RU2156315C1 - Method of processing of nickel-containing copper slags - Google Patents

Abstract

FIELD: metallurgy of heavy nonferrous metals. SUBSTANCE: method includes crushing, grinding, magnetic separation resulting in obtaining of magnetic and nonmagnetic products, classification of nonmagnetic product into fractions, and their further processing. Obtained magnetic product is subjected to two-stage leach with producing at the first stage of nickel-cobalt solutions and nonsoluble residue which is subjected to secondary leaching together with nonmagnetic product of 6 mm fraction with intensive aeration to produce copper solution. Leaching is conducted with solutions containing free sulfonating acid at pH on not in excess of 3.5 and solution temperature of 50-80 C. Aeration is effected with air flow rate of 5-8 ncu.m/h for 1 ncu.m of solution. EFFECT: provided selective separation of copper from nickel, cobalt and iron, and produced nickel-cobalt and copper solution for hydrometallurgy of nickel and cobalt and copper. 2 cl, 2 dwg 1 tbl, 4 ex

Description

 The invention relates to the field of metallurgy of heavy non-ferrous metals, in particular to the processing of rolled copper nickel-containing slag.

 Rolled slag is formed when converting copper nickel-containing matte during the cooking of blister copper.

 A known method of processing dry copper nickel-containing converter slag (Mechev V.V., Converting nickel-containing copper matte - M.: Metallurgy, 1973, p. 9), including melting the slag together with copper-nickel matte in the process of converting it to copper-nickel matte. According to this method, copper, nickel and cobalt are extracted from copper slag into matte as a result of sulfidation, and iron is converted into converter slags.

 The known method does not solve the problem of separating copper from nickel and cobalt for the purpose of their separate processing in the copper and nickel branches of production and leads to a deterioration in the quality of matte matte due to the increase in their copper content. In addition, the method is characterized by low rates of cobalt extraction, high operating costs, process variability and the return of a large amount of copper, nickel and cobalt for recycling to nickel and copper concentrates.

 A known method of processing rolled copper nickel-containing converter slag (Sukharev S.V., Knyazev M.V. M.V., Alterman L.S. Rinsing dry rolled slag with rich copper nickel-containing matte at NMMC, Non-ferrous metals, 1989, N 1, c . 47), which includes melting slag together with copper nickel-containing matte in the process of converting it to blister copper. As a result of sulfidation, a part of copper is extracted from copper slag into nickel-containing copper matte, and its other part, as well as nickel, cobalt and iron, are converted to copper converter slags.

 The known method only partially solves the problem of separating copper from nickel and cobalt for the purpose of their separate processing in the copper and nickel branches of production. The method is characterized by low rates for the extraction of Nickel and cobalt, multifrequency scheme, significant costs for the processing of slag.

 The closest in technical essence to the proposed method is a method for separate processing of rolled copper nickel-containing slag (Yezhov E.I., Ogorodnikova L.A., Sirkis A.L., Zheldybin O.I., Emelina L.N. Development and implementation of resource-saving processes in nickel-cobalt production, collection of scientific works, Gipronickel, Leningrad, 1988, p. 62), including large and medium crushing, grinding, magnetic separation, obtaining magnetic and non-magnetic products, the extraction of copper into a non-magnetic product, and nickel, cobalt and iron in ma netic product classification by size nonmagnetic slag fraction, a major portion of melting (fraction 6 mm) and shallow parts (fraction -6 mm) after pelletizing for the blister copper to copper matte and the melting magnetic product after pelletizing with a copper-nickel matte.

 The disadvantages of this method include the low extraction of cobalt and nickel, the multi-band design and high processing costs, a significant amount of return of nickel, cobalt and copper with a magnetic fraction to copper-nickel matte for recycling.

 Our proposed method solves the following technical problem; increasing the extraction of non-ferrous metals, the selective separation of copper from nickel and cobalt, obtaining nickel-cobalt solutions for copper electroextraction, reducing the cost of processing copper slag, simplifying the technological scheme.

 In the production of copper from copper sulfide concentrates from the flotation separation of copper-nickel matte, copper-containing nickel slags are formed when converting copper mattes or sulphurous copper (with a sulfur content of 1.5 - 3%) to blister copper. Copper slags contain,%: nickel 12 - 18, copper 31 - 36, cobalt 0.16 - 0.2, iron 16 - 25 (or 0.5 - 2.0% when converting copper sulfide with a sulfur content of 1.5 - 3.5%). The mass of slag from blister copper is up to 30%.

 A method for separate processing of slag, developed as a prototype, involves the preparation of three components: non-magnetic product fraction + 6 mm, non-magnetic product fraction 0-6 mm and a magnetic product fraction -2 mm The distribution of copper in these products, respectively: up to 8%; 40 - 70%; 22 - 52% ;. The distribution of metals is affected by the inhomogeneous composition of the slag, its cooling rate, the particle size of the slag after grinding, the operating parameters of the conversion technology.

 Copper in the slag 78 - 85% is in the form of metal splices - "kings" and 14 - 20% in the form of oxide compounds associated with oxides of nickel, iron and cobalt, and 0.5 - 2.0% in the form of sulfide compounds.

Nickel, cobalt and iron in the slag are 95 - 98% in the form of complex oxide formations. The content of sulfide minerals in the slag is not more than 2%, the amount of slag-forming oxides SiO ₂ , Al ₂ O ₃ , CaO and MgO usually does not exceed 6%.

 In the non-magnetic part of the slag, copper is predominantly in the form of metal splices - "kings". A large non-magnetic part of the slag fraction +6 mm in chemical composition approximation to black copper. In the non-magnetic part of the slag fraction of 0 - 6 mm Nickel contains up to 10%.

 In the magnetic part of the slag, copper is in two forms: metal, not less than 70% and oxide, up to 30% and sulfide, not more than 0.5 - 2.0%. Nickel, cobalt, iron in the form of oxide compounds, soluble and insoluble in sulfuric acid.

Our proposed method for processing copper nickel-containing slag includes crushing, grinding, magnetic separation, obtaining magnetic and non-magnetic products, classifying the non-magnetic product into fractions and their further processing, characterized in that the magnetic product is subjected to two-stage leaching to obtain nickel-cobalt solutions in the first stage and insoluble residue, which is subjected to secondary leaching together with a non-magnetic product fraction -6 mm with intensive aeration with obtaining By copper solutions, leaching is carried out with solutions containing free sulfuric acid at a pH of not more than 3.5 and a solution temperature of 50 - 80 ^o C. Aeration is carried out at an air flow rate of 5 - 8 nm ³ / h at 1 nm ³ .

The rational temperature of the leaching process determines the temperature range of 50 - 80 ^o C, which at the upper limit provides satisfactory wear of the reactor in an acidic environment, limits the evaporation of solutions and the formation of aerosols. Lowering the temperature below 50 ^o C causes a slowdown in the leaching process, both soluble in sulfuric acid compounds of Nickel, cobalt and iron, and copper during aeration of the solution with air.

 The acidity of the leaching process should be no more than 3.5, because with a decrease in acidity, the formation of suspensions of nickel hydroxide and iron, which are poorly filtered.

The process is as follows. Leaching of magnetic and non-magnetic products of the -6 mm fraction is carried out in a heated reactor, under an atmosphere of pressure and working exhaust ventilation, with constant stirring of the pulp. The sulfuric acid solution containing free sulfuric acid is pumped into the reactor, heated to 50 - 80 ^o C, the stirrer is turned on and the magnetic slag fraction is charged in an amount sufficient to neutralize sulfuric acid based on the translation of 30 - 45% nickel, cobalt, iron and 20 - 35% copper and the completion of the process at a pH of not more than 3.5. The selectivity of the separation of nickel, cobalt and iron from copper contained in the magnetic product is ensured by the fact that acid-soluble oxide compounds of nickel, cobalt, and iron pass into the solution. Copper, which is in the magnetic product at 85 - 95% in the form of a metal phase, is dissolved in the absence of oxidizing agent (aeration). The end of the leaching process of a magnetic product is determined by the decrease in the response rate of sulfuric acid, measured in grams per liter of solution per unit time, which at the end of leaching decreases by 8 - 10 times compared with the start of leaching.

 The resulting nickel-cobalt solution is filtered and decontaminated by known methods, for example, by extraction or electroextraction of copper with an insoluble anode or by cementation with nickel powder. The purified nickel-cobalt solution with a copper content of up to 3 g / l is sent to the hydrometallurgical nickel production.

The insoluble residue obtained after the first stage of dissolution of the magnetic product, containing acid-insoluble compounds of nickel, cobalt and iron and metallic copper, is loaded together with the non-magnetic product of the -6 mm fraction into the next reactor to the second stage of dissolution. Previously, a sulfuric acid solution containing free sulfuric acid is poured into the reactor, the solution is heated to a temperature of 50 - 80 ^o C. The products are loaded with intensive aeration of the solution at an air flow rate of 5 - 8 nm ³ / h per nm ^{3 of} solution. During leaching, copper selectively passes into the solution. The process is carried out at a pH of not more than 3.5 with the transfer to a solution of 95 - 98% copper from the residue of the first leaching stage and from the non-magnetic slag product. The end of the process is controlled by reducing the response rate of sulfuric acid. The resulting copper solution with a copper content of 45 - 55 g / l and impurities of nickel, cobalt and iron in total no more than 5 g / l is sent to the hydrometallurgical copper production.

 The insoluble residue of the second leaching stage, containing mainly oxide compounds of nickel, cobalt and iron and, as an impurity, about 5% copper, is sent to the nickel refining plant for reduction (or after drying for smelting anodes for electrolytic nickel production).

 The proposed method provides the extraction of copper in solutions up to 95 - 98%. Nickel, cobalt, and iron are extracted 25–45% in nickel – cobalt solutions and 55–75% in the solid residue.

 Thus, the proposed method for processing copper nickel-containing slag provides selective separation of copper from nickel, cobalt and iron, as well as obtaining nickel-cobalt and copper solutions for hydrometallurgy of nickel and cobalt and copper.

 The method is worked out on a laboratory and semi-industrial scale.

 Examples of the method.

 Experience 1. Processed copper Nickel-containing slag, previously divided into magnetic (MP) and non-magnetic (NP) products in the ratio, wt.%: 80.5 and 19.5.

 The composition of the MP, wt.%: Nickel 13.9, copper 27.5 cobalt 0.8, iron 20.8. Grain size MP: 78% (-0.2 mm), 14% (0.2 - 1 mm), 8% (1 - 2 mm).

 The composition of the NP, wt.%: Nickel 4.2, copper 77.5, cobalt 0.3, iron 1.2. Grain size NP: 48% (-0.2 mm), 32% (0.2 - 1 mm), 20% (1 - 6 mm).

60 dm ^{3 of a} solution with a sulfuric acid content of 100 g / l were pumped into a reactor with a stirrer, heating, displacement of 80 dm ³ , heating was turned on and, after heating the solution to 75 ± 0.5 ^o C, a stirrer with a rotation speed of 55 r / min Then MP was loaded in the amount of 6 kg. After 3 hours, after a sharp slowdown and with a residual sulfuric acid content of 25 g / l, the process of the first stage of leaching of the MP was stopped, the solution was filtered, and the residue of leaching together with the NP was loaded into another reactor, which was previously filled and heated to 75 ± 0.5 ^o C solution with a sulfuric acid content of 80 g / l. The loading of the dissolution residue and NP into the second reactor was carried out with the stirrer switched on at a speed of 55 rpm and with intensive aeration of the solution with air in the amount of 6 nm ³ / h of air per 1 nm ^{3 of} solution. 3.5 hours after a sharp slowdown in acid response and with a residual acid content of 30 g / l, the process of the second leaching stage was stopped, the solution was separated from the insoluble residue by filtration.

The solution of the first leaching stage 55 dm ³ was poured into the third reactor with a stirrer and heating at a temperature of 75 ± 0.5 ^o C, nickel powder of 1.5 kg was loaded into it for decontamination, after 1.5 hours the deconvoluted solution was separated from the residue filtering.

Similarly, experiments were carried out with other parameters of the leaching process: at a temperature of 40, 50, 80 and 90 ^o C and air consumption for aeration in the second stage of leaching of 4, 5, 8 and 9 nm ³ / h per 1 nm ³ solution. As a result, it was found that the leaching rate in the temperature range of 50 - 80 ^o C is 25 - 40% higher than at a temperature of 40 ^o C. At a temperature of 90 ^o C, the solution evaporates intensively, 5 - 10% more intensively compared to the temperature range 50 - 80 ^o C. Accordingly, the proposed in the method the temperature range of the leaching process of 50 - 80 ^o C is optimal.

During air aeration, 4 nm ³ / h per 1 nm ^{3 of the} solution, the oxidation and leaching rates of copper decreased by 18 - 34 rel.% Compared with the aeration mode of 5 - 8 nm ³ / h per 1 nm ^{3 of the} solution, and during aeration, 9 nm ³ / h at 1 nm ^{3 of the} solution, foaming and spraying of the solution and particles of MP were observed with the formation of aerosols. Therefore, the mode of aeration of the solution with air, proposed in this invention, 5-8 nm ³ / h per 1 nm ^{3 of the} solution is optimal.

 The averaged experimental data for the interval of operational parameters declared in the proposed method are shown in FIG. 1, 2 and in the table.

 The kinetic characteristics of the extraction of nickel, cobalt, iron and copper into solutions of the first and second leaching stages confirm the possibility of preliminary dissolution and preparation of nickel-cobalt solutions in the first stage of dissolution of MP and copper solutions in the second stage of dissolution of MP and NP.

 These tables confirm the possibility of purification by known methods of decontamination of nickel-cobalt solutions of the first stage of dissolution of MP with obtaining solutions suitable for use in nickel hydrometallurgy.

 Thus, the experimental data indicate that the combination of the claimed features provides the processing of copper Nickel-containing slag in accordance with the proposed claims.

List of references
1. Mechev VV, Converting nickel-containing copper matte. - M.: Metallurgy, 1973, p. 9.

 2. Sukharev S.V., Knyazev M.V., Alterman L.S. - Washing of dry rolled slag with rich copper nickel-containing matte at NMMC, Non-ferrous metals, 1989, N 1, p. 47.

 3. Yezhov E.I., Ogorodnikova L.A., Sirkis A.L., Zheldybin O.I., Emelina L.N., Development and implementation of resource-saving technological processes in nickel-cobalt production, collection of articles. scientific labor. Gipronickel. - L., 1988, p. 62.

Claims (2)

1. A method for processing copper nickel-containing slag, including crushing, grinding, magnetic separation, obtaining magnetic and non-magnetic products, classifying the non-magnetic product into classes and their further processing, characterized in that the magnetic product is subjected to two-stage leaching with obtaining nickel-cobalt solutions in the first stage and insoluble residue, which is subjected to secondary leaching together with non-magnetic product fractions -6 mm with intensive aeration to obtain copper astvorov, leaching is carried out with solutions containing free sulfuric acid, at pH not exceeding 3.5 and a solution temperature of 50 - 80 ^o C. 2. The method according to claim 1, characterized in that aeration is carried out at an air flow rate of 5 - 8 nm ³ / h per 1 nm ³ solution.

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