GB2094354A

GB2094354A - Producing Mn-Fe alloy by carbothermic reduction

Info

Publication number: GB2094354A
Application number: GB8131411A
Authority: GB
Original assignee: SKF Steel Engineering AB
Current assignee: SKF Steel Engineering AB
Priority date: 1981-03-09
Filing date: 1981-10-19
Publication date: 1982-09-15
Also published as: ZA811540B; FI71351C; PL234266A1; DD202185A5; BR8200425A; MX157301A; CS226043B2; AU7756381A; FR2501238B1; IT8125206A0; KR830007865A; DE3141926C2; GB2094354B; CA1174855A; SE8105120L; ES506883A0; SU1069632A3; ZW27981A1; IN155076B; AT385518B

Abstract

A method is provided for producing molten metal consisting mainly of manganese and iron. The method comprises the steps of injecting a pulverulent material, containing manganese oxide, directly into a smelting reduction zone, together with coal and/or hydrocarbons, in powder form. The smelting reduction zone is continuously produced by the supply of heat energy e.g. from a plasma generator in a shaft filled with solid reducing agent. Examples include the production of ferromanganese and ferrosilicon manganese.

Description

SPECIFICATION Method of producing molten metal consisting mainly of manganese and iron This invention relates to a method of producing molten metal consisting mainly of manganese and iron. The molten metal may also contain silicon in a particular embodiment.

In certain known methods for the production, for example, of ferro-manganese in the Thysland Mohle furnaces, the supply of raw material is rendered difficult because both the manganese carrier and the reducing agent must be in pieces.

The furnace constructions used in these known methods are also difficult to make gas-tight, and this gives rise to appreciable problems in respect of rational utilisation of the energy content of the waste gas, and in addition the prior art processes are made difficult by the need to comply with existing environmental requirements.

In another known method, the PLASMASMELT method, which is used for the production of metals from oxidic material, the reduction is carried out in two stages, i.e. by a preliminary reduction in the solid phase and a final reduction in connection with the smelting.

It has, however, been found that this known method, when applied to material containing manganese oxide, provides no appreciable energy saving because of the preliminary reduction stage, while appreciable problems arise due to the tendency of manganese oxides to smear at the appropriate preliminary reduction temperatures.

Also many materials which contain manganese oxides have a particle size which is too small to enable processing of the materials in existing preliminary reduction stages.

It has now, surprisingly, been found that the above disadvantages and drawbacks can be solved by utilising a process according to the invention.

According to this invention there is provided a method of producing molten metal comprising mainly manganese and iron, which comprises injecting a pulverulent material containing manganese oxide directly into a smelting reduction zone, together with coal and/or hydrocarbons in powder form, said zone being continuously produced, with the supply of heat energy, in a shaft filled with solid reducing agent.

The metal produced may, if desired, contain silicon and will probably also contain incidental ingredients and impurities.

In one advantageous embodiment of the invention, in the production of molten manganesecontaining metals with silicon contents above 5%, a pulverulent material rich in silicon dioxide is added to a pulverulent material containing manganese oxides.

The continuous heat energy supply to the reducing zone may advantageously be produced by a plasma generator.

The invention will now be described in greater detail hereinafter with reference to the following examples.

EXAMPLE 1 Production of Ferromanganese A pulverulent mixture comprising manganese ore and slag-formers, (constituting a raw material containing about 48% manganese and 7% iron) was injected directly into a reaction zone formed in the bottom part of a coke-filled shaft situated in front of a plasma generator supplying this reaction zone with heat energy.

A reducing agent comprising approximately 400 kg of powdered coal per ton of FeMn, was injected together with the above raw material into the shaft, and this quantity of reducing agent corresponds to a good two-thirds of the total reducing agent requirement. The remainder of the reducing agent consisted of the column of coke in the shaft.

A metal was obtained from the shaft, the metal containing 79.1% Mn and 6.0% C, corresponding to a Mn yield of about 87%. The slag has a basicity of 1.3-1.6 and contained 1214% Mn. The quantity of slag was just 500 kg per ton of metal.

The process also yielded some 1000 M3 gas/ton metal (at S.T.P.) with a composition of about 25% H2 and 75% CO.

The energy consumption was 300 kWh/ton, the temperature of the outgoing gas was about 1 2000C and the tapped-off metal and slag had a temperature of about 14300 C.

It will be apparent from the above Example that ferromanganese can be produced without difficulty by a method according to the invention.

EXAMPLE 2 Production of Ferrosilicon Manganese Pulverulent raw material consisting of a mixture of manganese ore, quartz and lime, and containing about 35% Mn and 38% Six2, was injected, without preliminary reduction, directly into the reaction zone in the same way as in Example 1, together with powdered coal.

The powdered coal was the main reducing agent. A smaller partial reduction and carbonization of the metal was obtained by coke from the stack in the shaft. About 550 kg of coal/ton of metal was supplied during the process, and this was more than 80% of the total requirements.

The metal tapped from the shaft contained 65% Mn, 1 8% Si and 1.5% C. The manganese yield was therefore about 85%.

The quantity of slag was 560 kg/ton of metal and contained about 18% MnO.

At the same time, a quantity of 1300 M3 gas was also obtained per ton of metal (at S.T.P.), with a composition of about 30% H2 and 70% CO.

The energy consumption was 4500 kWh. The temperature of the gas produced was about 1 3000C. The metal and slag tapped off had a temperature of about 1 5500C.

1. A method of producing molten metal comprising mainly manganese and iron, which comprises injecting a pulverulent material

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Method of producing molten metal consisting mainly of manganese and iron This invention relates to a method of producing molten metal consisting mainly of manganese and iron. The molten metal may also contain silicon in a particular embodiment. In certain known methods for the production, for example, of ferro-manganese in the Thysland Mohle furnaces, the supply of raw material is rendered difficult because both the manganese carrier and the reducing agent must be in pieces. The furnace constructions used in these known methods are also difficult to make gas-tight, and this gives rise to appreciable problems in respect of rational utilisation of the energy content of the waste gas, and in addition the prior art processes are made difficult by the need to comply with existing environmental requirements. In another known method, the PLASMASMELT method, which is used for the production of metals from oxidic material, the reduction is carried out in two stages, i.e. by a preliminary reduction in the solid phase and a final reduction in connection with the smelting. It has, however, been found that this known method, when applied to material containing manganese oxide, provides no appreciable energy saving because of the preliminary reduction stage, while appreciable problems arise due to the tendency of manganese oxides to smear at the appropriate preliminary reduction temperatures. Also many materials which contain manganese oxides have a particle size which is too small to enable processing of the materials in existing preliminary reduction stages. It has now, surprisingly, been found that the above disadvantages and drawbacks can be solved by utilising a process according to the invention. According to this invention there is provided a method of producing molten metal comprising mainly manganese and iron, which comprises injecting a pulverulent material containing manganese oxide directly into a smelting reduction zone, together with coal and/or hydrocarbons in powder form, said zone being continuously produced, with the supply of heat energy, in a shaft filled with solid reducing agent. The metal produced may, if desired, contain silicon and will probably also contain incidental ingredients and impurities. In one advantageous embodiment of the invention, in the production of molten manganesecontaining metals with silicon contents above 5%, a pulverulent material rich in silicon dioxide is added to a pulverulent material containing manganese oxides. The continuous heat energy supply to the reducing zone may advantageously be produced by a plasma generator. The invention will now be described in greater detail hereinafter with reference to the following examples. EXAMPLE 1 Production of Ferromanganese A pulverulent mixture comprising manganese ore and slag-formers, (constituting a raw material containing about 48% manganese and 7% iron) was injected directly into a reaction zone formed in the bottom part of a coke-filled shaft situated in front of a plasma generator supplying this reaction zone with heat energy. A reducing agent comprising approximately 400 kg of powdered coal per ton of FeMn, was injected together with the above raw material into the shaft, and this quantity of reducing agent corresponds to a good two-thirds of the total reducing agent requirement. The remainder of the reducing agent consisted of the column of coke in the shaft. A metal was obtained from the shaft, the metal containing 79.1% Mn and 6.0% C, corresponding to a Mn yield of about 87%. The slag has a basicity of 1.3-1.6 and contained 1214% Mn. The quantity of slag was just 500 kg per ton of metal. The process also yielded some 1000 M3 gas/ton metal (at S.T.P.) with a composition of about 25% H2 and 75% CO. The energy consumption was 300 kWh/ton, the temperature of the outgoing gas was about 1 2000C and the tapped-off metal and slag had a temperature of about 14300 C. It will be apparent from the above Example that ferromanganese can be produced without difficulty by a method according to the invention. EXAMPLE 2 Production of Ferrosilicon Manganese Pulverulent raw material consisting of a mixture of manganese ore, quartz and lime, and containing about 35% Mn and 38% Six2, was injected, without preliminary reduction, directly into the reaction zone in the same way as in Example 1, together with powdered coal. The powdered coal was the main reducing agent. A smaller partial reduction and carbonization of the metal was obtained by coke from the stack in the shaft. About 550 kg of coal/ton of metal was supplied during the process, and this was more than 80% of the total requirements. The metal tapped from the shaft contained 65% Mn, 1 8% Si and 1.5% C. The manganese yield was therefore about 85%. The quantity of slag was 560 kg/ton of metal and contained about 18% MnO. At the same time, a quantity of 1300 M3 gas was also obtained per ton of metal (at S.T.P.), with a composition of about 30% H2 and 70% CO. The energy consumption was 4500 kWh. The temperature of the gas produced was about 1 3000C. The metal and slag tapped off had a temperature of about 1 5500C. CLAIMS

1. A method of producing molten metal comprising mainly manganese and iron, which comprises injecting a pulverulent material containing manganese oxide directly into a smelting reduction zone, together with coal and/or hydrocarbons in powder form, said zone being continuously produced, by supply of heat energy, in a shaft filled with solid reducing agent.

2. A method according to claim 1, wherein the metal contains at least 5% silicon, a pulverulent material rich in silicon dioxide being added to the pulverulent material containing manganese oxide.

3. A method according to claim 1 or 2, wherein the heat energy supplied to the reduction zone is produced by a plasma generator.

4. A method according to claim 1 substantially as described in Example 1 or 2.