JPS59113157A - Method for refining iron-chromium alloy - Google Patents

Abstract

PURPOSE:To obtain an Fe-Cr alloy using inexpensive starting materials while saving energy by directly blowing powder or granules of chrome ore or prereduced chrome ore into molten iron with a carrier gas. CONSTITUTION:Powdery or granular chromium oxide made of chrome ore, prereduced chrome ore or a mixture of the ore with a flux is prepd. The chromium oxide is blown into molten iron with a carrier gas, and at the same time, a carbonaceous material such as coal or coke is fed to carry out refining. Oxygen, an oxidative gas contg. oxygen, an inert gas or a nonoxidative gas such as nitrogen is used as said carrier gas. An Fe-Cr alloy is obtd. using inexpensive starting materials while saving energy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for smelting iron-chromium alloys, and in particular to a method for melting iron-chromium alloys, in particular, adding 9 particles of chromium oxide 15 to the molten iron in a converter or similar refining vessel containing the molten iron. A method suitable for producing Hue chromium having an Or content of 40% or more by injection and refining will be described.

In line with the recent trend of lowering the grade of ores and turning them into fine minerals, the general production of ferroalloys involves first pre-processing and agglomerating the V0 powder and one granular ore, and then using electric furnaces and The final melting and refining process was carried out in a converter. However, these known methods have the drawback of requiring a large amount of electrical and thermal energy, resulting in high costs.

The purpose of the present invention is to propose a technique for simply melting and refining the above-mentioned conventional ferroalloys, particularly iron-chromium alloys, using powdered nine-grain chromium oxide. The gist of its composition is that a powder-like chromium oxide consisting of chromium ore, pre-reduced 111 stones of chromite, or a mixture of these and 7 lux is added to molten iron in a smelting vessel using a carrier gas. At the same time as the molten iron is injected, a carbonaceous material such as coal or coke is separately supplied to the molten iron for refining, thereby producing an iron-chromium alloy having an Or content of 40'% or more; It is in. The details of the configuration will be explained below.

The basic concept of the present invention is to add chromium ore oxide to molten iron, reduce and melt it, and then
When melting 7erochrome with an r content of 40% or more, the following endothermic reduction reaction of chromium ore; Or, 08+ 30 → flr + 800↑ (endothermic)
To compensate for the heat absorption associated with song/ken 1), C+''”A O2→CO (heat generation)...
・・・・・・・・・・・・・・・・・・(2) C+0 →o
The aim is to improve energy efficiency by causing the combustion reaction to take place (heat generation) . . . curvature value 8).

To this end, the present invention provides, in addition to the amount of solid carbonaceous materials such as coal and coke necessary for the reduction of Or, the amount of carbonaceous materials necessary for the above-mentioned combustion (in addition to the added coke, [%] C]
In addition to preparing the above (2)? (
8) Ga)′ for causing the reaction of formula.

In other words, oxygen or an oxidizing gas containing oxygen is supplied to the molten iron in the refining vessel. The chromium ore powder is supplied either singly or as a carrier gas for the chromium ore powder through a top blowing lance or a bottom blowing tuyere.

When chromium ore is used as a chromium source to be added to molten iron, it is necessary to increase the reaction interface area in order to ensure that the reduction reaction of Or, 08 proceeds quickly. Using 9 grains of pre-reduced chromium ore/stone that has been pre-reduced to some extent, this is directly injected into molten iron from a top-blowing lance or a bottom-blowing lance via a carrier gas.

Furthermore, slag-forming agents such as calcium carbonate (OaOO), calcium hydroxide (Oa(OH), etc.), calcium oxide (Oak), and calcium fluoride (OaF s ) are added to the above-mentioned chromium oxide ore. It is best to use a mixture.

The use of mixed chromium ore with this slag-forming agent allows c3rsOB*'go and A/, 08 in chromium ore to be OaO
Together with this, a composition with a low melting point is formed, which works advantageously to further promote the reduction of chromium oxide.

The carrier gas used to inject the granular chromium oxide powder into the molten iron may be oxygen or an oxidizing gas containing oxygen, or may be an inert gas or non-oxidizing gas such as nitrogen. The purpose of the former is to provide an oxygen source to guide the exothermic reaction l of formula (2) and (8) above in conjunction with the transportation of chromium-'...(4) chloride powder, and 0
Since chromium is supplied to the fire point by the two jets, the reaction has the advantage of proceeding well at high temperatures, and although the latter is simply a carrier gas, it is the oxygen source for the necessary reduction and refining. Separately, it falls under the type of supply using top-blown lances or bottom-blown slats.

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

In the case of the present invention, in addition to the above-mentioned configuration, in order to promote the reaction, N or Ar gas as a stirring gas is introduced mainly from the bottom blowing surface, which results in a better reaction.

Next, regarding the embodiment of this invention, 1 volume 10 shown in FIG.
An example of refining using a 0t converter will be explained. In addition, the reference numeral l in the figure is a furnace body, 2 is a bottom blowing tuyere, of which 2a is a protective gas pipe, 2b is a powder blowing 2'' pipe, 3 is a top blowing lance, 4 is a slag, and 5 is a 1. It is molten iron.

Propane is normally flowed through the protective gas pipe 2a for cooling, and air, N2 or 02+N, or a mixed fluid of mixed gas and coal powder is flowed through one of the powder injection pipes 2b.
A mixed fluid of 02+N, mixed gas, and chromium ore powder is flowed from the other powder injection pipe 2b'. Another method is
Normal refining gas is injected from the bottom blowing tuyere 2, and chromium ore powder is injected into the O, O, + N2 mixed gas from the top blowing lance 8 to a distance of 1 m, and at the same time coal is injected from the furnace mouth. There is also a method of smelting it by inputting it.

Example 1 Molten iron (0/
4.4%, 8110.3%, Plo, 017%) and 80
chromium ore powder (T-Or/, 18.7%, T-F
6/18.5%.

MgO/9.8%, A! 208/18.6%, Pl
o, 001%) and further 15t of CaO as a carrier gas, inject N, 101,000ON, and 72,000Nm from the remaining 10 powder injection holes □□(2b)”
+7) O, was injected.

On the other hand, 95,000 Nm'' of 0° was blown from the top blowing lance, and 80 tons of chromium ore was added from the furnace mouth.

Example 2 In the above converter, 1820°C molten iron (0/
This is an example in which the entire amount (160 tons) of chromium ore was supplied by bottom blowing to the molten iron that was being melted by charging 4.5%, 5i, 10.4%, Plo, 022%).

Example 3 In this example, molten iron ((3/4.5%, 5i70.25%, Plo,
The chromium ore powder and CaO powder, which are supplied from the bottom blowhole, are charged to the molten iron that is being melted.
This is a method in which O8 is used instead of .

The results of the above-mentioned examples are shown in Table-1.

271 As is clear from the above description, according to the present invention, an iron-chromium alloy can be produced using inexpensive raw materials (chromium ore, coal) and with less energy.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment 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 patent applicant Kawasaki Steel Corporation 10) Figure 1 273-

Claims (1)

[Claims] 1. Chromium ore or already pre-reduced chromium ore,
Alternatively, two grains of chromium oxide powder consisting of a mixture of these and 7 lux are injected into the molten iron in the refining vessel using a carrier gas, and at the same time, a carbonaceous material such as coal or coke is separately supplied into the molten iron. A method for producing an iron-chromium alloy, the method comprising producing an iron-based alloy having a Qr content of 40% or more by refining the iron-chromium alloy. The method according to claim 1, wherein the carrier gas is oxygen or an oxidizing gas containing oxygen. & The method according to claim 1, wherein the carrier gas is an inert gas or a non-grading gas using nitrogen. 82. The method according to any one of claims 1 to 81, characterized in that the injection of the chromium oxide into the molten iron is carried out through a top blowing lance or a bottom blowing groove. Mr. Chromium magnet or pre-reduced chromium ore,
Alternatively, 9 grains of chromium oxide powder consisting of a mixture of these and 7 lux is injected into the molten iron in the refining vessel using a carrier gas, and at the same time, separately into the molten iron,
A method for producing an iron-chromium alloy, characterized in that an iron-chromium alloy having an Or content of 40% or more is produced by supplying a carbonaceous material such as coal or coke and a stirring gas for refining.