METHODE DE PRODUCTION DE METAL EN FUSION FAIT ESSENTIELLEMENT DE MANGANESE ET DE FER

METHOD OF PRODUCING MOLTEN METAL CONSISTING MAINLY OF MANGANESE AND IRON

Abrégé anglais

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 in a shaft filled with solid reducing agent.

Revendications

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The embodiments of the invention, in which
an exclusive privilege or property is claimed, are defined
as follows:
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.

Description

3 17485S
-- 1 --
"ME~HOD OF PRODUCING MOLTEN METAL CONSISTING MAINL~ OF
MANGANESE AND IRO~"
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 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
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~174855
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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 manganese-containing metals
with silicon contents above 5%, a pulverulent material
rich in silicon dioxide is added to a pulverulent
material containing manganese oxides.

~ 174855
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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 Ferromanqanese
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 12 - 14% Mn. The quantity of slag
was just 500 kg per ton of metal.

1 1~4855
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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 1200C and the
tapped -off metal and slag had a temperature of about
1430C.
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 Man~anese
Pulverulent raw material consisting of a
mixture of manganese ore, quartz and lime, and containing
about 35% Mn and 38`~ SiO2, 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, 18/o Si and 1.5% C. The manganese yield was therefore
about 85%.
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~174855
The quantity of slag was 560 kg/ton of metal
and contained about 18% MnO.
At the same time, a quantity of 1300 M gas
was also obtained per ton of metal (at S.T.P.), with a
composition of about 30`~/O H2 and 70% CO.
The energy consumption was 4500 kWh. The
temperature of the gas produced was about 1300C. The
metal and slag tapped off had a temperature of about
1550C.
.
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