RU2320423C2 - Method for flotation separation of sulfide copper-nickel pyrrhotine-bearing ores - Google Patents

Abstract

FIELD: concentration of minerals by froth flotation process, in particular, flotation separation of sulfide copper-nickel pyrrhotine-bearing ores, may be used in flotation concentration of other materials containing copper, nickel and iron minerals.

SUBSTANCE: method involves grinding ore; providing collective flotation in the presence of sulphydryl collectors to produce collective copper-nickel concentrate, nickel-pyrrhotine product and tailings; additionally grinding collective copper-nickel concentrate and providing staged conditioning of intermediate flotation products with sulfur-bearing reactants-modifiers, one of said modifiers containing sulfur in the form of sulfide and other modifier containing sulfur as part of sulfoxy complex; subjecting material pulp to intermediate aeration followed by flotation segregation of copper minerals into selective copper concentrate, said segregation process being carried out in the presence of sulphydryl collector; directing nickel-pyrrhotine product for flotation separation in the presence of reactant-medium regulator, sulphydryl collector and reactant-pyrrhotine depressor for producing of selective nickel concentrate and nickel-bearing pyrrhotine concentrate. Reactants-modifiers containing sulfur as part of sulfoxy complex are water-soluble inorganic and/or organic compositions containing chemical group SO₃H. Weight ratio of sulfide sulfur of one reactant-modifier to chemical group SO₃H of other reactant-modifier is 1:(0.5-14.5), and pH value at final conditioning stage is maintained within a range of from 5.9 to 8.2 units.

EFFECT: enhanced dumping of poor pyrrhotine into waste concentration product without increasing of valuable component losses.

5 cl, 15 ex

Description

The invention relates to the field of mineral processing by foam flotation, in particular to the flotation separation of sulfide copper-nickel pyrrhotite-containing ores, and can be used in flotation concentration of other polymetallic materials containing sulfide minerals of copper, nickel and iron.

A known method of flotation concentration of sulfide copper-Nickel ores, including fine grinding of the original ore, aeration of the pulp and sequential allocation of flotation selective copper, Nickel and pyrrhotite concentrates. In this case, flotation separation of copper minerals into the foam product is carried out using a complex of reagents: collector, blowing agent and inorganic modifier (depressor). Chamber intermediate product of the copper flotation cycle containing pentlandite, pyrrhotite and waste minerals is treated in a calcareous medium (pH = 10.5 units) with an alkaline salt of dithiocarbamic acid (MH carbamate), conditioned with a collector and a blowing agent, after which three stages of flotation are carried out: nickel, nickel-pyrrhotite and peer. As a result of 3 stages of flotation, three target pentlandite-containing products are obtained: selective nickel concentrate, "ordinary" pyrrhotite concentrate and nickel "head", which are combined with selective nickel concentrate and sent for processing to the pyrometallurgical processing (Rybas V.V., Ivanov V .A., Volkov V.I. et al. // Non-ferrous metals. - 1995. - No. 6. - P.37 ÷ 39).

The disadvantage of this method is that in it to achieve the regulatory "depth" of the disclosure of mineral complexes requires a very fine grinding of the original ore - to the content of 80-83% of the particle size class less than 44 microns. This causes the formation of a large amount of sludge in the flotation pulp, represented by the finest particles of valuable minerals - chalcopyrite, cubanite and pentlandite, which, being ineffectively extracted into concentrates, are lost with the waste products of enrichment (A.Abramov A.A. Technology of processing of oxidized and mixed non-ferrous metal ores .-- M .: Nedra, 1986. - S.23 ÷ 30).

In addition, the presence of sludge significantly degrades the selectivity of the flotation process as a result of the rapid oxidation of highly dispersed sulfides, the surface of which is coated with hydrophilic films. Coagulative adherence of sludge to the surface of sulfide particles leads to their hydrophilization, which causes inefficient flotation and causes an increase in the loss of valuable components with dump tailings. At the same time, the consumption of the collector absorbed by fine particles of minerals sharply increases (Plaksin I.N., Barsky L.A., Angelova S.M. Flocculation and flotation of phosphate sludge on a carrier concentrate. - In the book: Studies of the effects of flotation reagents. - M .: Science, 1968. - P.70 ÷ 78).

Another serious disadvantage of this method is the low extraction of valuable components in the target (copper and Nickel) concentrates. Upon receipt of high quality concentrates, a significant amount of nickel and precious metals (up to 30-35%) of their content in the ore goes into pyrrhotite concentrate, the processing of which using autoclave hydrometallurgy technology is associated with additional losses of non-ferrous and especially high losses of platinum metals. This disadvantage is largely due to the ineffective depression regime of pentlandite and pyrrhotite in the copper flotation cycle, where only one modifying reagent is used.

A known method of flotation concentration of sulfide copper-Nickel ores, in which copper minerals are allocated in the "head" of the process. In the known method, the initial ore is subjected to relatively "coarse" grinding - to the content of 55 ÷ 70% of the size class less than 44 microns. After that, aeration of the pulp is carried out in the presence of a collector and flotation of copper minerals in the presence of a collector and a blowing agent to obtain a rough copper concentrate. Blister copper concentrate is sent for purification, which is carried out with the addition of one modifier reagent containing sulfur in the sulfoxide complex. In this case, a finished copper concentrate is obtained. From the chamber product formed in the copper flotation cycle, sulfide minerals are isolated by collective flotation into a nickel-pyrrhotite product. At the same time, waste rock minerals are removed to the tailings. Collective flotation is carried out in a slightly alkaline medium (pH = 8.5 ÷ 9.5 units) in the presence of an organic sulfur-containing additive and collectors. Subsequent selective isolation of pentlandite and pyrrhotite to the target concentrates from the collective nickel-pyrrhotite intermediate is carried out in an alkaline medium (pH = 10.3 ÷ 10.5 units) after treatment of the pulp with dithiocarbamate, which acts as a low-nickel pyrrhotite depressor in this operation. As a result of this, a nickel concentrate and a pyrrhotite-containing product are obtained, from which, upon subsequent flotation carried out with the addition of a collector and dithiocarbamate, a finished nickel-containing pyrrhotite concentrate is isolated. The chamber product of the operation, low-nickel pyrrhotite, after combining with the tailings (common tails) is sent for storage (I.N.Khramtsova, A.A. Yatsenko, P.M. Baskaev, N.G. Kaitmazov, I.V. Volyansky, V.V. Gogotina // Non-ferrous metals. - 2001. - No. 6. - S.39 ÷ 40).

The disadvantage of this method is the relatively low quality of the obtained target concentrates. Moreover, an improvement in the quality of concentrates is inevitably accompanied by an increase in losses of non-ferrous and especially precious metals with dump tailings.

The unsatisfactory level of qualitative and quantitative characteristics of copper and nickel concentrates achieved in a known manner is due to the lack of a sufficiently effective controlling effect on the mechanism of depression of pyrrhotite. As a result of this, during ore flotation, this mineral is enriched in iron and sulfur enriched into finished concentrates. The pyrrhotite contained in concentrates causes additional emissions of sulfur dioxide during the oxidative smelting of concentrates, which degrades the environmental performance of copper-nickel ore processing. At the same time, the consumption of flux and oxygen in the metallurgical cycle increases, as well as the output of waste slag from metallurgical production and, accordingly, the level of losses of valuable components increases.

A known method of flotation concentration of sulfide copper-Nickel ores, which also applies only one reagent modifier containing sulfur in the sulfoxide complex. At the same time, carbothiosulfate, a product of the interaction of alkaline cellulose, sodium monochloracetate (or monochloracetic acid) and sodium thiosulfate, with the general formula: C ₆ H ₇ O ₂ (OH) _3-yz (OCH ₂ COONa) _y (S ₂ O ₃ Na) _z , where y is the degree of substitution for carboxymethyl groups (varies from 0.45 to 1.2); z - the same for thiosulfate groups (varies from 2.55 to 1.8). In the known method, the modifier is used as a suppressor of gangue (A.S. USSR No. 825160, class B03D 1/02, 07/22/07).

The main disadvantage of this method is the relatively low quality of the resulting copper concentrate and the increased transition of non-ferrous metals to pyrrhotite concentrate. When processing such concentrates in the metallurgical cycle, there is an increased yield of nickel slag, complicating the process of copper production, as well as a high level of irretrievable losses of non-ferrous (15-20%) and precious (30-40%) metals with ferrous tailings of the autoclave technology for processing pyrrhotite concentrates.

There is also a known method of flotation of sulfide copper-nickel ores, in which one modifier reagent is used containing sulfur in the sulfoxide complex — carbosulfite, which is the product of the interaction of alkaline cellulose, sodium monochloracetate (or monochloracetic acid) and sodium sulfite, with the general formula: C ₆ H ₇ O ₂ (OH) _3-yz (OCH ₂ COONa) _y (SO ₃ Na) _z , where y is the degree of substitution for carboxymethyl groups (varies from 0.45 to 1.2); z - the same for bisulfite groups (varies from 0.01 to 0.05). In this method, the modifier is also used as a gangue suppressor (A.S. USSR No. 831193, class B03D 1/02, 04/03/77).

A serious disadvantage of this method is the increased conversion of copper to nickel concentrate, which results in a significant increase in the cost of the metallurgical cycle in the processing of such concentrate and the relatively low level of overall profitability of the production of non-ferrous metals.

A known method of flotation of sulfide copper-Nickel ores, which uses a combination of 2 modifying reagents, both of which contain sulfur in the sulfoxide complexes. Iron (II) and (III) hydrosulfates are used as modifying reagents, i.e. Fe [H (SO ₄ ) ₃ and Fe [H (SO ₄ )] ₂ . Modifiers are used to increase the extraction of copper in the concentrate of the same name (A.S. USSR, No. 869817, class B03D 1/02, 16.11.79).

The disadvantage of this method is the high consumption of reagent modifiers: 2-5 kg / t of the original ore. This significantly increases the cost of ore dressing and requires significant investment in the construction of an industrial plant for the reception, storage, preparation and dosage of modifying reagents in the flotation process.

Another disadvantage of this method is that the resulting copper concentrate contains an increased percentage of pentlandite and pyrrhotite. This, on the one hand, leads to a high level of operating costs in the metallurgical industry, and on the other, it further complicates the problem of utilizing sulfur dioxide from waste metallurgical gases and reducing the loss of valuable metals with waste slag.

A known method of flotation concentration of sulfide copper-Nickel ores, which uses a combination of 2 modifying agents. At the same time, both modifier reagents contain sulfur in various sulfoxide complexes: sulfate - CuSO ₄ and sodium thiosulfate - Na ₂ S ₂ O ₃ in the ratio 1: (1 ÷ 5). In the known method, modifiers are used to activate copper and nickel sulfides (AS USSR No. 839573, CL B03D 1/02, 05/12/07).

The main disadvantage of this method is its low selectivity. The resulting concentrates contain an increased percentage of pyrrhotite, which determines the low level of environmental purity of metallurgical production and significant losses of valuable components with waste slag from smelting units.

In addition, selective copper and nickel concentrates contain a significant percentage of “second” metals, which leads to a high level of operating costs in the processing of concentrates in the metallurgical production cycle.

The closest in combination of features and the achieved result to the proposed method is a flotation separation method for sulfide copper-nickel pyrrhotite-containing ores, including ore grinding, collective flotation in the presence of sulfhydryl collectors with preliminary production of a collective copper-nickel concentrate, nickel-pyrrhotite product and tailings. Copper-nickel concentrate is subjected to subsequent regrinding to a content of 90% class less than 44 microns, the prepared material is aerated in the presence of a collector and a modifying reagent containing sulfur in sulfide form. The selective separation of copper and nickel minerals is carried out in a highly alkaline medium after treatment of the pulp with a modifying reagent containing sulfur in the sulfoxide complex and a collector. At the same time, sodium sulfide - Na ₂ S is used as a modifying reagent containing sulfur in sulfide form, and sodium sulfite (middle salt) - Na ₂ SO _{3 is} used as a modifying reagent containing sulfur in the sulfoxide complex (Blatov I.A. Enrichment of copper-nickel ores. - M .: State Unitary Enterprise Publishing House "Ore and Metals", 1998. - S.98 ÷ 99) - prototype.

An important advantage of the prototype method is the possibility of relatively coarse grinding of the original ore (up to 80% of the size class less than 74 microns), which minimizes the output of sludge fractions. In addition, the prototype provides selective separation of the bulk of the minerals of copper and nickel in the collective concentrate directly in the "head" of the process. The removal at this stage of the process by the chamber product of most of pyrrhotite and gangue eliminates their negative effect during the selective separation of copper minerals from collective copper-nickel concentrate.

However, the known method also has a number of significant disadvantages. The main one is the relatively low contrast of the flotation properties of the shared minerals - the basic copper sulfides (chalcopyrite, cubanite) and pentlandite - at the stage of selection of collective copper-nickel concentrate. The consequence of this is the low ratio of the mass fraction of copper to nickel in the resulting selective copper concentrate. When the copper content in the foam product is at the level of 29.30%, the mass fraction of nickel in it is 1.93%.

The increased nickel content in copper concentrate - a factor that significantly increases the metallurgical redistribution - is caused, on the one hand, by the use of an insufficiently effective modifying reagent (sodium sulfite) in the copper flotation cycle, on the other hand, the absence (weak manifestation) of the synergistic effect of positive interaction of the reagents modifiers.

Another disadvantage of the known method is that the nickel concentrate obtained has an extremely low nickel content not exceeding ~ 4%, which, apparently, is associated with a rather high non-target extraction of nickel minerals in copper concentrate. At the same time, the extraction of non-ferrous metals from the collective concentrate to the target selective concentrates is relatively low, rel.% (From the operation): copper to copper - 88.6; nickel to nickel - 79.9.

In order to increase the contrast of the flotation properties of copper and pentlandite minerals, which is necessary for their subsequent effective separation during selective flotation, a directed physicochemical effect on the mineral complexes is required taking into account the nature of the newly formed products covering the particle surface.

The problem solved by the invention is to obtain high-quality selective copper and nickel concentrates isolated in the technology of separation of sulfide copper-nickel pyrrhotite-containing ores, while increasing the completeness of the target extraction of non-ferrous metals in them, due to a deeper withdrawal of poor pyrrhotite in the waste product without increasing loss of valuable components.

The technical result from the use of the invention is to increase the productivity of the head processing of the pyrometallurgical production for the production of non-ferrous metals, reduce material costs for the production of copper and nickel, reduce emissions of sulfur dioxide per tonne of produced metals by increasing the depth of sulfur and iron output to the tailings, simplifying the system for utilization of dioxide sulfur, as well as reducing losses of non-ferrous and precious metals with waste tailings in the metallurgical industry with tvalnymi slags.

The problem is solved in that in the method of flotation separation of sulfide copper-nickel pyrrhotite-containing ores, including ore grinding, collective flotation in the presence of sulfhydryl collectors to obtain a collective copper-nickel concentrate, nickel-pyrrhotite product and rock tailings, regrinding of collective copper-nickel concentrate postadial conditioning of intermediate flotation products with sulfur-containing modifying reagents, one of which contains sulfur in sulfide in the other form, as a part of the sulfoxide complex, the intermediate aeration of the pulp and the subsequent separation of copper minerals by flotation in the presence of a sulfhydryl collector into a selective copper concentrate, flotation separation of the nickel-pyrrhotite product in the presence of a medium-control reagent, a sulfhydryl collector and pyrrhotin depressant reagent obtaining selective Nickel concentrate and Nickel-containing pyrrhotite concentrate according to the invention as a modifying reagent containing sulfur composed sulfoxide complex, are water-soluble inorganic and / or organic compounds containing in their structure chemical group SO ₃ H, wherein the weight ratio of sulfide sulfur of one reactant modifier to a chemical group SO ₃ H the other reactant modifier is 1: (0, 5 ÷ 14.5), and the pH value at the final stage of conditioning is maintained in the range of 5.9 ÷ 8.2 units.

Another difference of the method is that, as a modifying reagent containing sulfur in the form of a sulfide ion, polysulfides of alkali and / or alkaline earth metals are used.

A further difference of the method is that alkali and / or alkaline earth metal bisulfites are used as an inorganic compound containing the chemical group SO ₃ H.

Another difference of the method is that as an organic compound containing the chemical group SO ₃ H in its composition, water-soluble sulfonic acids are used.

Another difference of the method is that the polysulfides of alkali and / or alkaline earth metals are used in the composition of polysulfide-thiosulfate solutions obtained by the interaction of sulfides of alkali and / or alkaline earth metals, as well as their oxides, hydroxides and complex alkaline salts with elemental sulfur.

It was experimentally established that to achieve this goal can be achieved by simultaneously creating several conditions:

- the use in the conditioning process of intermediate flotation products of 2 or more modifier reagents, the combination of which at a certain ratio provides a synergistic effect;

- the use of a modifying reagent based on water-soluble inorganic and / or organic compounds containing the chemical group SO ₃ H;

- the associated supply of modifying reagents used at different stages of the conditioning process of intermediate flotation products, while ensuring their balanced effect on the surface of the separated minerals;

- the creation at the final stage of conditioning a certain pH value of the pulp (in the range of 5.9 ÷ 8.2 units).

The observed effect of a significant increase in flotation contrast, manifested in copper and nickel sulfides as a result of the sequential use of two different sulfur-containing modifying reagents, one of which contains the chemical group SO ₃ H in its composition, is unexpected. In the prototype method, such a rapid increase in contrast is not observed.

For modifiers containing alkali and / or alkaline earth metal bisulfites synthesized based on inorganic compounds, this effect can be explained based on the following theoretical concepts.

It is well known that in the process of selective separation of sulfide mineral complexes with similar physicochemical characteristics, the chemical modification of the surface, which creates the necessary technological contrast of the separated minerals, is key (Lisichkin G.V. Chemical modification of the surface of mineral substances // Soros Educational Journal. - 1996. - No. 4. - S.52-59). The modifier molecule must contain a fragment whose properties must be reported to the mineral. This may be a certain group designed to bind or chelate a metal ion; hydrocarbon radical providing hydrophobicity of the mineral; a transition metal complex having catalytic activity; acidic or basic ion exchanger group; stable free radical that will break off radical chain processes, etc. In addition to this functional part, the modifier molecule must also contain the so-called anchor group, i.e. the fragment responsible for binding the functional part of the modifier to the surface of the mineral carrier (substrate).

The conducted studies have allowed us to establish that the combined modifier, which includes the multivalent sulfur compounds: sulfide and sulfoxide groups, is better than other tasks. At the same time, the highest mineral selection indicators are ensured when using compounds containing the HSO ₃ group as a sulfoxide modifier.

In the proposed method for the separation of copper-nickel pyrrhotite-containing ores, the first stage of conditioning the collective concentrate, preceding the separation flotation of copper and nickel minerals, is carried out in the presence of a depressant modifier reagent - sodium sulfide. The use of a depressant is necessary for the selective suppression of the flotation of pentlandite and pyrrhotite.

When sodium sulfide is added to the pulp, hydrolysis reactions proceed:

During hydrolysis, hydrosulfide ion (HS ^- ), hydroxyl ion (OH ^- ) and hydrogen sulfide (H ₂ S) are formed.

In this case, sodium sulfide and caustic soda dissolve hydrophobic films of elemental sulfur, which form on the surface of pentlandite and pyrrhotite particles as a result of their oxidation during flotation with atmospheric oxygen. Elemental sulfur films cause an increase in the flotation activity of pentlandite and pyrrhotite, causing a loss in the natural contrast of these minerals with respect to copper sulfides.

The process of dissolution of elemental sulfur on the surface of pentlandite and pyrrhotite, which ensures a decrease in their flotation activity, proceeds according to the equations:

where n is the number of attached sulfur atoms (varies from 2 to 4).

During flotation, sulfide ions are oxidized with atmospheric oxygen. In this case, various forms of sulfide ions - sulfide, hydrosulfide and polysulfide - are oxidized by the reactions:

Due to the oxidation of sulfide ions and a decrease in their concentration in the treated pulp, the depression of pentlandite and pyrrhotite decreases. The effect of weakening the depression of pentlandite and pyrrhotite is further enhanced by the fact that thiosulfate ions formed by reactions (6) ÷ (8) during the oxidation of sulfide sulfur are activators for these minerals. Thus, a double function of sodium sulfide is revealed: in the initial period of its supply to the technological process, it ensures depression of pentlandite and pyrrhotite, and as a result of oxidation, it activates previously suppressed minerals with an increase in their flotation activity.

Therefore, to obtain a high-quality concentrate, it is necessary to maximize the flotation rate of copper-containing minerals so that they can be more fully extracted into the foam layer (concentrate) before the oxidation of sodium sulfide. Otherwise, there is a co-extraction of impurities and a decrease in the quality of the allocated copper concentrate. For this purpose, a reagent is released into the process, which releases bisulfite ion during dissolution, which provides a higher activity of copper minerals in comparison with the flotation of competing minerals.

In some methods, a sulfoxide inorganic reagent modifier sodium sulfite is used for this purpose.

The literature data on the use of modifying reagents based on water-soluble sulfoxide complexes (S _x O _at ^n- ), in particular sulfite and bisulfite ions, are fragmented and contradictory. So, for example, a known method of flotation separation of copper-Nickel concentrates in the pH range of 3-7 units. using sulfoxide modifiers - sulfite or alkali metal bisulfite, introduced into the process before pulp aeration. Moreover, in the known method, sulfoxide compounds are not used to activate copper minerals, as they are used in the proposed method, but in the exact opposite way, as suppressors of flotation of copper sulfides (US Patent No. 1549959, Cl. B03D 1/14, 209-167, 01.10. 84).

It was experimentally established that when using sodium sulfite (Na ₂ SO ₃ ), a certain positive effect is achieved, but the resulting copper concentrate contains at least 1.5% nickel. When it is processed at the conversion stage, this leads to the formation of a large volume of dry rolled slag, the transportation and processing of which is associated with high operating costs.

Studies have shown that the replacement of sodium sulfite with bisulfite, all other things being equal, significantly improves the quality of the resulting copper concentrate:

- the nickel content is reduced from 1.5-1.9 to 0.5-0.7%;

- the copper content in the concentrate rises from ~ 28 to 29-30%.

At the same time, high recovery of copper minerals in the concentrate of the same name is achieved - not less than 80%, which, in turn, allows to improve the quality of nickel concentrate, increase the depth of the output of low-nickel pyrrhotite into the tailings without increasing the loss of valuable components. Improving the quality of target concentrates reduces their total weight, and this reduces the capital intensity of metallurgical processes, reduces the industrial load on the industrial area and, thereby, improves the environmental safety of production by reducing sulfur dioxide emissions into the atmosphere.

The achieved result, apparently, can be explained by the difference in the chemical properties of sodium sulfite and sodium bisulfite. In particular, when sodium sulfite (middle salt) is introduced into the flotation pulp, the pulp pH rises to 9.5-10.5 units. In the case of using an additive of sodium bisulfite (acid salt), this indicator is 5.9-8.2 units. In the variant with bisulfite, flotation is carried out in a more acidic medium, and at that moment when intense separation of colloidal dispersed sulfur occurs (Shubov L.Ya., Ivankov S.I., Shcheglova N.K. Flotation reagents in the processes of mineral processing: Reference: In 2 books / Under the editorship of L.V. Kondratyeva. - M .: Nedra, 1990. - Book 1. - P.24-26).

This factor has a positive effect on the dispersion of air bubbles in the pulp and, as a consequence, on the improvement of the flotation kinetics of copper minerals. This is due to the fact that when sodium bisulfite is introduced into the flotation process, not only colloidal dispersed sulfur is released, but also its stabilization. And this, in turn, helps to increase the dispersion of air bubbles and the intensity of the formation of flotation complexes. In the alkaline medium characteristic of sodium sulfite, the sulfur formed rapidly dissolves, which negatively affects the flotation rate of copper sulfides and, as a result, significantly reduces the contrast of flotation properties of the separated minerals. That is why the use of sodium bisulfite as a modifier is more preferable than the middle salt (sulfite).

The advantage of sodium bisulfite also lies in the fact that it destroys thiosulfate ions, thereby eliminating the activation factor of impurity minerals (pentlandite, pyrrhotite), and at the same time allows the formation of colloidal dispersed sulfur in the pulp.

The interaction of water-soluble bisulfite ions (HSO ₃ ^- ) with unsaturated sulfoxide compounds formed during the oxidation of sodium sulfide proceeds, presumably, according to the following reactions:

The total speed of the process, as shown by the research results, increases with decreasing pH of the pulp solution. Moreover, the lower the pH, the more elemental sulfur is released. At the same time, the pH value and the concentration of bisulfite ions in the pulp must be compromised in order to maintain the balance of two oppositely directed processes. On the one hand, it is necessary to ensure that adsorbed sulfide ines are preserved on the surface of pentlandite and pyrrhotine particles to suppress their flotation activity, on the other hand, to prevent the dissolution of elemental sulfur and a decrease in the flotation rate of copper minerals.

Thus, the pH of the pulp has a complex effect on the state of the substances dissolved in the pulp and the physicochemical properties of the surface of the separated minerals. It was experimentally established that the optimal pH range for solving this goal is in the range of 5.9-8.2 units. FIELD optimal pH ensures conditioned pulp while maintaining the optimum ratio of sulfide ions and a chemical group SO ₃ H.

The mechanism of action of modifying reagents based on organic compounds containing the chemical group SO ₃ H has not yet been explained. Unexpected was the fact that this group, consisting of organic compounds of various nature, acts equally effectively, regardless of the organic radical. Experimental verification of organic products of petrochemical, synthetic and plant origin with various radicals showed similar results. The following were tested: phenolsulfonic acid, alkylphenolsulfonic acid, a mixture of alkylarylsulfonic acids (R is an alkyl radical containing 5-11 carbon atoms), amidosulfonic acid (NH ₂ -SO ₃ H), cellulose ethanesulfonic acid and other organic sulfonic acids and their salts.

I have not yet found my explanation for another, first discovered technological effect: in the process of creating the invention, a rather close efficiency of inorganic and organic modifying reagents based on compounds containing the chemical group SO ₃ H was established. And this despite the difference in the internal structure of chemical bonds and the valency of the incoming its composition is sulfur.

Surprisingly also appeared and the effect of mutual reinforcement of inorganic and organic reagents modifiers based on compounds containing the chemical group SO ₃ H, by using mixtures thereof.

Studies have shown that sulfides and / or polysulfides of alkali and / or alkaline earth metals can be effectively used as a modifying reagent containing sulfur in the form of sulfide ions.

Studies using sodium sulfide, as well as polysulfides of alkali and alkaline earth metals in the composition of polysulfide-thiosulfate solutions. Polysulfide-thiosulfate solutions were obtained by the interaction of sodium sulfide and calcium sulfide, as well as technical lime, caustic soda, industrial soda, Portland cement clinker and belite (nepheline) sludge with elemental sulfur (sulfur liquor and calcareous broth - ISO).

The key factors determining the technological parameters of flotation are the ratio of sulfide ions and the chemical group SO ₃ H introduced into the conditioning process as part of modifying reagents, and maintaining the optimal pH level at the final stage of the process. A specific ratio of modifiers is selected empirically, varying their costs depending on the regulatory qualitative and quantitative indicators of the resulting selective concentrates.

It was experimentally established that the optimal range of the mass ratio of sulfide ions and the chemical group SO ₃ H is in the range 1: (0.5–14.5), and pH = 5.9–8.2 units.

Outside of these ranges, the results of selective flotation of copper and nickel minerals are significantly reduced. So, with a mass ratio of sulfide ions and the chemical group SO ₃ H above the upper limit, more than 1: 0.5 (a modifier containing sulfide ion dominates) and a pulp pH above 8.2 units. deteriorates the quality of the copper concentrate compared with the prototype method. In copper concentrate, the content of nickel-bearing minerals - pentlandite and nickel-enriched pyrrhotite increases, due to a deficiency of the sulfoxide-type modifier reagent. It was shown above that this, on the one hand, reduces the flotation activity of copper-containing minerals, and on the other hand, as a result of the “thiosulfate” activation of impurity minerals, their flotation rate increases significantly. For this reason, the difference in the flotation rate of copper and nickel-containing minerals is sharply reduced and, as a consequence, the selectivity of the process.

With an extremely low mass ratio of sulfide ions and the chemical group SO ₃ H, less than 1: 14.5 (the modifier containing the chemical group SO ₃ H dominates) and the pulp pH is below 5.9 units. also there is a decrease in the quality of copper concentrate compared with the range of optimal values. Under these conditions, the contrast of the flotation properties of the separated minerals decreases due to the fact that the flotation rate of copper-containing minerals although increases, but at the same time there is a faster growth of the flotation rate of pentlandite and pyrrhotite as a result of chemical destruction of the previously adsorbed sulfide ions on the surface of their particles. In addition, with an excessively high consumption of a modifying reagent containing the SO ₃ H chemical group, at the subsequent stage of the separation of the nickel-pyrrhotite product, problems arise associated with the need for a high consumption of a medium-regulating reagent (lime) and intensive overgrowth of the internal elements of the equipment with calcium salt deposits .

Information on the use of the proposed technical solution in the flotation separation of sulfide copper-nickel pyrrhotite-containing ores in the study of scientific, technical and patent literature has not been identified, which indicates the compliance of the proposed method with the criterion of "Inventive step".

The method is as follows.

The initial copper-nickel pyrrhotite-containing ore is ground to a content of 65-75% of the fineness class of less than 44 μm using recycled water and collective flotation of copper-nickel minerals is carried out in the presence of sulfhydryl collectors — butyl sodium dithiophosphate and xanthate. In this case, a collective copper-nickel concentrate, a nickel-pyrrhotite product, and rock tails are obtained. Collective copper-nickel concentrate is subjected to regrinding to the content of 85-95% particle size class less than 44 microns, intermediate pulp aeration is carried out and copper minerals are subsequently extracted by flotation in the presence of sulfhydryl collector into selective copper concentrate. Intermediate flotation products are subjected to postadial conditioning with sulfur-containing modifying reagents, one of which contains sulfur in sulfide form, and the other in the sulfoxide complex. The resulting nickel-pyrrhotite product is sent to a flotation separation operation carried out in the presence of a medium control reagent, a sulfhydryl collector and pyrrhotite depressant reagent with the release of selective nickel concentrate and nickel-containing pyrrhotite concentrate. As a modifying reagent containing sulfur in the sulfoxide complex, water-soluble inorganic and / or organic compounds containing the chemical group SO ₃ H are used. The mass ratio of sulfide sulfur of one modifying reagent to the chemical group SO ₃ H of another reagent -modifier is 1: (0.5 ÷ 14.5). The pH at the final stage of conditioning is maintained in the range of 5.9-8.2 units.

As a modifying reagent containing sulfur in the form of a sulfide ion, polysulfides of alkali and / or alkaline earth metals can be used, for example, in the composition of polysulfide-thiosulfate solutions obtained by the interaction of sulfides of alkali and / or alkaline earth metals, as well as their oxides, hydroxides and complex alkaline salts with elemental sulfur. It is possible to use complex alkaline salts, which, when interacting with water, release free hydroxyl ions, as well as hydroxide and / or calcium oxide in a free or chemically bound state; two and / or tricalcium silicates; belitic sludge, and / or Portland cement clinker, and / or other products containing them.

Another difference of the method is that as an inorganic compound containing the chemical group SO ₃ H, alkali and / or alkaline earth metal bisulfites are used, for example, sodium and calcium bisulfites obtained by treating solutions of soda and caustic soda or a suspension of lime gaseous sulfur dioxide. In this case, sulfur dioxide can be used as part of the waste metallurgical gases.

Another difference of the method is that as an organic compound containing the chemical group SO ₃ H in its composition, water-soluble sulfonic acids are used. In particular, can be used:

- phenolsulfonic acid;

- a mixture of alkylarylsulfonic acids;

where R is an alkyl radical containing 5-11 carbon atoms.

amidosulfonic acid;

NH ₂ -SO ₃ H

cellulose ethanesulfonic acid (cellulose ether and ethanesulfonic acid)

where n = 200-600,

and other organic sulfonic acids. Sulfonic acids are obtained by the sulfonation of organic compounds — by treating them with strong sulfuric acid or sulfur trioxide.

Thus, both options for the production of a modifying reagent containing the SO ₃ H chemical group allow for the simultaneous utilization of sulfur from waste metallurgical gases, which makes it possible to solve a complex environmental problem.

Depending on the characteristics of flotation, the supply of reagents can be concentrated or fractional.

Flotation products undergo volume and weight measurements, are tested and analyzed. Based on the results of analyzes and measurements, the material balance of the enrichment process is calculated.

The proposed method is described in specific examples, and its result is shown in the table.

The experiments were carried out on industrial sulfide copper-nickel pyrrhotite-containing ore, which is being processed at the Talnakh processing plant (PF) of the Norilsk Nickel Mineral Processing Plant OJSC. The content of the main components in the initial ore was,%: 2.60 nickel; 3.91 copper; 24.02 sulfur.

Example 1 (experiment 1 of the table) - the implementation of the prototype method.

The initial sample of copper-nickel ore was ground to a content of 70% fineness class less than 44 μm using TOF reverse water at a ratio of W: T = 1.5: 1 and collective flotation was performed for 15 minutes in the presence of sulfhydryl collectors - potassium butyl xanthate (30 g / t) and sodium butyl aeroflot (10 g / t). The resulting collective concentrate was cleaned for 7 minutes. Then the material was regrind to the content of 90% of the size class less than 44 microns. The pulp was conditioned for 10 minutes with butyl aeroflot and modifying reagent sodium sulfide (180 g / t) and activated carbon (170 g / t), after which it was subjected to 10-minute aeration and the main copper flotation was carried out. The copper flotation process was carried out with the supply of a sulfoxide reagent modifier - sodium sulfite solution (400 g / t). The isolated blister copper concentrate was purified in two stages in the presence of lime (200 g / t) and sodium sulfite (60 g / t) in the first, 60 and 40 g / t in the second, respectively, to obtain the finished copper concentrate. At the same time, a collector, butyl aeroflot (1 g / t), was supplied at the final stage of flotation. The tailings of the first copper re-flotation flotation were subjected to control flotation without reagents. The control flotation chamber product was combined with the tails of the main copper flotation and a finished nickel concentrate was obtained. Collective copper-nickel flotation tails were directed to control flotation, which was carried out for 15 minutes in the presence of butyl xanthate (40 g / t) and butyl aeroflot (30 g / t). The concentrate was combined with the tails of copper-nickel stripping and nickel-pyrrhotite flotation was carried out with the same collectors supplied at a flow rate of 30 and 7 g / t, respectively. The rough nickel-pyrrhotite concentrate was refined without reagents and nickel-pyrrhotite concentrate was obtained. The tails of the control flotations were combined and common tails were obtained.

The efficiency of the flotation regime was evaluated by the chemical composition of the products obtained, the level of extraction of non-ferrous metals in copper, nickel and pyrrhotite concentrates, the irretrievable loss of valuable components with dump tailings.

The results of the experiment are shown in the table. The metal content in selective concentrates was,%: in nickel - 9.21 nickel and 3.94 copper; in copper concentrate - 1.52 nickels and 28.17 copper. The following metal extraction was obtained,%: in nickel concentrate - 71.64 nickels and 20.55 copper; 6.18 nickel and 76.81 copper in copper concentrate. The yield of total tails was 60.39%. Losses of valuable metals with common tails were equal,%: 12.89 nickels; 1.59 copper. The recovery of sulfur in the tailings amounted to 45.29%.

Example 2 (experiment 2 tables) - the proposed method.

The composition of the feed is the same as in example 1.

The initial copper-nickel pyrrhotite-containing ore was ground to a content of 70% fineness class less than 44 μm using TOF reverse water at a ratio of W: T = 1.5: 1, after which collective flotation of copper-nickel minerals was carried out in the presence of sulfhydryl collectors - butyl sodium dithiophosphate (20 g / t) and xanthate (6 g / t) to obtain a collective copper-nickel concentrate and nickel-pyrrhotite product. The resulting collective concentrate was refined to a 90% fineness class content of less than 44 microns, and then conditioned with sodium sulfide (600 g / t) and activated carbon (170 g / t). Prepared for separation, the copper-nickel concentrate was aerated for 10 minutes, then flotation, carried out in the presence of a sulfhydryl collector, separated copper minerals into a foam product - blister copper concentrate. The obtained crude copper concentrate was conditioned with two modifying reagents — sodium sulfide and sodium bisulfite, while maintaining the mass ratio of sulfide and bisulfite ions (chemical group SO ₃ H) equal to 1: 7.5, and subjected to two-stage purification. The costs of sodium sulfide and sodium bisulfite in the first recycle copper flotation were 200 and 2360 g / t, in the second - 100 and 1170 g / t, respectively. At the same time, at the final stage of conditioning, the pH was maintained at the level of 7.1 units. Sodium bisulfite was obtained by a known method by treating a soda solution with sulfur dioxide.

The nickel-pyrrhotite product obtained in the copper-nickel operation entered the collective nickel-pyrrhotite flotation cycle, which was carried out with the addition of DP-4 (25 g / t) and collectors: butyl xanthate (130 g / t) and aeroflot (15 g / t) in a slightly alkaline environment. As a result, collective nickel-pyrrhotite concentrate was obtained, and tailings were isolated with a chamber product. The resulting collective concentrate was refined to 88% of a grade of less than 44 μm, after which this product was subjected to preliminary alkaline treatment (pH = 10.2 ÷ 10.5) to depress pyrrhotite sulfides and pentlandite was flotated in the presence of sodium dithiocarbamate (250 g / t), resulting in a rough nickel concentrate and poor pyrrhotite product 1.

The rough nickel concentrate was combined with a chamber nickel-pyrrhotite product of copper selection and sent for a cleaning operation, which was carried out after conditioning the pulp for 10 minutes with sodium dithiocarbamate (200 + 100 g / t). As a result, a rough nickel concentrate and a nickel-pyrrhotite product were obtained, from which, upon supply of sodium dithiocarbamate (50 g / t) and butyl xanthate (25 g / t), the finished pyrrhotite concentrate and poor pyrrhotine product 2 were isolated. The resulting rough concentrate after processing lime pulps to pH = 10.2 ÷ 10.5 units. in the presence of sodium dithiocarbamate (200 + 200 + 150 g / t) was subjected to a second purification. After combining the crude concentrates, a finished nickel concentrate was obtained.

The selected reagent mode ensured the production of high-quality selective concentrates with at the same time high targeted recovery of valuable metals and a deep removal of sulfur in the tailings.

The results of the experiment are shown in the table. The metal content in selective concentrates was,%: in nickel - 10.31 nickel and 3.35 copper; in copper concentrate - 0.71 nickel and 29.22 copper. The following metal recovery was achieved,%: in nickel concentrate - 80.19 nickel and 17.39 copper; 2.93 nickels and 80.56 copper in copper concentrate. The yield of total tails was 64.97%. Losses of valuable metals with common tails remained at the prototype level,%: 12.72 nickel; 1.58 copper. The extraction of sulfur in the tailings increased compared with the prototype by 5.0% and amounted to 50.29%.

Example 3 (experiments 7-9 tables) - the proposed method.

The initial nutrition, scheme and conditions for the separation of copper-nickel pyrrhotite-containing ore are the same as in example 2. The difference is that sodium and calcium polysulfides composed of: sulfur liquor were used as a modifying reagent containing sulfur in the form of a sulfide ion (experience 7); calcareous broth (experiment 8); polysulfide-thiosulfate reagent obtained on the basis of belite (nepheline) sludge (experiment 9). These reagents containing polysulfides were obtained by hydrochemical treatment of elemental sulfur with a respectively hot sodium hydroxide solution, a suspension of hydrated lime, and a pulp of crushed belitic sludge. When conditioning the intermediate flotation products, the ratio of sulfide and bisulfite ions was 1: 7.5, and the pH at the final stage of conditioning was maintained at 7.1 units.

The results of the experiments are shown in the table. The obtained indicators are similar in level of experiment 2 (example 2) and significantly exceed the indicators obtained by the prototype method (experiment 1). The metal content in selective concentrates was,%: in nickel - 10.13 ÷ 10.36 nickel and 3.31 ÷ 3.48 copper; in copper concentrate - 0.69 ÷ 0.73 nickel and 29.02 ÷ 29.08 copper. Metal extraction achieved,%: in nickel concentrate - 79.60 ÷ 79.96 nickel and 17.32 ÷ 17.96 copper; in copper concentrate - 2.87 ÷ 3.02 nickel and 79.92 ÷ 80.69 copper. The yield of total tails was 64.21 ÷ 67.76%. Losses of valuable metals with common tails remained at the prototype level,%: 12.61 ÷ 12.89 nickel; 1.56 ÷ 1.60 copper. Extraction of sulfur in tailings increased compared with the prototype, amounting to 50.06 ÷ 50.31%.

Example 4 (experiment 10 of the table) - the proposed method.

The initial nutrition, scheme and conditions for the separation of copper-nickel pyrrhotite-containing ore are the same as in example 2. The difference is that calcium bisulfite was used as a modifying reagent containing sulfur in the sulfoxide complex. A calcium bisulfite pulp was prepared by treating a slurry of slaked industrial lime with sulfur dioxide. When conditioning intermediate flotation products, the ratio of sulfide and bisulfite ions was maintained at 1: 7.5, and the pH value at the final stage of conditioning was 7.1 units.

The results of the experiment are shown in the table. The results obtained are close to those achieved in experiments 2 and 7-9, carried out using sodium bisulfite. They also significantly exceed the indicators obtained by the prototype method (experiment 1). The metal content in selective concentrates was,%: in nickel - 10.29 nickel and 3.48 copper; in copper concentrate - 0.72 nickel and 29.24 copper. Metal extraction achieved,%: in nickel concentrate - 80.34 nickels and 18.11 copper; 2.95 nickels and 80.00 copper in copper concentrate. The yield of total tails was 65.41%. Losses of valuable metals with common tails are close to the level of the prototype,%: 12.81 nickel; 1.59 copper. The extraction of sulfur in the tailings amounted to 50.67%, which is 5.38% higher than in the prototype method.

Example 5 (experiments 11-13 table) - the proposed method.

The feed, scheme and conditions for the separation of copper-nickel pyrrhotite-containing ore are the same as in example 2. The difference is that as a modifying reagent containing sulfur in the sulfoxide complex, water-soluble sulfonic acids were used: amidosulfonic acid (experiment 11) ; a mixture of alkylarylsulfonic acids with an alkyl radical containing 5-11 carbon atoms (experiment 12); cellulose ethanesulfonic acid (experiment 13). These reagents were obtained by treating the corresponding organic products with gaseous sulfur trioxide (sulfonation method). When conditioning the intermediate flotation products, the mass ratio of sulfide sulfur to the chemical group SO ₃ H in modifying reagents was 1: 7.5, and the pH value at the final stage of conditioning was 7.1 units.

The results of the experiment are shown in the table. The results obtained are close to those achieved in experiments 2 and 7-10, carried out using inorganic reagents (bisulfites) containing in their composition the chemical group SO ₃ H. The proposed method and in these experiments significantly exceeds the indicators obtained by the prototype method ( experience 1). The metal content in selective concentrates was,%: in nickel - 10.18 ÷ 10.38 nickel and 3.47 ÷ 3.69 copper; in copper concentrate - 0.69 ÷ 0.72 nickel and 28.77 ÷ 29.08 copper. Metal extraction achieved,%: in nickel concentrate - 79.32 ÷ 80.30 nickel and 17.97 ÷ 19.05 copper; 2.82 ÷ 3.00 nickels and 79.04 ÷ 80.04 copper in copper concentrate. The yield of total tails was 64.41 ÷ 65.92%. Losses of valuable metals with common tails are close to the level of the prototype,%: 12.60 ÷ 12.86 nickel; 1.50 ÷ 1.54 copper. Extraction of sulfur in the tailings amounted to 50.28 ÷ 50.98%, which is 4.99 ÷ 5.69% higher than in the prototype method.

Example 6 (experiment 14 of the table) - the proposed method.

The initial nutrition, scheme and conditions for the separation of copper-nickel pyrrhotite-containing ore are the same as in example 2. The difference is that a solution containing sodium bisulfite and amidosulfonic acid was used as a modifying reagent containing sulfur in the sulfoxide complex. When conditioning the intermediate flotation products, the mass ratio of sulfide ions to the chemical group SO ₃ H contained in the composition of bisulfite and amidosulfonic acid was maintained at 1: 7.5, and the pH value at the final stage of conditioning was 7.1 units.

The results of the experiment are shown in the table. The result obtained is significantly higher than the indicators achieved in experiments 2 and 11, carried out under conditions of separate use of sodium bisulfite and amidosulfonic acid. This result is even more superior to the indicators obtained by the prototype method (experiment 1). The metal content in selective concentrates was,%: in nickel - 12.10 nickel and 3.95 copper; in copper concentrate - 0.65 nickel and 29.65 copper. Metal recovery achieved,%: in nickel concentrate - 80.59 nickels and 17.58 copper; 2.63 nickels and 80.25 copper in a copper concentrate. The yield of total tails was 66.32%. Losses of valuable metals with common tails are close to the level of the prototype,%: 12.60 nickel; 1.52 copper. The recovery of sulfur in the tailings amounted to 52.30%, which is 7.01% higher than in the prototype method.

Example 7 (experiment 15 of the table) - the proposed method.

The initial nutrition, scheme and conditions for the separation of copper-nickel pyrrhotite-containing ore are the same as in example 6. The difference was that in this experiment, selective copper and nickel concentrates were obtained with a decrease in yield in order to improve their quality. In this case, the target extraction of non-ferrous metals was sought to be kept at the level of the prototype method (experiment 1). When conditioning the intermediate flotation products, the mass ratio of sulfide ions to the chemical group SO ₃ H contained in the composition of bisulfite and amidosulfonic acid was maintained at 1: 7.5, and the pH value at the final stage of conditioning was 7.1 units. This example is given to ensure comparability of the proposed method and the prototype method for the targeted extraction of nickel and copper in the same selective nickel and copper concentrates.

The results of the experiment are shown in the table. Received high-quality nickel and copper concentrates. The yield of selective nickel concentrate was 12.73% with a content of 15.07% nickel, which is much better than in the prototype - 20.38% and 9.21%, respectively. The extraction of Nickel in Nickel concentrate amounted to 73.50%, which is even slightly higher than in the prototype (71.64%). The resulting selective copper concentrate contained 0.51% nickel and 30.10% copper. With such a high quality of copper concentrate, far superior to the quality of the concentrate obtained in the prototype method (1.52% nickel and 28.17% copper), the target copper recovery was approximately preserved at the base level - 76.79% against 76.81% for prototype. The yield of total tails was 65.44%. Losses of valuable metals with common tails are close to the level of the prototype,%: 12.59 nickel; 1.53 copper. Extraction of sulfur in the tailings amounted to 51.60%, which is 6.31% higher than in the prototype method.

The table shows examples that differ in the conditioning conditions of the intermediate flotation products: by the mass ratio of the sulfide-containing and sulfoxide-modifying reagents used and the pH value at the final conditioning stage, as well as by the type of products used to prepare the modifying reagent containing sulfide sulfur, and reagents- modifiers containing the chemical group SO ₃ H.

According to the obtained experimental results (experiments 2 ÷ 4 and 7 ÷ 15), the proposed method of flotation separation of sulfide copper-nickel pyrrhotite-containing ores provides higher quality selective copper and nickel concentrates than in the prototype method, while increasing the completeness of the target extraction in them nickel and copper. This is achieved due to a deeper withdrawal of pyrrhotite to the flotation tailings (as can be seen from the level of sulfur extraction into the tailings), without increasing the loss of non-ferrous metals. This factor is of paramount importance, since it simultaneously improves both environmental and technical and economic indicators of concentrate processing at pyrometallurgical processes, which is reflected in a reduction of environmentally harmful emissions of sulfur dioxide and the loss of valuable components with dump iron slags.

A comparison of the result obtained in experiment 2 with the result of experiment 1 (prototype) shows that under conditions comparable in terms of losses of non-ferrous metals with dump flotation tailings (nickel 12.72 ÷ 12.89%; copper 1.58 ÷ 1.59 %), the quality of the resulting selective concentrates in the proposed method is significantly higher than in the prototype method. The nickel content in nickel concentrate is 1.1% higher; copper in copper concentrate - by 1.05 abs.%. At the same time, the copper concentrate contains 2.14 times less nickel (0.71% versus 1.52%), which is very important for the processing of the concentrate in the pyrometallurgical cycle: the formation of recycled nickel slag and, accordingly, the operating costs for its processing are reduced. The level of target extraction of non-ferrous metals into the concentrates of the same name is significantly higher: nickel to nickel concentrate - by 8.55 abs.%; copper to copper concentrate - by 3.75 abs.%. The output of sulfur in the tailings of flotation in the proposed method is higher by 5.0 abs.%, Which will reduce the cost of sulfur utilization during oxidative smelting of concentrates in the metallurgical industry.

A comparison of the results obtained in experiment 2 with the results of experiments 7 ÷ 9 shows that the efficiency of ore separation in the proposed method does not depend on the type of modifier reagent used, containing sulfur in the form of a sulfide ion. In particular, when using both sodium sulfide (experiment 2) and polysulfides of sodium and calcium in the composition of products — sulfur liquor (experiment 7); calcareous broth (experiment 8); polysulfide-thiosulfate reagent obtained on the basis of belite (nepheline) sludge (experiment 9) - nickel concentrates containing 10.13 ÷ 10.36% nickel were obtained when it was extracted into a concentrate 79.60 ÷ 80.19%. Copper concentrates contained 0.69 ÷ 0.73% nickel and 29.02 ÷ 29.22% copper. The extraction of copper in copper concentrate amounted to 79.92 ÷ 80.69%. The obtained indicators significantly exceed the indicators obtained by the prototype method (experiment 1). Nickel concentrates contained 0.92 ÷ 1.15 abs.% More nickel while extracting nickel in nickel concentrates 7.96 ÷ 8.32 abs.% Higher. Copper concentrates contained nickel 0.79 ÷ 0.83 abs.% Less with a higher copper content - 0.85 ÷ 0.91 abs.%. The increase in copper extraction in copper concentrate compared to the prototype was 3.11 ÷ 3.88 abs.% Sulfur recovery in tailings increased by 4.77 ÷ 5.02 abs.%. It should be noted that the use of belitic sludge as an alkaline reagent, which is a large-tonnage waste from alumina production, can simultaneously solve a serious environmental problem. Currently, this industrial waste has not yet been found to have an adequate disposal method for the volume of its formation. Sludge fields, which occupy significant areas in the territory adjacent to alumina refineries, cause significant damage to the natural environment.

The results of experiments 10 ÷ 13 in comparison with the results of experiment 2 show that the efficiency of ore separation in the proposed method does not depend on the type of modifier reagent used, which contains the chemical group SO ₃ H. In experiment 10, carried out using a modifier reagent on based on an inorganic compound — calcium bisulfite, as in experiments 11–13, in which organic compounds — water-soluble sulfonic acids (amidosulfonic acid, a mixture of alkylarylsulfonic acids, ethanesulfonic acid ce cellulose), results close to those of experiment 2 were obtained. Nickel concentrates in experiments 10–13 contained 10.18–10.38% nickel when extracted into concentrate 79.32–80.34%. The metal content in the obtained copper concentrates is: 0.69 ÷ 0.72% nickel and 28.77 ÷ 29.24% copper. The extraction of copper in copper concentrate amounted to 79.04 ÷ 80.04%. The total tailings yield amounted to 64.41 ÷ 65.92% when sulfur was extracted in them - 50.28 ÷ 50.98%. With total flotation tails, the following was lost: 12.60 ÷ 12.86% nickel and 1.50 ÷ 1.59% copper, which does not exceed the level of metal loss in the prototype method (12.89% nickel and 1.59% copper) . The results obtained in the experiments 10 ÷ 13 are significantly higher than the results obtained by the prototype method (experiment 1). Nickel concentrates contained 0.97 ÷ 1.17 abs.% More nickel while extracting nickel in nickel concentrates 7.68 ÷ 8.70 abs.% Higher. Copper concentrates contained nickel 0.80–0.83 abs.% Less with a higher copper content — 0.60 ÷ 1.07 abs.%. The increase in copper extraction in copper concentrate compared to the prototype was 2.23 ÷ 3.23 abs.%. Extraction of sulfur in tailings increased by 4.99 ÷ 5.69 abs.%.

When the values of the parameters of post-air conditioning of intermediate flotation products with sulfur-containing modifying reagents exceed the stated range, the main indicators of flotation ore separation sharply worsen, approaching the results obtained by the prototype method.

In particular, in experiment 5, which was characterized by extremely low parameters of post-radial conditioning (the mass ratio of sulfide sulfur of one modifier reagent to the SO ₃ H chemical group of another modifier reagent was 1: 14.7; pH = 5.8 units), was obtained nickel concentrate containing 9.45% nickel. Moreover, the extraction of Nickel in Nickel concentrate amounted to 74.77%. Copper concentrate was characterized by a high nickel content of 1.23%, and copper extraction into it was only 78.13%. 47.00% of sulfur was recovered in the tailings with a yield of 61.98%. These indicators are comparable with the results of ore separation obtained by the prototype method (experiment 1).

With extremely high parameters of post-radial conditioning (the mass ratio of sulfide sulfur of one modifier reagent to the SO ₃ H chemical group of another modifier reagent is 1: 0.4; pH = 8.3 units), the enrichment values obtained (experiment 6) are practically the same , as in the prototype method (experiment 1). The nickel content in the Nickel concentrate is 9.62%, with the recovery of 73.16%. The copper concentrate contained an increased percentage of nickel - 1.41%, and the extraction of copper into it was 75.31%. Yield of tailings - 61.98%; sulfur recovery in them - 46.51%.

In experiment 14, when conditioning flotation intermediates, a solution containing sodium bisulfite and amidosulfonic acid was used as a modifying reagent containing sulfur in the sulfoxide complex. Higher results were achieved than in experiments with the separate use of sodium bisulfite (experiment 2) and amidosulfonic acid (experiment 11). A nickel concentrate containing 12.10% nickel was obtained with an extraction of 80.59%. The metal content in the resulting copper concentrate was: 0.65% nickel and 29.65% copper. Extraction of copper in copper concentrate - 80.25%. The yield of total tails was 66.32% with the extraction of sulfur in them - 52.30%. With total flotation tails, 12.60% nickel and 1.52% copper were lost, which is comparable to the level of metal loss in the prototype method. The results obtained in experiment 14 are significantly higher than the results obtained by the prototype method (experiment 1). Nickel concentrate contained 2.89 abs.% More nickel with a higher recovery - 8.95 abs.%. The copper concentrate contained nickel 0.87 abs.% Less with a higher copper content - 1.48 abs.%. The increase in the extraction of copper in copper concentrate compared to the prototype amounted to 3.44 abs.%. The extraction of sulfur in the tailings increased by 7.01 abs.%.

In experiment 15, the flotation separation of ore was carried out in such a way as to achieve the highest possible quality of copper and nickel concentrates while maintaining approximately the same level as the prototype method (experiment 1) of the target extraction of non-ferrous metals into concentrates. This experience most convincingly illustrates the advantages of the proposed method - the possibility of significantly improving the quality of the target concentrates and reducing their physical mass without increasing the loss of valuable components with waste enrichment products. The nickel content in the Nickel concentrate was 15.07%, which is 5.86 abs.% Higher than in the prototype method (9.21%). Moreover, the extraction of Nickel in Nickel concentrate remained no lower (73.50%) than in the prototype - 71.64%. The resulting copper concentrate contained 0.51% nickel and 30.10% copper. These indicators are significantly higher than in the prototype method - 1.52% and 28.17%, respectively. The extraction of copper in copper concentrate amounted to 76.79% (in the prototype - 76.81%). The increase in sulfur recovery in tailings in comparison with the prototype amounted to 6.31 abs.%.

In general, an analysis of the results shows that, with the optimal value of the post-air conditioning parameters of intermediate flotation products with sulfur-containing modifying reagents (experiments 2 and 14), the use of the proposed method allows to achieve significantly higher ore separation indicators compared to the prototype method (experiment 1):

- allows you to increase the Nickel content in Nickel concentrate from 9.21 to 10.31 ÷ 12.10% while increasing the completeness of the extraction of Nickel in Nickel concentrate from 71.64 to 80.19 ÷ 80.59%;

- in the obtained copper concentrates, the mass fraction of nickel decreases from 1.52 to 0.65 ÷ 0.71%, while the copper content increases from 28.17 to 29.22 ÷ 29.66%. The extraction of copper in copper concentrate in this case increases from 76.81 to 80.25 ÷ 80.56%;

- at the same time, without increasing the loss of valuable components, the sulfur recovery in the dump flotation tailings increases from 45.29 to 50.29 ÷ 52.30%.

This mode of ore separation is preferable at the same time both to improve the ecology of the subsequent processing of selective nickel and copper concentrates, and to improve the technical and economic indicators of the production of non-ferrous metals.

If necessary, the method allows to achieve significantly higher quality selective Nickel and copper concentrates (experiment 15) compared with the prototype (experiment 1) while maintaining the basic completeness of the target extraction of non-ferrous metals in concentrates and the deep output of pyrrhotite sulfur in the tailings. In particular, upon extraction of nickel in nickel concentrate at the level of 73.50%, and copper in copper - 76.79%, the nickel content in nickel concentrate in the proposed method increases from 9.21 to 15.07%, and the copper content in copper concentrate - from 28.17 to 30.10%. The nickel content in the copper concentrate decreases from 1.52 to 0.51%, i.e. ~ 3 times, and the level of sulfur recovery in the dump flotation tailings increases from 45.29 to 51.60%.

The main advantages of the proposed method include the ability to simultaneously solve several pressing problems:

- increasing the complexity of processing unique sulfide copper-nickel pyrrhotite-containing ores;

- reduction of investment costs and operating costs in the field of metallurgical production due to the receipt of higher-quality concentrates in processing;

- reduction of man-caused environmental impact due to a deeper removal of sulfur into dump tailings, which ensures reduction of sulfur dioxide emissions and slag output in the pyrometallurgical production cycle;

- involvement in the production of the dump product of alumina production - belitic sludge, which plays the role of an alkaline reagent for the production of sulfide-containing reagent - modifier;

- partial utilization of sulfur dioxide, including from poor metallurgical gases, through the use of sulfur dioxide and trioxide for the production of sulfoxide modifying reagent: bisulfite and sulfonic acid.

Claims (5)

1. The method of flotation separation of sulfide copper-nickel pyrrhotite-containing ores, including grinding ore, collective flotation in the presence of sulfhydryl collectors to obtain a collective copper-nickel concentrate, nickel-pyrrhotite product and tailings, regrinding of collective copper-nickel concentrate, post-air conditioning of intermediate products with sulfur-containing modifying reagents, one of which contains sulfur in sulfide form, and the other as a part of sulfox of the complex, intermediate aeration of the pulp and subsequent separation of copper minerals by flotation in the presence of a sulfhydryl collector into a selective copper concentrate, flotation separation of the nickel-pyrrhotite product in the presence of a medium control reagent, sulfhydryl collector and pyrrhotite-depressant reagent to obtain selective nickel concentrate and nickel-containing pyrrhotite characterized in that as a modifying reagent containing sulfur in the sulfoxide complex, and polzujut water-soluble inorganic and / or organic compounds containing in their structure chemical group SO ₃ H, wherein the weight ratio of sulfide sulfur reagent modifier to a chemical group SO ₃ H modifier other reactant is 1: (0,5-14,5 ), and the pH value at the final stage of conditioning is maintained in the range of 5.9-8.2 units. 2. The method according to claim 1, characterized in that as the modifying reagent containing sulfur in sulfide form, polysulfides of alkali and / or alkaline earth metals are used. 3. The method according to claim 1, characterized in that as an inorganic compound containing the chemical group SO ₃ H in its composition, alkali and / or alkaline earth metal bisulfites are used. 4. The method according to claim 1, characterized in that as an organic compound containing the chemical group SO ₃ H in its composition, water-soluble sulfonic acids are used. 5. The method according to claim 2, characterized in that the polysulfides of alkali and / or alkaline earth metals are used in the composition of polysulfide-thiosulfate solutions obtained by the interaction of sulfides of alkali and / or alkaline-earth metals, as well as their oxides, hydroxides and complex alkaline salts with elemental sulfur.