JPS59159963A - Production of high chromium molten metal - Google Patents

Abstract

PURPOSE:To produce inexpensively a high chromium molten metal at a high yield of Cr by injecting powdery and granular chromium oxide together with oxidizing carrier gas into the molten iron in a refining vessel and supplying separately a carboneous material into the molten iron then refining the molten iron. CONSTITUTION:A molten iron 5 is charged into a body 1 of a converter, etc. Powdery and granular chromium oxide consisting of chromium ore or preliminarily reduced chromium ore is mixed with a flux such as CaO, etc. if necessary and such oxide is injected by oxidizing carrier gas consisting of oxygen or oxidizing gas contg. oxygen into said iron 5 through a top blowing lance 3 or bottom blowing tuyere 2; at the same time, a carboneous material such as coal, coke or the like is separately supplied into the iron 5. The oxidizing gas is supplied through said lance 3 or tuyere 2 and while the molten iron is stirred by introducing gaseous N2, gaseous Ar, etc. preferably through the tuyere 2, the molten iron is refined. The high chromium molten metal contg. <40% Cr is thus produced from the inexpensive raw materials with small energy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for melting high-chromium molten metal, and in particular to a method for melting high-chromium molten metal, in particular, by adding powdered or granular chromium oxide to the molten iron in a converter containing the molten iron or a refining vessel similar to Ir1M. A preferred method for producing high chromium steel with a 'p:', ar content of less than 40% by injection refining is described.

Conventionally, stainless steel melting process was carried out using an electric furnace.
A ferroalloy such as ear% FeNi, scrap, etc. is melted to produce a mother molten metal, and then various refining equipment, ie,
The majority of methods involved performing decarburization, refining and desulfurization using a converter, AOD, VOD, etc., and in some cases finishing refining using a secondary refining device, that is, an RH degassing device, followed by casting.

However, in these methods, a large amount of energy (electrical energy in the case of production using an electric furnace) is usually consumed in the production of ferroalloys such as Fear and FeNi, and the ferroalloys cooled to room temperature are Melting stainless steel in an electric furnace during melting increases energy costs, and improvements are needed from the perspective of energy conservation.

In line with the recent trend toward lowering the grade of ore and turning it into powdered iron, the general production of ferroalloys involves first pre-processing and agglomerating the powder and granular ore, and then using an electric furnace or The final melting and refining process was carried out in a converter.However, these known methods had the disadvantage of requiring a large amount of electrical and thermal energy, resulting in high costs.

In order to eliminate the drawbacks of the above-mentioned prior art and to meet the above-mentioned demand for energy saving, the present invention uses powdered or granular chromium oxide to enhance the This invention was made for the purpose of proposing a method for producing molten chromium metal, and its gist is that in the first invention, chromium ore or already pre-reduced chromium ore is Powdered or granular chromium oxide is injected into the molten iron in the smelting vessel using an oxidizing carrier gas, and at the same time, a carbonaceous material such as coal or coke is separately supplied into the molten iron to perform smelting. The feature is that a high chromium molten metal containing less than 40% of SiOr is produced.

In another invention, in accordance with the above characteristics, powdered or granular chromium oxide is injected as chromium ore, pre-reduced chromium ore, or a mixture of these and 7 lux. Furthermore, in the other two inventions, in addition to each of the above-mentioned features, refining is carried out by separately supplying a stirring gas into the molten metal. As a result, the Cr content is 4
The feature is that a high chromium molten metal having a content of less than 0% is produced.

The present invention will be described in detail below. The basic idea of the present invention is to add chromium ore oxide to molten iron and melt it under reduction to achieve a predetermined content, that is, 40% Cr content.
When melting a high-chromium molten metal of less than 20□→CO (fever)...(2)0+
The aim is to improve energy efficiency by using the combustion reaction O-+CO2 (exothermic) (3).

Therefore, in the present invention, in addition to the amount of solid carbonaceous materials such as coal and coke necessary for reducing Or, the necessary amount of carbonaceous materials for the above-mentioned combustion (in addition to added coke, [ %
In addition to preparing the above (2) and (including
3) A gas for causing the reaction of the formula: that is, oxygen or an oxidizing gas containing oxygen is supplied to the molten iron in the refining vessel. The method of supplying it is carried out by blowing it alone or as an oxidizing carrier gas for the above-mentioned chromium ore through a top blowing lance or a bottom blowing plane.

When chromium ore is used as a chromium source to be added to molten iron, it is necessary to increase the reaction interfacial area in order to ensure the rapid progress of the reduction reaction of N G r 20 a. Alternatively, powder or granular pre-reduced chromium ore that has been pre-reduced to some extent is used and is directly inhaled into the molten iron through an oxidizing carrier gas from a top-blowing lance or a bottom-blowing sluice.

In addition, the above chromium oxide ores include calcium carbonate (
0aCO8) and calcium hydroxide (Ca (OH)2)
Alternatively, a mixture of a sludge-forming agent such as calcium oxide (CaO) or calcium fluoride (CaF2) can also be used. The use of mixed chromium ore with this slag-forming agent
Cr2O3, MgO, and At108 in the chromium ore form a composition with a low melting point together with OaO, which advantageously acts to further promote the reduction of chromium oxide.

Oxygen or an oxidizing gas containing oxygen is used as the oxidizing carrier gas for injecting powdered or granular chromium oxide into the molten iron. ), 0. Since chromium is supplied to the spark point by the jet, the reaction has the advantage of proceeding well at high temperatures.

Further, in order to supply thermal energy through the exothermic reactions of the above equations (2) and (8), a carbonaceous material such as coal or coke is introduced. The carbonaceous material may also be fed into the furnace together with an oxidizing gas or a non-oxidizing gas through a top blowing lance or a bottom blowing tuyere.

In the case of the present invention, in addition to the above-mentioned configuration, it is convenient to introduce N2 or Ar gas as a stirring gas primarily through the bottom blowing tuyere in order to promote the reaction.

Next, examples of the present invention will be shown. In the examples, a converter furnace with a furnace capacity of 100 tons as shown in FIG. 1 was used.

In addition, the reference numeral 1 in the figure is the furnace body, 2 is the bottom blowing surface, - of which 2a is the protective gas pipe, 2b is the powder injection pipe, 3 is the top blowing lance, 4 is the slag, and 5 is the molten iron. .

Propane is normally flowed through the retained gas pipe 2a for cooling, and air, N, or a mixed fluid of 02+N2 mixed gas and coal powder is flowed from one powder injection pipe 2b.
02 or 0°10N2 from the other powder injection pipe 2b'
Mixed gas and chromium ore powder or chromium ore powder and CaO
Flow the mixed fluid with the powder. Another method is to inject normal refining gas from the bottom blowing tuyere 2, and add chromium ore powder or chromium ore powder and CaO powder to the 02 or 020 N2 mixed gas from the top blowing lance 3. There is also a method of refining by injecting coal into the furnace at the same time.

Furthermore, as a carrier gas used when blowing chromium ore powder or chromium ore powder and CaO powder, an oxidizing gas is used in either the top blowing lance or the bottom blowing layer, and a non-oxidizing gas is used in the other layer. Also, the oxidizing gas in the present invention is chromium ore powder or chromium ore powder and CaO
This belongs to one modification in which the powder is used as a carrier gas.

Example 1 70 tons of hot metal (0: 4.5%,
Si: 0.4%, pro. 02 Section) was charged. Hot metal temperature was 1300°010 bottom blowing tuyere 2
b' to aooooNm8 02 and 48t Or ore powder (T, Cr: 88.7%, T, Fe: 18.
5%, MFO: 9゜8chi, At208: 18゜64
%, P: 0.001%), and 10 tons of CaO powder was blown into it.
0 □ was injected from 10 bottom blowing tuyeres 2b to 7
00ONm” of N2 and 70t of coal (Q: 78.5
%, H: 4.49%, N: 1.89, O: 6
．． 14%, Ash: 8.54%).

It took 100 minutes during that time, and the temperature of the molten steel after the furnace was 1600"
o and c were 3.6%, and Or was 15.1%.

The yield of Cr in the molten steel was 94.2%.

British J.
35%, P: 0.018%) was charged. The hot metal temperature was 1280'O, and 8 tons of Or ore powder (composition is the same as in Example 1), 5 tons of CaO powder, and 400 ONm8 of N2 were blown into the 010 bottom blowing holes 2b'. Also, 2000ONI from the top blowing lance]]
802 and 2ff"t of Or ore powder and 5t of CaO powder were blown into the air. From the 10 bottom blowing tuyeres 2b, 3700
I blew ONm's 02. In addition, 70 tons of coal was divided into pieces and charged into the furnace from the furnace mouth. During that time, it was 95 minutes.
The temperature of molten steel after collapse is 3.4% for 162Q'O10, Or
was 14.9%. In addition, the slag composition is T, Or
: 2.9%, T, Fe: 1.1%, C1aO: 3
2.5%, SiO3: 1a, 2%, At208: 8
1.2chi, MNO: 15.2%. The Qr yield into molten steel was 93.9%.

Example 8 Hot metal (C: 4.5%, S
i: 0045 excellent, P: 0.016%) was charged. The hot metal temperature was 1310'O. 10 bottom-blown stitches 2b' to 8.000' ONm8 0 and 50t
Or ore powder (T, Cr: 8t7%, T, Fe:
18.5%, MgO: 4.8, At, 08: 1
3.64%, P: 0.001ch). Additionally, 2800 ONm of 02 was injected from the top blowing lance. 10 tons of CaO lumps were divided into 5 parts from the soil and introduced. 650ONm8 N2 from 10 bottom blowing tuyeres 2b
and 65 tons of coal (C: 78.5%, H: 4.49
%, N: 1°89%, O: 61.3%, Ash: 8
．． 54%) was injected. The time was 90 minutes, the temperature of the molten steel after the furnace was 1620℃, C was 3.8%, and Or was 15.
．． Also, the slag composition is T, Or = 2
．． 7%, T, Fe: 2.0%, OaO: 84.1%
, 5iOs: 14.2%, At208: 29.4%
, MfO: 16.8%. The yield of Or into the molten steel was 92.8%.Comparative example: 70 tons of hot metal (C: 4.4%, Si
: 0.25%, pro. 02%) was charged. The hot metal temperature was 1330'O. 26 from 10 feathers
I blew 02 of 00ONm8. 260 from top blow lance
I blew 02 of 0ONm8. 10 bottom blowing tuyeres 2b'
600ONm of N2 and 65t of coal (C near 8.
5 Chi, H: 4.49%, N: 1.8
9%, 0: 6.18 fissures, Ash: 8.
In addition, 50 tons of Or ore and (3a
010 tons of mixed pellets were divided into 10 times and charged from the furnace mouth, and it took 150 minutes for each time. The molten steel temperature after the furnace was 3.1% for 1640'010 and 13.7% for Or. The slag composition is T, Or! 7.9%, T, -F
e: 4.5%, OaO: 80.2%, 5in2:
12.5%, At208: 80.2%, Mflo:
It was 14.8%. Or yield in molten steel is 84
．． The results of 0% or more are shown in Table 1.0 Comparing the above examples and the 10 comparative examples, it is found that the present invention significantly increases the Or yield in molten steel. was confirmed.

As is clear from the above explanation, according to the present invention, a high-chromium molten metal can be produced using inexpensive raw materials (chromium ore, coal) and with less energy.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the hero of the present invention. 1... Furnace body 2... Bottom blowing tuyere 2a.
...Protective gas pipelines 2b, 2b'...Powder injection pipe 3...Lance 4...Slag 5...
Molten iron.

Claims (1)

[Claims] 1. Chromium ore or barge: At the same time, chromium ore powder and granular chromium oxide, which have already been pre-reduced, are injected into molten iron in a refining vessel with an oxidizing carrier gas, A method for producing a high chromium molten metal, which is characterized in that a high chromium molten metal with an Or content of less than 40% is produced by separately supplying carbonaceous materials such as coal or coke into the molten iron and performing five refining processes. & more The method according to claim 1, wherein the oxidizing carrier gas is oxygen or an oxidizing gas containing oxygen. & The method according to claim 1 or 2, characterized in that the chromium oxide is injected into the molten iron through a top 7° blowing lance or a bottom blowing tuyere. Table 1. Chromium ore or powder or granular chromium oxide, which has already been pre-reduced, is injected into the molten iron in the refining vessel using an oxidizing carrier gas, and at the same time, coal, coke, etc. are separately added to the molten iron. A method for producing a high chromium molten metal, characterized in that a high chromium molten metal having a Cr content of less than 40% is produced by supplying carbonaceous material and refining. A method according to the claims, characterized in that the oxidizing carrier gas is oxygen or an oxidizing gas containing oxygen. 6. The method according to claim 4, wherein the method is carried out through bottom blowing. Powdered or granular chromium oxide made of chromium ore or pre-reduced chromium ore is injected into the molten iron in the refining vessel using an oxidizing carrier gas, and at the same time, coal or coke is separately added to the molten iron. 1. A method for producing a high chromium molten metal, which comprises producing a high chromium molten metal having a carbonaceous material such as carbonaceous materials such as carbonaceous materials, and a Si-Or content of less than 40 parts. 8. At the same time, powdered or granular chromium oxide made of chromium ore, pre-reduced chromium ore, or a mixture of them and flux is injected into the molten iron in the refining vessel using an oxidizing carrier gas, By separately supplying carbonaceous materials such as coal or coke and stirring gas to the molten iron, the Or content can be reduced to 40%.
A method for producing a high chromium molten metal characterized by producing a high chromium molten metal with a content of less than 100%.