JPS5861242A - Manufacture of high purity ferrosilicon containing calcium and aluminum - Google Patents

Abstract

PURPOSE:To manufacture high purity ferrosilicon for reforming steel, by adding Ca to molten ferrosilicon to reduce Al2O3 in the molten metal and adding Al to prepare iron contg. Si, Al, Ca and nonmetallic inclusions having a specified composition. CONSTITUTION:Ca is added to molten ferrosilicon consisting of 10-99.5% Si and the balance chiefly Fe to reduce Al2O3 contained in the molten metal by deoxidation, and a necessary amount of Al is added. Thus, high purity ferrosilicon consisting of 10-99.5% Si, 0.05-4% Al, <=4% Ca, <=0.25% nonmetallic inclusions and the balance essentially Fe is manufactured. The nonmetallic inclusions has a composition consisting of <=15% Al2O3, <=80% CaO, <=5% FeO and the balance SiO2 with inevitable impurities. This high purity ferrosilicon is suitable for use in the manufacture of silicon steel with high workability or tough cast iron.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing high-purity silicon iron containing calcium and aluminum for use in modifying steel. The present invention relates to a method for producing high-purity silicon iron for use.

As the seven inventors of the present invention, Tokuko Shotei Co., Ltd.
/'II exceeds 81 ss %, and the sum of this and Fe is more than jS-, and Ca exceeds /, /- and j-
less than.

The composition has a composition in which the total amount of alkaline earth metals other than Ca is s% or less, the Ca remains contained by reduction of the calcareous raw material, and the oxygen content is θ, θ cos% or less by this reduction, and the remainder is Fe. and Al as an unavoidable impurity.
We proposed a silicon iron for steel refining and tough cast iron containing carbon, etc., and received the patent number! 4021. A patent was registered in the / issue, and furthermore, according to Japanese Patent Publication No. 39-3272, it contains Fe 9θ or less and Si 10 to 29%, Ca4 (- or less,
kllo - t below.

Ca in the range of Ca (1) + AI (%) ≧ 3.0
Contains AI and 0.0 silicic acid or silicate! −
below.

We proposed a spheroidized ink lead alloy for the production of spheroidal graphite cast iron, which is characterized by containing other unavoidable impurities, or rat pig iron, which partially contains spheroidal graphite, and patent No. 74t1! rg
A patent was registered under No.g.

As can be seen from the above-mentioned invention, if nonmetallic inclusions are contained in ferrosilicon, it often interferes with the modification of steel, so ferrosilicon with as few nonmetallic inclusions as possible is required. For example, /? Issued in the Federal Republic of Nbiyet in February 1st, 2015
On page 199, a mixture of iron ore, limestone, 9 quartz, etc. is added to a molten 7S st ferrosilicon, and the nonmetallic inclusions in the molten metal are turned into slag. The manufacturing method is known.

However, when ordinary 7-erosilicon or ferrosilicon with few nonmetallic inclusions is used to manufacture electromagnetic silicon steel sheets, if it contains more than bIJ, s-, it becomes impossible to cool it, and It is known that when used in manufacturing, it cannot exhibit sufficiently satisfactory toughness.

The object of the present invention is to provide a novel method for producing high-purity ferrosilicon that eliminates and improves the drawbacks of ordinary 7-erosilicon or the known ferrosilicon. The above object can be achieved by providing a method.

As a result of intensive research into what is attributable to the above-mentioned drawbacks of the known ferrosilicon, not to mention ordinary ferrosilicon, the inventor found that even in the known ferrosilicon, the inclusion of non-metallic inclusions was found. The present invention was completed based on the new finding that, although the amount is extremely small, if the composition of the nonmetallic inclusions is inappropriate, improvement in the workability of steel or the toughness of cast iron is inhibited. I had come to the point of doing so.

On the 9th page of the above 5 tax in Er+glish, the total amount of nonmetallic inclusions and their chemical composition in 75% ferrosilicon subjected to standard 7s% ferrosilicon and aluminum removal treatment are listed as shown in Table 1 below. No.
7 Table Notes A, B: Standard Alloy C: Smelted in a ladle in a mixture of 1 iron ore, 1 limestone, and 0 quartz. According to Table 1 above, standard 7g% ferrosilicon is smelted with silicate-limestone slag in an acidic furnace at
'4 AI and 0. Contains about t −/, −1 nonmetallic inclusions, and the nonmetallic inclusions are 17 to −〇, 2−
The degree of Achi03 and 73 to 6-810. It is clear that aluminum silicate is the main ingredient. Furthermore, by subjecting the standard j-7 erosilicon to the slag treatment according to 07-3 and D described in the notes, the Al content can be reduced to 0.0.
The extremely low pressure of /d1 is reduced to a small value, and the total amount of nonmetallic inclusions is /, /9 *0. It can be seen that the number has decreased to 41-. However, even if the slag treatment by C2-5 or D is applied to the molten ferrosilicon, although the total amount of nonmetallic inclusions decreases according to each treatment, The composition of aluminum silicate in the remaining nonmetallic inclusions does not change significantly; for example, in the case of D treatment, Anyu is 0.7-0 before treatment, and after treatment, Anyu is #4 (arrogant). It can be seen that there is only a slight decrease.In this case, S before and after treatment
ToOyu is 3.1%, 7g, and o*, respectively. In other words, in the case of conventional high-purity FEP silicon with reduced non-metallic inclusions, the Kl content therein is 0.9%, as described in 5ta1 above, for example. Although the total amount of nonmetallic inclusions is very small at 0.2% in DI, the main component of the nonmetallic inclusions is aluminum silicate, which is composed of more than 100% of aluminum. That is clear.

According to the present invention, the content of nonmetallic inclusions in the known 7-erosilicon is 0.2391 or less, and the component composition of the nonmetallic inclusions is not more than AI, O, ts %.

Ca010Ill or less, Feor% or less, the balance is substantial) (We can provide a method for producing 7Erosilicon, which is SiO2, and according to 7Erosilicon, it is conventionally thought that cold rolling is impossible. !-A silicon steel plate containing the above can be easily produced, and various properties can be improved.

The non-metallic inclusions of 7-erosilicon of the present invention include, for example, Fe.
If O is excluded < Az, O, -CaO-810, o y elemental system phase diagram, the composition is within the range of the component composition indicated by diagonal lines in the diagram.

Next, a method for manufacturing high-purity ferrosilicon according to the present invention will be explained.

By a previously known method, the non-metallic inclusions in the ordinary ferrosilicon hot water are reduced to approximately 0.2 s (lb) or less, and Ca or an alloy containing Ca as a main component is added to the molten metal. Aluminum in the non-metallic inclusions; Al, O, constituting the ram silicate is reduced with C1 to form AI to reduce Al and O0. The dirosilicon of the present invention can be produced by adding the metal A/ in such a manner that the non-metallic inclusions are reduced by θ, co It is not necessary to keep it below j-, and it is sufficient that the content of nonmetallic inclusions in ferrosilicon and the component composition range can be made to match those of the present invention by the reduction treatment with Ca.

According to the present invention, first, Ca is used for AJ, 0. If Al is added first without performing an operation to reduce silicate, reduction of silicate will occur with Al, and 0. is generated, then Ca
Even if it is reduced with , it is not possible to produce the high-purity silicon iron of the present invention at full heat.

According to the present invention, by various means C & ? However, at the melting temperature of 7erosilicon, it is highly volatile and medium
It is important to charge ferrosilicon into the molten metal as quickly as possible and deep into the molten metal to effectively cause the catalytic reduction reaction between gaseous C& and klA. In addition, Ca or C invented by the present inventor and described in Mourning Patent No. tstsqt
The reduction reaction can be carried out most advantageously by the method of reduction using a linear cladding material having a-alloy as the core material.

The AI-O, -Sio-based inclusions before Oh addition are C
When it is reduced by & and changed to OaO-SiO inclusions, the condensation temperature decreases, they separate and float, and the deoxidizing reaction progresses, but the reaction rate 9 The reaction limit depends on the molten metal temperature, holding time, and amount of addition. It will be decided.

According to the present invention, when manufacturing ferrosilicon for silicon steel sheets, it is desirable that the rjkl content be low, so for example, 0.1% or less is added. In addition, when manufacturing ferrosilicon for strong cast iron, in order to improve the inoculation effect/~
By adding metal Al to the extent of flathead, the kl in the product is reduced to 3s.
The reason why the component composition is limited in the present invention will be explained below.

If there is less than St Fi10, the deoxidizing power will be extremely low.
And it is not economical to add as an alloy component of 81. On the other hand, if S1 is more than tq, sq4, the manufacturing cost is high and it is uneconomical to use.
It is necessary to use it within a range of 0.000000000000000000000000000000000000000000000000000000000000000000000000000100.00.01.

If Al is less than O1θr%, it is difficult to industrially produce it at low cost, while if it is more than lI, it is unnecessary and uneconomical, so AI should be within the range of o, or -da. There is a need to.

Since it is difficult to industrially manufacture a product with a Ca value higher than ↓, it is necessary to reduce the Ca value to less than ↓.

If the content of nonmetallic inclusions is more than O, cos%, for example, S
i J,! Since it is not possible to improve the workability of silicon steel with r of 4 or more, it is necessary to reduce θ to 25 or less.

If the amount of AI, O, in nonmetallic inclusions is more than 13, SIJ
, ! - Since the workability of the above silicon steels is not improved, AI
,0. must be less than /j-.

Since it is industrially impossible to increase the amount of CaO in the nonmetallic inclusions by more than 10 fb, the amount of CaO is set to be less than 10 fb.

If FeO is more than s%, the cold workability of silicon steel of 3.5- or more will not be improved, so it is necessary to make FeO less than SIs.

Next, the present invention will be explained with reference to examples.

Example 1 Approximately 1000 kg of YZ F4 Si molten silicon was charged into a 1-ton ladle in an electric furnace with an open L-set. Next, Oa-Si powder was filled, and a calcium φ silicide wire rod with a diameter of 9 was placed in the molten metal at trioC. rO”/
Addition was made at a feed rate of min. After the addition was completed, the metal Aj was heated to 11110°C for 3 minutes. - one addition was made. The composition of the silicon iron thus produced was 51to, z%.
, AI co, 12%, 0 & 0.4r%, non-metallic inclusions 0.7j 11 and A6, 0.4.2r%, (3
aO and others were 30.5-.

When this ferrosilicon was used for steel modification, very good results were obtained.

Example 2 Approximately 10θo kg of molten silicon of 7 qs tl St was charged into a ladle in an open type electric furnace with one L set. Next, a calcium wire rod with a diameter of ttm filled with metal Ca was added to the molten metal at 1310°C at a feeding rate of 00 cm, and after addition, it was left to stand for S minutes / 4t at 70°C.
0. A was added. The composition of the thus obtained 7erosilicon is Si72. ! r%, Alθ, s%, Gh/, 25-1 Nonmetallic inclusions 0. ///
-, and the component composition of the nonmetallic inclusions is Sin, 4I1
．． Light%, AI, O, j, Jf-, GaO and other J co,
It was tl. When this ferrosilicon was used for steel modification, very good results were obtained.

Comparative Example About 1000 kll of molten ferrosilicon melted in the same manner as in Example 1 was charged into a 1-ton ladle. Then metal Al
-After 9 hours of addition, a piece of calcium wire of t diameter filled with metal Oa was cooled/mi into the molten metal of tztO'C.
The component composition of the thus obtained ferrosilicon is S1, z-, *1i, and 1i.

Oa O,011G, nonmetallic inclusions 0.1! -, the composition of the nonmetallic inclusions is 5 inJtz, s -,
kl, O, so, sz*F・OJ, z, the remainder is mainly OaO. When this ferrosilicon was used for modifying steel, it was not sufficiently effective.

[Brief explanation of the drawing]

The figure is a J element phase diagram of AIJO, -CaO-Sin. Patent applicant: Metal Research Co., Ltd. Resilon patent attorney Mura 1) Politics

Claims (1)

[Claims] L 811θ ~ deq, z %, A contained in the molten metal by adding Oa to the silicon-iron molten metal, the remainder of which is mainly Fe.
J, 0. St to ~99., which is characterized by adding a required amount of AJ after deoxidizing treatment to reduce . ! --k
IO-01-1'74 e Oth l The following non-metallic inclusions are included, and the remainder is substantially F. - Below,
A method for producing high-purity silicon iron consisting of ChOtOf4 or less, FeOj% or less, and the balance mainly consisting of SiO and unavoidable impurities.