RU2401873C1 - Procedure for processing oxidated nickel ore - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: processing procedure consists in supply of charge into slag melt in oxidising (melting) zone of two-zone furnace. Also charge contains source raw material and fluxes, liquid or solid processed slag, carbon containing material and oxygen containing blast supplied in quantities required for complete combustion of carbon and hydrogen with maximal heat release. Before supply of mixture of source raw material and fluxes into the oxidising (melting) zone of the furnace their mixture is preliminary roasted and supplied at temperature 500-1300°C. Melted charge forms slag melt coming into a furnace zone of reduction, whereto oxygen containing blast and carbon containing material are supplied. Notably, they are supplied at amount required for reduction of extracted material into a metal phase and for compensation of heat consumption by means of after-burning gases of the reduction zone above melt, whereupon melt products are tapped.

EFFECT: raised efficiency of melting process and reduced consumption of oxygen and carbon containing material.

3 cl, 4 tbl, 5 dwg, 2 ex

Description

The present invention relates to the field of non-ferrous metallurgy, in particular to a method for processing oxidized nickel ore containing non-ferrous metals and iron.

A known method (RF Patent No. 2323475, C22B 23/02, C22B 4/06) for the production of liquid metal in the processing of oxidized metal-containing natural raw materials and industrial materials. The method includes feeding a mixture consisting of feedstock, fluxes, liquid or solid processed slag, carbon-containing material and oxygen in an oxygen-containing blast in quantities necessary for complete combustion of carbon with maximum heat emission into the oxidizing zone of the dual-zone furnace into the slag melt. The mixture is then melted to form liquid slag entering the reduction zone, into which carbon-containing material, oxygen-containing blast and additional fluxes are supplied in the amounts necessary to reduce the oxides of the extracted metals into the metal phase and compensate for heat costs. At the same time, the ratio of the consumption of carbon-containing material per ton of extracted metal in the oxidation and reduction zones is maintained in the range of 0.3–2.5, and the specific oxygen consumption in these zones is in the range of 0.7–3.0. Periodically, before the release of the metal component of the smelting products, the melt in the slag siphon is heated by an electric arc at the boundary of the slag and metal phases to a temperature of 1350 to 1500 ° C, and before the release of the metal component, the melt in the siphon is left to stand for 10 to 15 minutes with the electrodes off. The disadvantages of this method include the low productivity of the process, high specific consumption of oxygen and fuel.

In the well-known analogue and the next closest analogue (prototype), it would be more correct to call the oxidative zone the melting one, because the processes occurring in this zone cannot, strictly speaking, be classified as oxidative from the point of view of the terminology generally accepted in metallurgy, since the ratio of oxygen and fuel corresponds to complete combustion the latter with maximum heat. Nevertheless, we retain the terminology, since we use the method below as a prototype.

Closest to the proposed invention in technical and technological essence is a method (RF Patent No. 2194781, С22В 23/02, С22В 19/00) for producing liquid metal in the processing of oxidized metal-containing natural raw materials and industrial materials (zinc-containing, copper-containing, nickel-containing, iron-containing and etc.). The method includes feeding a dual-zone furnace into the oxidizing (smelting) zone into a slag melt of a charge consisting of feedstock, fluxes, liquid or solid processed slag, carbon-containing material and oxygen-containing blast, melting the charge with the formation of slag entering the reduction zone into which the carbon-containing material, oxygen-containing blast and additional fluxes, the release of smelting products, and when processing oxidized raw materials, a carbon-containing material is fed into the oxidation zone of the furnace ial and oxygen in the quantities necessary for complete carbon combustion with maximum heat generation and the formation of liquid slag, and carbon-containing material and oxygen are supplied to the reduction zone in quantities necessary for the reduction of the oxides of the extracted metals and compensation of heat costs, while the ratio of the specific consumption of carbon-containing material per ton of recoverable metal in the oxidation and reduction zones is maintained within the range of 0.3-2.5, and the ratio of specific oxygen consumption in these zones is maintained in Gödel 0,7-3,0. In addition, the ratio of the amounts of oxygen supplied to the melt and to the gas phase above the melt in the reduction zone is maintained within the range of 0.1-0.5. The disadvantages of this method include the low productivity of the process, high specific consumption of oxygen and fuel. In particular, according to the method (RF Patent No. 2194781), industrial tests of processing technologies for dried oxidized nickel ore and sinter in a dual-zone Vanyukov furnace of OJSC Yuzhuralnickel Combine were conducted. The results of the tests performed are presented in the works: A.N. Fedorov, A.A. 2007. No. 12. S.33-37; V.I. Kostin. The experience of the Vanyukov furnace at OJSC Combine Yuzhuralnickel // Non-ferrous metals. 2008. No. 11. S.45-48. The main technical and technological characteristics of the process are presented in table 1.

As can be seen from the data presented, smelting ore is more preferable. There is a significant increase in productivity. A general decrease in energy costs is also observed (oxygen and coal consumption are reduced against a background of a slight increase in the consumption of natural gas).

The objective of the invention is to develop a method for the continuous processing of oxidized nickel ore to produce a metal (sulfide) melt, for example, ferronickel or nickel matte.

The technical result is an increase in the productivity of the smelting process and a decrease in the consumption of oxygen and carbon-containing fuel throughout the entire process chain from wet metal-containing raw materials to a marketable metal-containing product.

The claimed technical result is achieved in that in a method for processing oxidized nickel ore containing non-ferrous metals and iron, comprising supplying a dual-zone furnace to the oxidizing (melting) zone into a slag melt of a charge consisting of a mixture of feedstock and fluxes, liquid or solid processed slag, carbon-containing material and oxygen-containing blast supplied in quantities necessary for the complete combustion of carbon and hydrogen with maximum heat; melting the charge with the formation of slag melt entering the reduction zone of the furnace, into which oxygen-containing blast and carbon-containing material are supplied in the quantities necessary to restore the recoverable metals into the metal phase and compensate for heat costs by burning the gases of the reduction zone above the melt; production of smelting products; according to the invention, before feeding the mixture of feedstock and fluxes into the oxidizing (melting) zone of the furnace, they are fired and served with a temperature of 500-1300 ° C.

An additional supply of a carbon-containing reducing agent with a flow rate of 2 to 10% by weight of the higher non-ferrous metal and iron oxides contained in the initial mixture is possible at the firing stage.

It is possible to supply sulfur-containing materials with a flow rate of 100-530 kg of sulfur / t of metals recovered from the initial mixture into the reduction zone of the dual-zone furnace together with oxygen-containing blast and carbon-containing material.

In the proposed method, the feedstock (oxidized nickel ore) is first dried, reducing its moisture content to 10-15%. Then the mixture of feedstock and fluxes (if necessary, use them) is calcined in order to almost completely remove physical and crystallization (chemical) moisture, decomposition of carbonates, sulfates and other similar compounds. The result is a cinder, which, without cooling, is fed into a Vanyukov dual-zone furnace (see Fig. 1).

Cinder is served with a temperature of from 500 to 1300 ° C. Melting cinder with a temperature below 500 ° C leads to increased fuel and oxygen consumption in the oxidation (melting) zone of the Vanyukov furnace, since at these temperatures chemical moisture is practically not removed, carbonates, sulfates and other compounds do not decompose. When trying to obtain a cinder with a temperature above 1300 ° C, the material is melted and sintered, which disrupts the normal operation of kilns and prevents the crystallization (chemical) moisture from being removed and the decomposition of carbonates, sulfates and other compounds.

Firing can also be carried out with small additives of a carbon-containing reducing agent in order to restore higher oxides of non-ferrous metals and iron to lower ones. It is only necessary to add a reducing agent in small quantities, since the aim is to create poorly reducing conditions under which only partial reduction of higher non-ferrous metal and iron oxides to lower ones, in particular Fe ³⁺ to Fe ²⁺ , occurs, but they do not recover to the metallic state. The lower limit of the consumption of the carbon-containing reducing agent is limited to 2% of the mass of the starting raw materials and fluxes of the higher non-ferrous metal and iron oxides, since a consumption of less than 2% will not allow any appreciable amounts of higher oxides to be restored, and the upper limit is limited to 10%, as a higher consumption of carbon-containing reducing agent can lead to the production of a metal alloy. The inappropriateness of obtaining a metal alloy before melting in a Vanyukov furnace will be shown below.

Melting and hot cinder recovery are carried out in two stages, each of which is carried out in a separate zone of the furnace. At the first stage, the process of melting a hot cinder with obtaining a homogeneous slag melt is carried out, at the second stage, its reduction (reduction-sulfidation) depletion is performed. The process is carried out continuously, melting products: slag and metal (sulfide melt) are produced continuously.

A hot cinder, which is a calcined mixture of feedstock and fluxes, hard coal, oxygen-containing blast (a mixture of process oxygen and air) and carbon-containing fuel, is fed into the oxidizing (melting) zone. At the same time, the ratio of oxygen, hard coal and carbon-containing fuel is supplied in quantities necessary for the complete combustion of carbon and hydrogen with maximum heat. As a result of burning coal and fuel, the cinder melts to form slag melt.

At the recovery stage, the process of recovering slag melt, coming from the oxidizing (melting) zone, by a gas mixture consisting of oxygen-containing blast and carbon-containing fuel, with additional loading of hard coal, is implemented. In this case, the ratio of oxygen, carbon-containing fuel and coal is selected in such a way as to ensure the required extraction of non-ferrous metals and iron into the final product. The exhaust gases of the furnace recovery zone, containing CO and H ₂ in their composition, are burned over the melt with an oxygen-air mixture, which creates conditions for partial heat return to the melt and ensures the heat balance of the furnace recovery zone.

If it is necessary to obtain a sulfide melt (matte) as a final product, not only a metal, but a sulfide melt (matte), sulfur-containing materials are fed into the reduction zone together with oxygen-containing blast and carbon-containing material with a flow rate of 100-530 kg of sulfur / t of metals extracted from the feedstock and fluxes. As sulfur-containing materials can be used: elemental sulfur, pyrites, pyrite, gypsum, calcium sulfide, low-grade matte and other sulfidizers. The lower limit of the consumption of sulfur-containing material is limited by the need to obtain a sulfide intermediate, which is easy to grind, which corresponds to a sulfur concentration in it of ~ 7%. Subsequent processing of matte or the matte obtained from it when converting matte is carried out, as a rule, by hydrometallurgical methods or by oxidative firing in fluidized bed furnaces. In any case, the resulting Feinstein must be ground for further processing. The upper limit is limited due to the inadmissibility of producing matte with a sulfur concentration close to its stoichiometric content in lower sulfides (for example, FeS, Cu ₂ S, Ni ₃ S ₂ , CoS, etc.). An excessively high sulfur concentration in matte leads to a sharp decrease in the degree of sulfur assimilation by the melt and, consequently, to an increased conversion of sulfur to poor hardly utilizable exhaust gases.

The proof of the advisability of melting in a Vanyukov furnace precisely a calcined hot mixture of feedstock and fluxes will be considered using a specific example.

Example 1

The effectiveness of the proposed method will be shown by comparing the basic expenditure indicators of the technology for processing oxidized nickel ore to produce ferronickel with various options for preparing the feedstock for smelting in the Vanyukov dual-zone furnace.

Oxidized nickel ore of the Kimpersaysky deposit is considered as a raw material. The composition of the ore,% mass .: Ni - 0.90; Co - 0.076; Fe - 15.0; SiO ₂ 53.2; MgO - 6.5; Al ₂ O ₃ - 1.8; CaO - 0.9; Cr ₂ O ₃ - 1.2. Loss of ore mass during calcination (chemical moisture) - 11.1%. The content of H ₂ About (physical moisture) - 25%. Limestone is used as a flux, wt%: CaCO ₃ - 95.5; MgO - 3.2; SiO ₂ 0.2; Fe - 0.8%. The fuel is natural gas containing 94.2% CH ₄ . As a reducing agent, coal is used, containing,% wt .: C - 69.7; H - 3.0; S is 0.3; ash (SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , CaO, MgO) - 27%.

The necessary initial data for performing a comparative analysis of the main expenditure indicators were obtained as a result of pilot tests on the Vanyukov Institute Gipronickel Institute LLC with a bottom area of 0.4 m ² using oxidized nickel ore from the Kimpersai deposit as a feedstock. Tests have shown the possibility of obtaining high-quality rough ferronickel with a high level of nickel recovery. Received ferronickel containing,%: Ni - 20.1; C - 0.065; Si - 0.5; Cr 0.06; S is 0.6; P is 0.16. The content in the slag,%: Ni - 0.1. The extraction of Ni in ferronickel is 90.3%. The test results were the basis for calculating the material and thermal balances of the process of producing ferronickel in a two-zone Vanyukov furnace for the case of implementation on an industrial scale.

Regardless of the chosen option for preparing oxidized nickel ore and flux for smelting, the first stage requires an ore drying operation, as a result of which the ore moisture should be reduced from 25 to 15%. Obtaining ore with a moisture content of less than 15% is impractical due to an increase in dust removal during its further processing. The drying process is carried out, as a rule, in rotary drying drums. Natural gas, fuel oil, pulverized coal or other types of fuel can be used as fuel. Since all of the data presented below will relate to the processing of ores from the Kimpersaysky deposit, we choose natural gas available for this region as a fuel. Calculations of the heat balance of the ore drying operation showed that the consumption of natural gas is 10.3 nm ³ / t of processed ore with an initial content of H ₂ O (physical moisture) of 25%.

Ore processing with a moisture content of 15% can be carried out in various ways.

1. Smelting ore with a moisture content of 15% and limestone with a moisture content of 5% in a dual-zone Vanyukov furnace to produce ferronickel.

2. Calcination of ore and limestone in tubular rotary kilns with complete dissociation of CaCO ₃ and removal of all types of H ₂ O (physical and chemical). The resulting cinder is cooled (adopted temperature 25 ° C) and processed in a dual-zone Vanyukov furnace to obtain ferronickel.

3. Calcination of ore and limestone in tubular rotary kilns with complete dissociation of CaCO ₃ and removal of all types of H ₂ O (physical and chemical). The resulting cinder in hot form (temperature - 900 ° C) is processed in a dual-zone Vanyukov furnace to obtain ferronickel.

4. Reductive roasting of ore and limestone in tubular rotary kilns with complete dissociation of CaCO ₃ , removal of all types of H ₂ O (physical and chemical) and partial reduction of the oxide-silicate forms of iron and nickel to a metallic state. Partially reduced cinder (reduction rate of Fe → Fe _met - 0.5%; Ni → Ni _met - 79%; ratio Fe ³⁺ / Fe ²⁺ - 90/10) is processed in a single-zone Vanyukov furnace to produce ferronickel.

5. Reductive roasting of ore and limestone in tubular rotary kilns with complete dissociation of CaCO ₃ , removal of all types of H ₂ O (physical and chemical) and the necessary degree of reduction of the oxide-silicate forms of iron to nickel to a metallic state to obtain a 20% ferronickel. The recovered cinder (reduction rate Fe → Fe _met - 21%; Ni → Ni _met - 99%; ratio Fe ³⁺ / Fe ²⁺ - 93/7) is processed in a single-zone Vanyukov furnace to produce ferronickel.

We perform the calculations of the main indicators for the five above options. The initial conditions for the calculation were as follows:

- the amount of ore processed with a H ₂ O content of 25% is 1,467,000 t / year;

- the amount of nickel in a 20% ferronickel is 11480 t / year;

- Nickel recovery in ferronickel - 90.3%;

- limestone consumption (dry weight) - 20% by weight of dry ore. The composition of limestone is presented above, the content of H ₂ O - 5%;

- natural gas is used as fuel for heating drying ovens (options 1-5), kilns (options - 2-5), Vanyukov ovens (options 1-5). The calorific value of natural gas is 34543 kJ / nm ³ ;

- coal is used as a reducing agent for roasting a mixture of ore and limestone (options 4, 5), as a partial replacement of natural gas in the oxidizing (melting) zone of the Vanyukov furnace (options 1-3), as a reducing agent in the second zone of the Vanyukov furnace (options 1-3) or a single-zone furnace (options 4, 5). The composition of coal is presented above, the content of H ₂ O - 5%, calorific value of coal - 23419 kJ / kg;

- slag temperature - 1600 ° C;

- the temperature of ferronickel - 1530 ° C;

- enrichment of blast with oxygen in the Vanyukov furnace - 90%;

- the average heat flow to the caissons of the melting zone is 410 MJ / m ² · hour;

- the average heat flow to the caissons of the recovery zone is 376 MJ / m ² · hour.

The calculation results of the main indicators of the process of smelting the feedstock and flux of varying degrees of preparedness in the oxidizing (melting) zone of the Vanyukov furnace are presented in table 2 and figure 2, 3. As can be seen from the data presented, the sharpest decrease in the main energy parameters and the sharpest increase in productivity the melting zone is observed during the transition from smelting raw ore to smelting a calcined mixture of feedstock and flux, not subjected to preliminary reduction. If the mixture of feedstock and flux is additionally subjected to preliminary reduction (options 4 and 5), then the energy costs continue to decrease, but this is already happening to a much lesser extent.

However, it should be remembered that the implementation of the firing process and, especially, the implementation of regenerative firing require fuel costs (not only the use of process oxygen). Therefore, of greater interest is the comparison of the total energy costs for the implementation of a particular version of the technological scheme. The results of this comparison are presented below (see table 3 and figure 4).

As can be seen from the presented data, option 3 is characterized by the lowest energy costs, in which it is supposed to carry out preliminary non-reduction firing of the mixture of the feedstock and flux with subsequent melting of the hot cinder in the Vanyukov dual-zone furnace. For almost all energy costs, this option is most preferable. Only the consumption of natural gas is not minimal in this embodiment, but, as can be seen from FIG. 4, its consumption is only 13% higher than in option 1, where the consumption of natural gas is the smallest. Comparison of the total costs of coal and natural gas, converted into units of equivalent fuel, makes the advantages of option 3 as the option with the lowest energy costs (see figure 5) finally clear.

Consider the reasons for the greater efficiency of the invention (option 3) compared with options 1 and 2.

In option 1, in comparison with option 3, a mixture of feedstock and flux with a high content of physical, chemical moisture and calcium carbonate enters the smelting process. Combining the processes of moisture removal, dissociation of carbonates, heating, melting and bringing the temperature of the melt to 1600 ° C in the melting zone of the furnace with intensive cessated cooling leads to its low productivity. Therefore, due to the limited amount of blast that can be supplied through each lance of the furnace, and the natural restrictions on the intensity of the blast, it is necessary to process a significant amount of raw material to have a significant area of the melting zone and, therefore, a significant consumption of oxygen, and hence fuel (ratio between fuel and oxygen remains strictly fixed). Moreover, even for a relatively small volume of produced ferronickel (see above), the area of the melting zone is excessive (54.7 m ² ), which necessitates the construction of not just one, but two dual-zone furnaces. Since the processes of removing physical and chemical moisture and the decomposition of carbonates occur at significantly lower temperatures than the melting temperature, and the hardware design of the firing process does not require coffered elements in the furnace structures, it is advisable to separate the calcination and dissociation processes from the melting process. The appropriateness of the separation of processes logically follows from the maximum efficiency of using each of the metallurgical units: the calcination and dissociation processes occur in a kiln, which is characterized by low heat losses, and the melting and reduction processes are carried out in a bubbler type furnace, which is characterized by high rates of melting, melt homogenization , reduction of metal oxides and separation of smelting products.

As can be seen from the results of the above calculations (see Figs. 4 and 5), the separation of calcination and dissociation from the melting process is energetically more profitable: oxygen and fuel consumption are reduced.

Despite the fact that we use natural gas in the firing process, in general, its consumption over the entire process chain increases less significantly than the consumption of oxygen and coal. If natural gas and coal are converted to equivalent fuel, then the advantages of option 3 become completely obvious (see figure 5).

A similar pattern is confirmed by a comparison of the indicators achieved at the Vanyukov industrial dual-zone furnace of OJSC Yuzhuralnickel Combine. However, the decrease in oxygen and coal consumption during sintering ore smelting is less significant compared to the smelting of dried ore (see Table 1) than in the options we considered for the following reasons:

1. With a decrease in the area of the hearth of the Vanyukov furnace melting zone below 10 m ² , heat losses increase disproportionately.

2. Limestone was not subjected to preliminary firing.

In the example we are considering, in option 2, compared with the proposed invention (option 3), all the main process indicators are worse, which is quite obvious, since it is more advisable not to cool the hot cinder, but to immediately put it on the heat.

As a further improvement in the performance of the present invention, there is a method comprising the step of pre-firing a mixture of feedstock and flux to restore higher non-ferrous metal oxides to lower ones. It is, first of all, about the reduction of Fe ³⁺ to Fe ²⁺ . This, firstly, reduces the content of Fe ³⁺ in the slag melt of the melting zone, and, therefore, reduces the likelihood of heterogenization of the slag due to the formation of magnetite. Secondly, the costs of oxygen, fuel and reducing agent in the reduction zone of the furnace, which has a tense thermal balance, are reduced.

It should be emphasized once again that the improvement of the present invention can only go along the path of creating weakly reducing conditions under which only partial reduction of Fe ³⁺ to Fe ²⁺ occurs, but practically no reduction of non-ferrous metal and iron oxides to a metallic state occurs. Otherwise, energy costs begin to increase again.

As can be seen from table 3 and figure 4, 5, options 4 and 5, in which the oxides are reduced to a metallic state, turned out to be less energetically favorable than option 3. Here two main reasons can be mentioned. Firstly, as calculations of the heat balance have shown, the combination of melting and reduction operations in the Vanyukov furnace is not energetically justified. As can be seen from table 3, the total consumption for both zones of the Vanyukov furnace in option 3 of coal (11200 kg / t Ni), natural gas (3224 nm ³ / t Ni) and oxygen (14728 nm ³ / t Ni) is even lower than single-zone furnaces in options 4 and 5. Secondly, in options 4 and 5, compared with option 3, the costs of coal and natural gas are added, which are necessary for preliminary reduction of the mixture of feedstock and flux at the firing stage. Particularly significant coal costs are needed in option 5, in which the task was to produce a cinder with the degree of iron reduction required to obtain a 20% ferronickel (~ 21%). Such a deep recovery of the feedstock requires significant energy costs at the firing stage, which can be justified in the case of subsequent melting of the cinder in electric furnaces, but not justified in the case of subsequent melting of the cinder in oxygen-blown furnaces, where it is necessary to conduct iron and nickel reverse oxidation processes melting in highly reducing conditions. Therefore, in spite of the great simplicity of the design of the Vanyukov single-zone furnace compared to the dual-zone furnace, the use of a single-zone furnace to obtain ferronickel can hardly be considered expedient, and therefore, the method according to the invention is more preferable in comparison with options involving the restoration of metal oxides to a metallic state before melting in Vanyukov’s furnace.

Example 2

In this example, a method for producing matte in the processing of oxidized nickel ore with various sulfidization consumption is considered. The starting material was a mixture of oxidized nickel ores of the Cheremshansky, Serovsky and Kimpersaysky deposits of the following composition: Ni - 0.91; Co - 0.073; Fe - 18.6; SiO ₂ 48.4; MgO - 13.5; Al ₂ O ₃ - 3.9; CaO - 2.7; Cr ₂ O ₃ - 0.5. Loss of ore mass during calcination (chemical moisture) - 9.0. The content of H ₂ About (physical moisture) - 10%. As the flux used limestone,% mass .: CaCO ₃ - 95.5; MgO - 3.2; SiO ₂ 0.2; Fe - 0.8%. The fuel is natural gas containing 94.2% CH ₄ . As a reducing agent used coal containing,% mass .: C - 69.7; H - 3.0; S is 0.3; ash (SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , CaO, MgO) - 27%. Pyrite with a content of: Fe — 39.7; S - 41.8.

The tests were carried out on experimental installations of Gipronickel Institute LLC. The firing of the mixture of feedstock and flux was carried out on a tubular rotary kiln with overall dimensions of 5.0 × 0.5 m with a capacity of up to 200 kg / h on a processed charge. The resulting cinder with a temperature of 600-700 ° C was melted in a Vanyukov furnace with a hearth area of 0.4 m ² .

The source data, main indicators and compositions of the obtained melting products are presented in tables 4 and 5.

Here are examples of calculating the consumption of sulfur per 1 ton of recoverable metals for the performed experimental studies. Pyrite with an S content of 41.8% by weight was used as a sulfidizing agent.

Example 2.1 (heat No. 1 in tables 4 and 5)

The amount of loaded pyrite was 40 kg

Consequently, the sulfur consumption was 40 · 0.418 = 16.72 kg

The amount of matte received - 47.0 kg

The number of metals in matte: 47.0 · (0.19 + 0.527 + 0.0121) = 34.27 kg. In this calculation, not only metals recovered from the slag melt, but also metals converted to matte together with a sulfidizer are considered to be extracted.

Then the sulfur consumption per unit mass of recoverable metals will be: 16.72 / 34.27 = 488 kg / t of metals.

Example 2.2 (heat No. 2 in tables 4 and 5)

The amount of loaded pyrite was 5 kg

Therefore, the sulfur consumption was 5 · 0.418 = 2.09 kg

The amount of matte obtained is 35.8 kg

The number of metals in matte is 35.8 · (0.636 + 0.284 + 0.018) = 33.6 kg

Then the sulfur consumption per unit mass of recoverable metals will be: 2.09 / 33.6 = 62 kg / t of metals.

The resulting matte is highly metallized, contains 4.9% and is not suitable for producing high-quality Feinstein or for processing by hydrometallurgical methods due to the impossibility of its high-quality grinding.

Example 2.3 (heat No. 3 in tables 4 and 5)

The amount of loaded pyrite was 65 kg

Consequently, the sulfur consumption was 65 · 0.418 = 27.2 kg

The amount of matte obtained - 56.6 kg

The number of metals in matte 56.6 · (0.514 + 0.169 + 0.0101) = 39.2 kg

Then the sulfur consumption per unit mass of recoverable metals will be: 27.2 / 39.2 = 694 kg / t of metals.

The resulting matte contains an excess of sulfur. The degree of sulfur absorption decreased to 59.4%, which creates difficulties with the utilization of sulfur dioxide.

Claims (3)

1. A method of processing oxidized nickel ore containing non-ferrous metals and iron, comprising feeding a dual-zone furnace into a slag melt of a charge consisting of feedstock and fluxes, liquid or solid processed slag, carbon-containing material and oxygen-containing blast, supplied in quantities necessary for the complete combustion of carbon and hydrogen with maximum heat, melting the mixture with the formation of slag melt entering the reduction zone of the furnace, in which they supply oxygen-containing blast and carbon-containing material in the quantities necessary to restore the recoverable metals to the metal phase and compensate for heat costs by burning the gases of the reduction zone above the melt, the release of smelting products, characterized in that before supplying the feedstock and fluxes to the oxidizing - smelting zone their mixture is preliminarily fired and fed at a temperature of 500-1300 ° C. 2. The method according to claim 1, characterized in that at the stage of preliminary calcination of the mixture of feedstock and fluxes, carbon-containing material is fed in an amount of 2-10% by weight of the higher non-ferrous metal and iron oxides contained in the calcined charge. 3. The method according to claim 1, characterized in that in the recovery zone of the dual-zone furnace together with an oxygen-containing blast and carbon-containing material serves sulfur-containing material with a flow rate of 100-530 kg of sulfur / t of metals recovered from the feedstock.

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