WO2012125011A1 - Method for processing raw material comprising non-ferrous metals and iron - Google Patents

Abstract

The invention relates to the metallurgical industry, primarily to nickel and cobalt metallurgy, and concerns the processing of oxidized metal-containing natural raw material and technogenic materials. The method comprises feeding a charge consisting of the initial ore, fluxes, liquid or solid workable slag, carbon-containing material and oxygen in an oxygen-containing blast into the oxidative zone of a furnace in the quantities necessary for the complete combustion of the carbon. The moist ore is dried and hardened by exhaust gases from the furnace before being fed into the furnace. The charge is melted in the oxidative smelting zone of a single zone furnace to form a liquid slag. The liquid slag is discharged into an electric furnace, in which the oxides are reduced to a metallic phase as carbon-containing material is fed in. The invention is directed towards increasing the extraction of metals to produce a matte or ferroalloy by means of additional reduction, with a lower consumption of heat.

Description

 METHOD FOR PROCESSING NON-COLORED RAW MATERIALS

 METALS AND IRON

 (Main text)

 The invention relates to the field of metallurgy and relates to methods for producing liquid metal in the processing of oxidized metal-containing natural raw materials and industrial materials. The invention can be used for the production of nickel, copper and iron, etc.

 A known method of continuous processing of raw materials containing non-ferrous metals and iron, in particular the production of ferronickel or nickel matte from oxidized nickel ores (RF patent for the invention Ns 2194781, publ. 20.12.2002, bull.> 35).

The method includes feeding into the oxidized zone of a dual-zone furnace in a slag melt of the charge, carbon-containing material and oxygen in an oxygen-containing blast in quantities necessary for complete combustion of carbon with maximum heat generation, melt of the charge by the formation of liquid slag entering the reduction zone, into which carbon-containing material, oxygen-containing blast and additional fluxes are supplied in quantities necessary for reduction of oxides of recoverable metals in the metal phase and compensation of heat costs, maintaining the ratio of the consumption of carbon-containing material per ton of recoverable metal in the oxidation and reduction zones 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, the release of smelting products from the reduction zone of the furnace.

 The disadvantage of this known method is:

 - the formation of a heterogeneous intermediate layer at the boundary of the slag and metal baths with a decrease in temperature in the tuyere zone, which complicates the separation of slag and metals;

 - when the fuel supply is stopped, the blast quickly cools the melt, it may froth first and then freeze.

 The technical result of the proposed method is to increase the extraction of metals in matte (ferroalloy) due to their additional recovery and improved separation of slag and metal phases.

Also known is a method (RF patent for the invention N ° 2324751, publ. 20.1 1.2007, bull. 4 from 05.20.2008 and RK patent for the invention jVs 21937, publ. 15.12.2009, bull.] H ° 12), in which before release of the metallic phase of the smelting products, the melt in the slag siphon is periodically heated by an electric arc. An arc is formed at the slag - metal phase boundary, with additional reduction of metals in the metal phase due to the consumption of graphite electrodes. There is also a depletion of slag due to mixing of the melt with an arc and an increase in temperature, followed by settling of the melt before the discharge of the metal phase.

Example: Oxidized nickel ore containing 1.07% Ni is processed; 24% Fe; 48% Si0 ₂ . In the oxidized zone load 41, 7 t / h of ore with a moisture content of 10%; 12.8 t / h of limestone; 7.4 t / h of coal; 9740 nm / hour technical oxygen; 2300 nm / hour of air.

 In the recovery zone load 2t / hour of coal; 1.3 t / h of sulfuric

3 3 3 pyrites; 1500 nm / h of oxygen and 800 nm / h of air into the melt and 760 nm / h of oxygen and 300 nm ³ / h of air for afterburning.

 Before the discharge of the metal phase, a direct current is supplied to the slag siphon through graphite electrodes. The melt in a siphon is heated to a temperature

1350-1500 ° C, after which the voltage at the electrodes is turned off. The metal phase is left to stand for 10-15 minutes before draining.

 The output of the metal phase is 2 t / h, which is 0.2 t / h higher than in the known method.

 Both methods require separate fuel consumption and other expenses for ore preparation (drying and calcining of often wet feedstock). In addition, a dual-zone furnace, due to temperature differences in different zones, requires a higher heat consumption compared to the proposed method. This makes these two methods - analogues less effective and significantly more expensive than the proposed method Sadmelt.

The proposed Sadmelt method from the two analogues listed above, as well as from the RK patent for the invention N ° 24888, publ. 15.1 1.201 1, 6ΚΧΙΊ.Ν_> 1 1 differs in that it consists of a combination of several processes (see. Fig.): Drying and calcining up to 800-1000 ° С of wet ore by the furnace exhaust gases; then, feeding into the slag melt of the oxidation-melting zone of the single-zone furnace charge, consisting of calcined ore, 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; Further, the charge is melted in the oxidation-melting zone with the formation of liquid slag entering a separate unit - a direct current electric furnace. Carbon-containing material, additional fluxes in quantities necessary for the reduction of the oxides of the extracted metals in the metal phase and compensation of heat costs are supplied to this unit, which is powered by direct current energy. At the same time, the ratio of the specific energy consumption per ton of recoverable metal is maintained in the range of 0.17-0.20, and the specific oxygen consumption is in the range of 0.07-0.08, the coal consumption is 0.08-0.09. The method allows to reduce moisture (both physical and crystalline), due to this, increase the content of valuable components (base metals) by 0.2% or more, reduce the cost of 1 ton of nickel in finished products by 50% or more compared to the indicated options - analogues.

 The proposed method is planned in the design and construction of non-ferrous metal and iron factories both for the stages of modernization of production in order to increase the content of basic metals in commercial products, and for new construction of factories with initially the best parameters.

An example of the parameters of the proposed method Sadmelt:

 For oxidized ore containing 0.5-0.7% nickel, not less than 0.05% cobalt and higher than 20% iron, when used in a single-zone furnace with an oxidation zone of 7.2 m, without using natural gas, hourly indicators of smelting in single-zone furnaces are as follows:

 wet ore 44.2 t, calcined ore 28.9 t, hot limestone 9.2 t (ore and limestone are supplied from the calcination system), coal 1 1, 5 t (blown into the melt), process oxygen 6.2 thousand m3 , air in the oxygen-air mixture of 1.4 thousand m3, air for afterburning in the exhaust gases 11.9 thousand m3, matte 1.5 tons, waste slag 33.9 tons, exhaust gases 36.8 thousand m3; sulfur in a direct current furnace 0.7t.

(56) List of documents used in the search: SU 252616, 03/17/1970; SU 377368, 06/21/1973; US 4,139,371 A, 02/13/1979; US 4,252,560 A, 02.24.1981; GB 2161835 A, 1/22/1986; Vanyukov A.V. and others. Melting in a liquid bath. M .: Metallurgy, 1988, p.166-173; EP 0276032 A1, 07/27/1988; RU 2130975 C1, 05.27.1999; SU 1292343 A1, 06/10/1999; WO 01/68927 A1, 09/20/2001; RU 2194781 C2, 12.20.2002; RU 2324751 C2, 11.20.2007; KZ 21937 A4, 12/15/2009, Z 24888 A4, 11/15/2011.

Claims

 Claim A method for the processing of raw materials containing non-ferrous metals and iron, including feeding to the oxidized zone a charge consisting of feedstock, fluxes, liquid or solid processed slag, carbon-containing material and oxygen in oxygen-containing blast in quantities necessary for the complete combustion of carbon, the melting of the mixture with the formation of liquid slag, which can be combined with several processes: drying and calcining of moist ore up to 800-1000 ° С of flue gases from the furnace; then supplying to the slag melt of the oxidation-melting zone of a single-zone furnace charge consisting of calcined ore, fluxes, liquid or solid processed slag, carbon-containing material and oxygen in an oxygen-containing blast in the quantities necessary for complete combustion of carbon with maximum heat; then the charge is melted in the oxidation-melting zone with the formation of liquid slag entering a separate unit - a direct current electric furnace; carbon-containing material, additional fluxes in quantities necessary for the reduction of the oxides of the extracted metals in the metal phase and compensation of heat costs are supplied to this unit, which operates at the expense of direct current energy; while maintaining the ratio of the specific energy consumption per ton of recoverable metal in the range of 0.17-0.20, and the specific oxygen consumption in the range of 0.07-0.08, coal consumption - 0.08-0.09.