepared pulp was agitated with a selective collector of zinc sulfide minerals (Aerophine 3418A), a frother (Flotanol C-7), and a gangue depressant (CMC), after which the reagent-treated pulp was sent to the main zinc-pyrite flotation. The froth product of the main zinc-pyrite flotation was sent to an attrition stage, carried out in the presence of lime, copper sulfate, and CMC. The prepared material was then agitated with an Aerophine 3418A collector (selective with respect to pyrite and silica) and sent to the main zinc flotation. The tailings from the main zinc-pyrite flotation were agitated with copper sulfate, a collector (Aerophine 3418A) and a depressant (CMC), after which they were sent to control flotation.The froth product from the rough zinc flotation was contacted with lime in the presence of Aerophine 3418A and a depressant (CMC), after which it was sent to the first zinc cleaning unit. The tailings from the rough zinc flotation were agitated with copper sulfate, a collector (Aerophine 3418A), and a depressant (CMC), then sent to the scavenger zinc flotation unit. The concentrate from the scavenger zinc-pyrite flotation and the scavenger zinc flotation unit was returned to the rough zinc-pyrite flotation unit. The tailings from the first zinc cleaning unit were fed to the rough zinc flotation unit. The tailings from the scavenger zinc-pyrite flotation and the scavenger zinc flotation unit were waste. The froth product from the first zinc cleaning unit was subjected to the second and third zinc cleaning units in the presence of lime and CMC. The tailings from the 2nd zinc cleaning were sent to the feed of the 1st zinc cleaning, and the tailings from the 3rd zinc cleaning were sent to the feed of the 2nd zinc cleaning.The foam product of the third zinc refining was a finished (purified) zinc concentrate.

[0048] The experiment was conducted in a closed loop using the reagents used in the prototype method. The reagent consumption rates and mechanical attrition regime were preliminarily adjusted to optimize them for achieving the best flotation performance of the tested ore sample and producing high-quality concentrates. All operations—grinding, flotation, and mechanical attrition of middlings—were performed using standard laboratory equipment and standard methods.

[0049] The purified zinc concentrate obtained by the prototype method had the following chemical composition, wt. %: 50.41 zinc; 1.02 copper; 1.46 lead; 2.61 SiO2. The through extraction of zinc into the purified zinc concentrate was 86.23 wt. %. The regulated amount of impurities (Cu + Pb + SiO2) was 5.09 wt. %. According to the requirements of GOST R 54922-2012 "Zinc concentrates. Specifications", the concentrate corresponds to the KTs-3 brand (Zn ≥ 50.0 %; Cu ≤ 2.0 %; SiO2 ≤ 4.0 %). At the same time, according to a number of key parameters [SiO2 ≤ 1.5 %; (Cu+Pb+SiO2) ≤ 4.5%] the resulting zinc concentrate does not meet consumer requirements (Table 1, experiment 1).

[0050] Example 2 (Table 1, experiments 2-4 and 7) – the proposed method.

[0051] The initial feed, the general scheme of flotation enrichment and the reagent mode of copper-lead operations are the same as given in the description of the implementation of the proposed method on pp. 7-8 and the process flow chart in Figs. 1 and 2. The difference is that the enrichment scheme according to the proposed method excludes mechanical attrition operations, and the depressant claimed in the present invention, "RD 1033", was used as a depressant for silica-containing minerals of gangue instead of CMC. In this case, the mass ratio of the "RD 1033" depressant and the copper-containing activator of zinc sulfides was maintained equal to (0.1; 2.5; 5): 1. In experiments 2–4, copper sulfate was used as a copper-containing activator of zinc sulfides, and in experiment 7, nanosized copper oxyhydroxide CuO×nH2O was used with a mass ratio of the depressant “RD 1033” and nanosized copper oxyhydroxide equal to 2.5:1.

[0052] Analysis of the obtained results in comparison with the prototype (experiment 1) showed that:

[0053] - the through extraction of copper into total copper concentrate increased by 5.03-7.08% while simultaneously increasing the copper content in concentrate by 0.84-1.88%;

[0054] - the through extraction of lead into lead concentrate increased by 0.95-2.41% while simultaneously increasing the lead content in concentrate by 0.48-1.22%;

[0055] - the through extraction of zinc into purified zinc concentrate increased by 2.6-4.36%, while at the same time a significant increase in the zinc content in zinc concentrate was achieved - by 0.91-6.84%.

[0056] The obtained zinc concentrate meets the requirements of the KTs-2 brand (in the prototype experiment, a lower quality zinc concentrate of the KTs-3 brand was obtained). The purified zinc concentrates obtained by the proposed method (Table 1, experiments 2-4 and 7) meet the consumer's requirements both in terms of silicon dioxide content (0.75-1.44% obtained with the requirement of "no more than 1.5%) and in terms of the sum (Cu+Pb+SiO2): 3.22-4.24% obtained with the requirement of "no more than 4.5%). In the prototype method (experiment 1), the values ​​​​of these indicators do not meet the consumer's requirements: the purified zinc concentrate contained 2.61% SiO2 and 5.09% of the sum (Cu+Pb+SiO2). The flotation indices obtained using a combination of RD 1033 with copper sulfate (experiment 2) and a combination of RD 1033 with nanosized copper oxyhydroxide (experiment 7) under the same conditions (mass ratio 2.5:1) are close to and exceed similar indices obtained using the prototype (experiment 1, Table 1).

[0057] The results of experiments 2-4 and 7 confirm the possibility of obtaining a technical result in the entire declared range of ratios of the components of the depressant “RD 1033”, including the composition of the depressant in the absence of water (experiment 4).

[0058] Example 3 (Table 1, experiments 5 and 6) – extreme values ​​of mass ratios of depressant “RD 1033” and copper sulfate.

[0059] The initial feed, scheme and conditions of ore enrichment are the same as in example 2. The difference is that in experiment 5, a composition of reagents "RD 1033" and copper sulfate with an extremely high mass ratio (5.5:1) relative to the declared one was used, and in experiment 6, the same composition of reagents ("RD 1033" and copper sulfate) with an extremely low mass ratio - 0.07:1, respectively.

[0060] The results obtained in experiments 5 and 6 are close to similar results obtained using the prototype (Table 1, experiment 1). Analysis of the obtained results indicates that the flotation results at extreme mass ratios of the RD 1033 depressant and the copper-containing zinc sulfide activator (in this case, copper sulfate) are significantly lower than in Example 2 (Table 1, experiments 2-4 and 7), which used the same depressant ("RD 1033") with the declared range of ratios of the RD 1033 depressant and the copper-containing zinc sulfide activator - (0.1-5):1. The flotation indicators in Example 3 (Table 1, experiments 5 and 6) are close to similar indicators obtained in the prototype, Example 1 (Table 1, experiment 1). In terms of silicon dioxide content (1.58-2.46% SiO2), the purified zinc concentrates obtained in experiments 5 and 6 do not meet consumer requirements (SiO2≤ 1.5%).They also do not meet consumer requirements for the sum (Cu+Pb+SiO2), which in these experiments amounted to 4.78-5.12%, while ≤ 4.5% is required (Table 1, experiments 5 and 6).

[0061] Table 1

[0062]

[0063] Conditions and qualitative and quantitative indicators of flotation methods for sulfide zinc-containing ores of non-ferrous metals

[0064] Experiment number Way The mass ratio of the depressant "RD 1033" and the copper-containing zinc sulfide activator Product Exit, % Content, % Extraction, % Cu Pb Zn SiO 2 Cu+Pb+SiO 2 in zinc concentrate Cu Pb Zn SiO 2 1. Prototype - Copper concentrate (total) 3,03 19,32 6,74 8,68 4,89 - 69,71 11,60 4,03 0,36 Lead concentrate 2,49 2,53 47,15 16,52 2,75 - 7,50 66,59 6,31 0,16 Zinc concentrate 11,15 1,02 1,46 50,41 2,61 5,09 13,55 9,28 86,23 0,70 Flotation tailings (combined) 83,33 0,093 0,265 0,777 49,46 - 9,24 12,53 9,93 98,78 Source ore 100,00 0,84 1,76 6,52 41,73 - 100,00 100,00 100,00 100,00 2. Proposed "RD 1033": CuSO4 = 2.5: 1 Copper concentrate (total) 3,01 21,14 6,46 6,93 3,37 - 76,66 10,93 3,20 0,24 Lead concentrate 2,44 1,98 49,56 10,11 2,01 - 5,82 67,81 3,79 0,12 Zinc concentrate 10,30 0,80 1,63 57,21 0,87 3,30 9,97 9,45 90,52 0,21 Flotation tailings (combined) 84,25 0,074 0,250 0,194 49,34 - 7,55 11,81 2,51 99,43 Source ore 100,00 0,83 1,78 6,51 41,81 - 100,00 100,00 100,00 100,00 3. Proposed "RD 1033": CuSO4 = 5:1 Copper concentrate (total) 3,07 20,89 6,58 7,02 3,14 - 75,48 11,41 3,31 0,22 Lead concentrate 2,39 2,04 48,56 9,91 1,98 - 5,74 65,57 3,64 0,11 Zinc concentrate 10,37 0,84 1,68 55,68 0,75 3,27 10,25 9,84 88,83 0,19 Flotation tailings (combined) 84,17 0,086 0,277 0,326 49,38 - 8,53 13,18 4,22 99,48 Source ore 100,00 0,85 1,77 6,50 41,78 - 100,00 100,00 100,00 100,00 4. Proposed "RD 1033": CuSO4 = 0.1: 1 Copper concentrate (total) 3,04 20,16 6,78 7,24 3,66 - 74,74 11,78 3,40 0,27 Lead concentrate 2,44 2,31 48,10 10,24 2,10 - 6,87 67,07 3,86 0,12 Zinc concentrate 11,40 0,98 1,82 51,32 1,44 4,24 13,62 11,86 90,31 0,39 Flotation tailings (combined) 83,12 0,047 0,196 0,189 49,94 - 4,77 9,29 2,43 99,22 Source ore 100,00 0,82 1,75 6,48 41,84 - 100,00 100,00 100,00 100,00 5. The ratio of the depressant "RD-1033" to the copper-containing zinc sulfide activator is excessive (high) "RD 1033": CuSO4 = 5.5: 1 Copper concentrate (total) 2,73 21,68 6,33 6,89 3,18 - 70,46 9,82 2,89 0,21 Lead concentrate 2,46 2,42 47,81 10,48 1,97 - 7,09 66,82 3,96 0,12 Zinc concentrate 11,10 1,08 2,12 50,61 1,58 4,78 14,27 13,37 86,29 0,42 Flotation tailings (combined) 83,71 0,082 0,210 0,533 49,54 - 8,18 9,99 6,86 99,25 Source ore 100,00 0,84 1,76 6,51 41,78 - 100,00 100,00 100,00 100,00 6. Extreme (low) ratio of depressant "RD-1033" and copper-containing zinc sulfide activator "RD-1033": CuSO4 = 0.07: 1 Copper concentrate (total) 3,00 19,32 6,81 7,68 4,22 - 69,83 11,48 3,54 0,30 Lead concentrate 2,55 2,51 47,28 8,32 2,31 - 7,71 67,73 3,26 0,14 Zinc concentrate 11,88 1,01 1,65 49,54 2,46 5,12 14,46 11,01 90,40 0,70 Flotation tailings (combined) 82,57 0,080 0,211 0,221 50,11 - 8,00 9,78 2,80 98,86 Source ore 100,00 0,83 1,78 6,51 41,85 - 100,00 100,00 100,00 100,00 7. Proposed "RD-1033": nanosized copper oxyhydroxide (CuO×nH2O) = 2.5:1 Copper concentrate (total) 2,97 21,20 6,41 7,02 3,31 - 76,79 10,76 3,21 0,24 Lead concentrate 2,45 1,99 48,86 10,27 2,52 - 5,95 67,63 3,88 0,15 Zinc concentrate 10,27 0,81 1,60 57,25 0,81 3,22 10,14 9,28 90,59 0,20 Flotation tailings (combined) 84,31 0,069 0,259 0,179 49,31 - 7,12 12,33 2,32 99,41 Source ore 100,00 0,82 1,77 6,49 41,82 - 100,00 100,00 100,00 100,00

Claims

1. A method for flotation of zinc-containing sulfide ores of non-ferrous metals, including grinding, agitation, inter-cycle flotation of two or more metals in a lime medium with a collector, frother and depressor, regrinding of the zinc-containing product, flotation separation of zinc sulfides into a crude zinc concentrate using a copper-containing zinc sulfide activator, a collecting reagent, frother and depressor of silica-containing rock minerals, staged re-cleaning followed by flotation in a lime medium of the crude zinc concentrate to obtain purified zinc concentrate and separation of iron sulfides and silica-containing rock minerals into final tailings, characterized in that a depressor is used as a depressant reagent for silica-containing rock minerals in obtaining purified zinc concentrate, which is a mixture containing copolymers of acrylic and carboxylic acids, carboxylic acid anhydrides, polyhydric alcohols,polyorganosilicon compound, amines, taken respectively in the following weight ratio, wt.%:, copolymers of acrylic and carboxylic acids 5-30 carboxylic acid anhydrides 5-30 polyhydric alcohols 10-50 polyorganosilicon compound 10-50 amines 1-5, In this case, the depressant and the copper-containing activator of zinc sulfides are in a weight ratio of (0.1-5):1, respectively.

2. The method according to claim 1, characterized in that the depressant additionally contains water in an amount of up to 4% by weight.

3. The method according to claim 1, characterized in that copper sulfate CuSO4⋅5H2O or nanosized copper oxyhydroxide CuO⋅nH2O is used as the copper-containing activator of zinc sulfides.

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