RU2441080C1 - Method of producing copper matte - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: burden is loaded into shaft furnace that comprises copper-containing stock and fuel containing coke. Note here that said coke is produced by carbonising the burden containing 5 to 100% of product, the yield of volatile substances making some 14-25%, obtained by delayed low-temperature carbonisation of heavy oil residues. Then, burden is subjected to oxidising fusion.

EFFECT: reduced fuel consumption higher smelting rate of copper-containing stock, reduced copper content in slug.

3 tbl

Description

The invention relates to a method for processing sulfide copper ores, concentrates and other copper-containing materials in shaft furnaces in order to obtain matte.

The production of copper matte occurs in the process of processing sulfide copper-containing raw materials, as a rule, in the process of its oxidative mine smelting (V.I.Smirnov, A.A. Tseidler, I.F. Khudyakov, A.I. Tikhonov "Metallurgy of copper, nickel and cobalt ", - M., 1966,:" Metallurgy ", vol. I, pp. 146-147). At the same time, coke is used as fuel, the consumption of which is 10% or more of the charge weight. Sulfides in this type of melting are subjected to the oxidative action of oxygen in the solid or molten state.

The disadvantage of this method is the increased consumption of coke and the increased removal of copper with slag (high copper content in the slag).

For the prototype, a method was selected for producing copper matte during oxidative melting of a charge, including copper-containing raw materials and fuel - coke (V.I. Smirnov, A.A. Tseidler, I.F. Khudyakov, A.I. Tikhonov "Metallurgy of copper, nickel and cobalt ", - M., 1966,:" Metallurgy ", vol. I, pp. 45-47, 168-169).

The disadvantage of this method is the increased consumption of coke and increased removal of copper with slag (increased copper content in the slag).

The technical result is to reduce fuel consumption and increase the melt of copper-containing raw materials by increasing the calorific value and reducing the reactivity of coke, reducing the copper content in slag due to the interaction of coke having a high sulfur content with copper from the melt and converting it to sulfur sulfide, which is converted to matte.

The technical result is achieved due to the fact that in the method for producing copper matte, which includes loading into a shaft furnace a charge containing initial copper-containing raw materials and fuel, which includes coke; subsequent oxidative melting of the charge, according to the invention, coke is used as fuel, which is the result of coking of a charge containing a product with a yield of volatiles from 14 to 25% in the amount of (5-100) wt.%, obtained by delayed semicoking of heavy oil residues.

When carrying out oxidative melting, high-quality coke with low reactivity is required, since during oxidative smelting, oxygen is present in the entire volume of the furnace. Those. there is a 100% excess of air and when using highly reactive coke, combustion will spread to the entire volume of the furnace, and so-called “goats” will form in the furnace.

Coke obtained during the coking of petroleum coke with a yield of volatile substances from 14 to 25% enriched in the process of delayed coking with high molecular weight volatile substances (charge 6 Table 1) differs from petroleum coke obtained by calcining petroleum coke with a yield of volatiles of 8-10% (up to 14%), for example, in ring or rotary drum furnaces, higher strength, increased coarseness of pieces of coke (D, mm), reduced reactivity (CRI), increased post-reaction strength (CSR). Thus, it is a special coke with improved properties. Additives of such a semi-coke to coal blends (charge 1-5 Table 1) improve the quality of the obtained coke.

Coke obtained from a mixture containing a product (obtained by delayed semi-coking of heavy oil residues) with a yield of volatiles from 14 to 25% in an amount of (5-100) wt.%, Has the properties shown in table 1.

For convenience of presentation, the product with a yield of volatiles from 14 to 25%, obtained by the method of delayed semi-coking of heavy oil residues, hereinafter referred to as additive DC.

The coal part of the charge is given as one of the special cases for example. Other components and combinations of charges are possible.

At the same time, Table 1 shows examples of blends that are designated as blends 1,2,3,4,5,6 and coke quality indicators from these blends.

Example 7: The mixture 7 is composed of 50 percent of petroleum coke with a yield of volatiles of 14.2% and 50% of petroleum coke with a yield of volatiles of 24.8%, while coke was obtained with CSR = 70.5%, CRI = 23, 8%. When testing in the heat obtained results similar to the results according to example 6.

The indicator W ^r _t is an indicator of the mass fraction of total moisture. A ^d - coke ash in the dry state; V ^daf is the yield of volatile substances in the dry ashless state of coke; S ^d - sulfur content in the dry state of coke; CRI - an indicator of the reactivity of coke; CSR is an indicator of the post-reaction strength of coke.

Tests, the results of which are shown in table 1 and table 2, were carried out on a Nikolaev furnace, show that the post-reaction strength of coke from a charge with DC added is higher than that of coke without an additive. The dependence of coke CSR on the content of the additive in the charge is close to the logarithmic: logCSR = A + BlgC, where C is the content of the DC additive in the charge.

Melting using coke with the addition of DC should be accompanied by maintaining the previously used loading conditions (spike size) with more complete combustion (using chemical potential) due to the reduction in spike height, lowering the surface of pieces of coke, and increasing gas permeability.

The proposed method was tested in semi-pyrite (oxidative) mine smelting of sulfide copper ores, concentrates and copper-containing materials on an industrial shaft furnace, having the following characteristics:

length of the furnace, mm - 11400;

height (from the foundation to the top), mm - 6000;

sectional area in the tuyere plane, m ² - 15.5;

the number of tuyeres, pcs. - 73;

the method of loading the charge components into a shaft furnace is mechanized, one-sided, with the help of trolleys through windows closed by shutters;

air blast consumption, thousand n.m ³ / hour - 20-40;

oxygen consumption for enrichment of the blast, thousand nm ³ / hour - up to 2;

fuel consumption, kg / t solid charge - 90-130;

the volume of the front hearth, m ³ - 90.

Smelting products from a shaft furnace with a temperature of 1200-1300 ° C are uniformly discharged into the front furnace and mechanically separated (by density) by settling on slag and matte. Slag is produced continuously by gravity through a cast-iron chute into a stream of water with the formation of fine (up to 6 mm) granulate. Matte is released through the siphon periodically as it accumulates.

The tests were carried out on the same (same) copper-containing charge on one furnace according to the claimed method (examples 1-5) and according to the method of the prototype. In the prototype, coal-fired metallurgical coke larger than 40 mm was used as a reducing fuel.

According to the proposed method (examples 1-5) was used coke from a coal charge and additives coking DC, the quality of which is shown in table 1.

The composition of the components of the charge according to the examples presented in Table 2:

table 2 The composition of the solid charge according to the prototype The composition of the solid charge by the proposed method Example 1 Metallurgical coke Coke from coal charge with the addition of DC in the amount of 5% A mixture of copper-containing materials A mixture of copper-containing materials Fluxes (reverse converter slag) Fluxes (Reverse Converter Slag) Example 2 Coke from coal charge with the addition of DC in the amount of 10% A mixture of copper-containing materials Fluxes (reverse converter slag) Example 3 Coke from coal charge with the addition of DC in the amount of 30% A mixture of copper-containing materials Fluxes (reverse converter slag) Example 4 Coke from coal charge with the addition of DC in the amount of 50% A mixture of copper-containing materials Fluxes (reverse converter slag) Example 5 Coke from coal charge with the addition of DC in the amount of 100% A mixture of copper-containing materials Fluxes (reverse converter slag)

As a copper-containing material for oxidative semi-pyrite smelting in a shaft furnace according to the existing technology (prototype) and according to the claimed method (examples 1-5 table 2) were used: "cake" from an average mixture of copper-containing materials (fine fractions of ore, concentrates, clinker, small scrap , small copper wastes, precious metals containing copper); large fractions of waste secondary copper-containing raw materials (scrap, shavings, scraps); lump copper ore.

Mixing and averaging the components of the "pie" was carried out using excavators and a bulldozer. The copper content in the pie is 12.5%.

The flux used was limestone and reverse converter slag, which also allows melt temperature to be controlled.

The loading of components into shaft furnaces was carried out according to the technological instruction through the loading windows with “ears in the following order:

- coke;

- copper-containing secondary raw materials;

- “pie”, including small fractions of ore;

- flux (limestone);

- large fractions of lump copper-bearing ore;

- flux (reverse converter slag).

The components were loaded according to the instructions with an interval of (30 ± 5) min.

The composition of the charge,%:

“Pie” - (50-60);

- copper-containing secondary raw materials - (5-10);

- large fractions of lump copper-bearing ore - (10-15);

- flux (reverse converter slag) - (20-40)

- flux (limestone) - (5-10).

The consumption of oxygen-enriched up to 24% of air blast was 38-43 thousand nm ³ / hour. The excess blast was 100%, while the combustion of carbon coke in the focus of the furnace occurs to CO ₂ : C + O ₂ = CO ₂ .

At the same time, due to an excess of oxygen, oxidative reactions occur both in the focus of the furnace and in the preparation zone. Therefore, for such smelting, lumpy low-reaction coke is required.

,In the preparatory zone, oxidation reactions of iron sulfides are carried out according to the reaction:

,

.and iron oxides in the focus of the furnace in the presence of silica bind to silicates and, when settled, pass into slag:

.

According to the physicochemical conditions of the smelting, complete decomposition of magnetite contained in the ore and concentrates does not occur, part of it passes into the smelting products.

Hot furnace gases passing through the charge layer carry out its thermal preparation and oxidation of its individual components.

Sulfides of copper, after a series of transformations, in the form of semi-sulfur copper pass into matte. Nickel sulfides simple and complex also turn into matte.

Obtained during melting, the molten mass leaves through the center hole of the furnace with a temperature of 1200-1300 ° C in the front furnace of the furnace.

In the front furnace, a mechanical separation of the molten mass into matte and slag occurs due to the difference in their specific gravity.

Slag is continuously produced and granulated by a stream of water.

The chemical composition of the slag according to the results of the smelting according to the claimed method was as follows,%:

SiO ₂ FeO Cao Al ₂ O ₃ Cu 32-38 15-20 6-12 10-15 up to 0.3

Matte is issued periodically in the presence of matte in the furnace.

Previously, according to the statistical data of the inventors, it was found that the coke consumption is larger than 40 mm when melting copper-containing materials is 15% lower compared to the coke consumption larger than 25 mm. Therefore, the consumption of larger coke, ceteris paribus, should be reduced.

The authors conducted tests and determined the indices of oxidative melting of copper-containing materials according to the claimed method with coke from the charge with the content of the additive DC in the amount of from 5 to 100 wt.%.

Carried out several stages (periods) of industrial swimming trunks using coke as fuel according to the claimed method with different participatory participation. In the base period, only coal-mining metallurgical coke larger than 40 mm was used.

The results of the tests conducted by the authors are shown in table 3.

Conducted by the authors of the present invention, industrial oxidative melting of copper-containing materials with the replacement of part of metallurgical coke with special coke with DC in the amount of from 5 to 100 wt.% Showed the possibility of reducing coke consumption during the melting of copper-containing materials, showed that when using DC additive copper losses are reduced (decreases copper content in the slag).

In addition, due to the reduction of coke ash and, therefore, the reduction of fluxes for slagging of coke ash, the amount of slag and copper loss with this part of non-formed slag are also reduced.

The results of the tests showed that when a part of metallurgical coke is replaced with special coke from a charge with DC added, there is a reduction in coke consumption and an increase in melt compared to metallurgical coke.

Reducing the consumption of coke obtained from coal-containing blends with the addition of DC, for two reasons. Firstly, coke with the addition of DC is lower in ash content, and secondly, the fineness of coke pieces is higher. Ash content is given in table 1. An industrial verification of the production of coke from a charge with a content of DC in the amount of 5 to 100 wt.% Showed that the average size of pieces of such coke with a content of DC in the amount of 40% is 90 mm. The average size of metallurgical coke is 55-65 mm.

In addition, coke with the addition of DC has a higher density - 1.25 g / cm ³ , versus 1.00 g / cm ³ for coke without the addition of DC, as well as a higher true density of 1.830-1.840 g / cm ³ against 1.790-1.815 g / cm ³ for coke from the mixture without the addition of DC.

The consumption of large coke is always lower at the same temperature conditions and rational loading technology due to a more complete combustion of carbon coke (full use of the chemical potential, i.e., afterburning of CO). At the same time, environmental conditions are improved by reducing fuel consumption and its more complete chemical combustion (reduction of CO emissions). The high sulfur content of coke is used in smelting to produce matte.

It should also be noted that with the increase in the content of DC additives in the charge, the cost of coke decreases, therefore, the process of production of copper matte is cheaper.

Claims (1)

A method of producing copper matte, comprising loading a charge containing copper-containing raw materials and fuel containing coke into a shaft furnace and subsequent oxidative smelting of the charge, characterized in that coke obtained by coking a charge containing 5-100 wt.% Is used as coke product with a yield of volatiles from 14 to 25%, obtained by delayed semi-coking of heavy oil residues.