JPS6015562B2 - Production method of yellow phosphorus and mold additive for steelmaking - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing yellow phosphorus and a mold additive for steelmaking, and its purpose is to improve the conventional method for producing yellow phosphorus and at the same time to effectively utilize the slag produced in the process. This is what we aim to do.

Generally, yellow phosphorus is produced by reducing and melting a mixture of carbonaceous materials such as phosphate rock, silica stone, and coke in an electric phosphor furnace to collect the vaporized yellow phosphorus. Slag is produced as a by-product.

This slag is often used as a soil conditioner in Japan because it is a weakly basic calcium oxalate containing soluble phosphoric acid, calcium, and silica. Conventionally, in the production of such yellow phosphorus, an improvement method has been known in which an aluminum-containing substance is added to produce high alumina slag as a by-product that can be used as slag cement (1952, TENNSSEE VALLE
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nginee phantom ngReport M. 3).

However, this method has not been successful in Japan due to its low industrial capacity. Furthermore, a conventional method of adding a solid acid is known for the purpose of reducing energy costs (Tsubaki Kosho No. 44-31929). However, this method has not been applied for the same reasons as mentioned above, and in either case, the amount of slag increases and the addition of aluminum reduces the fertilizer effect, so its industrial applicability is definitely not effective. Otherwise, it may even be industrially inferior to conventional methods. The manufacturing method of yellow phosphorus is a typical energy-consuming industry that uses a significant amount of electricity, so we are working on technological innovations that save as much energy as possible, and at the same time, we are making effective use of the large amount of by-product slag with high added value. If we don't solve the problem, we are in a very difficult environment for our survival.

Under these circumstances, the present inventors first discovered that amorphous basic calcium fluorosilicate powder, which is a by-product of granulated slag, has excellent properties as a mold additive for steelmaking. This discovery paved the way for the use of the slag as an industrially effective material (Special Report No. 53-183549).

On the other hand, in recent years, various technologies have been developed in the steel industry with the aim of increasing productivity and improving quality, one of which is the shift to high-speed operation in steel casting, especially continuous casting.

In view of this fact, the present inventors continued intensive research to further improve the applicability of conventional slag.
The present invention was completed by discovering a rational method in relation to the method for producing yellow phosphorus.

That is, the present invention provides a method for producing yellow phosphorus by heating and melting a mixture of raw materials such as phosphate rock, silica stone, and coke in an electric furnace to recover yellow phosphorus, and pulverizing the created slag. Adding an aluminum-containing substance and a fluorine-containing substance to the raw material mixture to a height a0・ySi02・zR2
Q・wF (where x is 1.05 to 1.3, y is 1.0,
z=0.03~0.2, w is 0.2~0.8, R20
3 represents AI203 + Fe203) The present invention relates to a method for producing yellow phosphorus and a mold additive for steelmaking, characterized in that the additive is added so as to have a molar composition of (3 represents AI203 + Fe203). Since the molar composition of the slag-forming components in the raw material mixture and the molar composition of the produced slag are substantially the same, the present invention will be described hereinafter simply using the term "slag". That is,
Fluosilicate-containing calcium, which is the slag created in the conventional yellow phosphorus production method, basically has material properties as a mold additive for steelmaking, but it varies depending on the type of phosphate ore, manufacturing conditions, etc. Not only was it not possible to obtain a product of constant quality, but the slag as it was was insufficient to meet the required characteristics of the additive.

According to numerous experiments conducted by the present inventors, slag with the above-mentioned specific composition, which is a conventional slag based on calcium fluorosilicate with a slightly increased content of alumina and fluorine, is suitable for steelmaking. It was found to be an excellent mold additive.

Therefore, in order to obtain such slag, in the conventional production of yellow phosphorus, an alumina-containing substance and a fluorine-containing substance are added as a slag conditioner to a raw material mixture to adjust the formulation, thereby obtaining high quality and stable composition of the additive. This product was successfully manufactured in a rational manner. This has the secondary advantage that the desired product can be co-produced by saving energy without reducing the yield of yellow phosphorus due to the simultaneous lowering of the melting point of the slag.

Due to the nature of the raw material mixture, the alumina-containing substance to be added is
3. There is no need to specifically limit the material as long as it is a Yama203-Si02-based material or a Ca○-N203-Si02-based material.

Such substances include, for example, feldspar, pearlite, alumina cement, alumite, bauxite, chardite, sillimanite, zeolite, kaolin, etc., and one or more of them may be used. On the other hand, examples of fluorine-containing substances include crabite, cryolite, aluminum fluoride, and the like.

Fluorine is generally originally contained in phosphate ore, but the present invention is characterized by the fact that it is actively added together with alumina, which significantly lowers the melting point of slag and increases the gives viscosity and surface tension. This is not only desirable for its operation, but also required from the standpoint of utilization of the created slag. The amount of these additions depends on the phosphate rock, other raw material circumstances,
Although it varies depending on the melting point, viscosity of slag, and the applicability of slag as a mold additive for steelmaking, at least the slag composition has a molar ratio of a0 to i02 and zR203.
・wF (in the formula, or 1.05 to 1.3 y is 1.u z
is 0.03-0.2, w is 0.2-0.8, R is mountain 2
It is necessary to add the above-mentioned regulator to the raw material mixture so that the amount is within the range of 030Fe2Q (Fe2Q is substantially an impurity). In the process of recovering yellow phosphorus by heating and melting a raw material mixture of carbonaceous materials such as phosphate rock, silica stone, and coke in an electric furnace, the inside of the electric furnace is in a strongly reducing atmosphere, so that Pe○, Fe2Q, Fe3
Iron oxides such as 04 are reduced to metallic iron. Due to the density difference between molten slag and molten iron, the iron sinks to the bottom of the furnace, and when the slag is taken out of the furnace, the slag and iron are tapped separately. Fe2Q in the slag is 0.2 to 2.0%, usually 0.4% or less. From the above, in the present invention, phosphate bandedite can also be advantageously used as another raw material. In the case of the conventional method, it is limited to abatite-type phosphate rock, and the abatite-type phosphate rock has virtually no use value.

That is, the Sosei slag has been used as a fertilizer, but in this case, when the AI2Q content is high, there are many problems such as reducing the available phosphoric acid in the soil as a raw material for phosphoric acid fertilizer. However, in the method according to the present invention, since phosphorus and alumina can be used advantageously, they can be used as rather suitable raw materials, opening the way to their effective use as raw materials for producing yellowish phosphorus. The slag produced by the method of the present invention is itself an improved additive that can be used as an additive for continuous casting in steelmaking, but if necessary, it may be preferable to contain an alkaline component such as Na20. .

In such a case, if alkaline content is added during the production of yellow phosphorus, it will lead to a decrease in the yield of yellow phosphorus or contamination, so even if added, the amount should not exceed about 2% by weight in the raw material. Therefore,
When an alkaline content is required, it is of course possible to mix other alkaline agents when using the slag as an additive, but it is also possible to add the desired amount of alkaline agent to the molten slag discharged during the production of yellow phosphorus. It is preferable to add alkali components to form a uniform composition. Such alkaline agents include, for example, soda ash, kudzu glass, alkali silicate, etc. Glassy agents are particularly preferred for operational reasons. In this case, the amount of the alkaline agent added is at most 0.4 mole as M20 (M represents Na or K) per mole of Si02 in the slag. Any such slag must be amorphous and granulated by quenching with water.

Slowly cooled crystalline slag of any composition is not suitable as a molding additive. This slag is further ground to a desired particle size distribution suitable for the additive.
In addition, the alkali agent is granulated slag powder, amorphous glass powder,
For example, soda silicate glass and soda quartz glass powder may be mixed. Thus, by the method of the present invention, it is possible to produce yellow phosphorus in an energy-saving manner, and at the same time, it is possible to utilize the created slag as a suitable additive for casting. That is, the additive must have a constant viscosity and surface tension at a certain temperature during casting, and unlike static agglomeration such as top pouring or bottom column agglomeration, continuous casting requires constant viscosity and surface tension. It must always have stable viscosity and surface tension in a dynamic equilibrium state due to changes in steel type and casting speed, and must have properties as an additive. Therefore, such requirements are extremely demanding both physically and chemically, and the slag according to the present invention substantially meets these requirements.

For example, in terms of compositional uniformity, it can be used as a single-layer additive in which all components exist uniformly in the form of glass. This means that when used as an additive, it melts quickly at a constant melting temperature, and since its melting composition is constant, there is no difference in melting point. The surface is always covered with molten liquid in a stable state.

Therefore, it has excellent followability in high-speed casting, and particularly satisfies the demand for followability in continuous casting. Thus, the granulated slag powder obtained by the method of the present invention can be used as a base material and mixed with a small amount of carbonaceous material such as coke and, if necessary, a small amount of alkaline agent, by a conventional method to produce steel in the final use form. In this case, the above preparation can be granulated with a binder such as water or sodium silicate to the desired particle size and dried to be used as a suitable casting additive.

The present invention will be explained below with reference to Examples and Comparative Examples.

Parts or percentages in the text are parts by weight or percentages by weight unless otherwise specified. Example 1 The composition shown in Table 1 was 100 parts of phosphate rock, 268 parts of quartzite, 195 parts of coke, 18 parts of crabite, and 354 parts of anorthite.
15% of yellow phosphorus is mixed and melted in an electric furnace for producing phosphorus.
I got 7 copies.

On the other hand, a part of the by-product slag was pulverized as it was, and 100 parts of the molten slag and 41 parts of sodium silicate glass were added to it, uniformly melted, and then pulverized, as shown in Table 2. Slag A and slag B shown below were obtained.

Note that the electric power required to obtain 157 parts of yellow phosphorus at this time was 2100 KWH. For comparison, 100 parts of phosphate rock, 486 parts of silica stone, and 195 parts of coke with the same composition were mixed and melted in the same manner using the conventional general manufacturing method to obtain 1 mottled part of yellow phosphorus; Granulated slag C
A comparative example was obtained. The power consumption at this time was 2354 KWH, and the former was able to significantly reduce energy costs. Next, each slag obtained above (second
Table) is pulverized to 100 mesh or less with a tube mill, and then the raw material composition shown in Table 3 is mixed with a V-type mixer, granulated into 1 to 2 ribs using water, and dried to form additives for continuous casting. did.

Note that this blending composition (molar ratio) is the second highest, excluding coke.
It has the same composition as B slag in the table. Table 1 Table 2 Note: C is a comparative example Table 3 Note) Sodium silicate is the same as in Table 1.

C is a comparative example. These additives are added at 0.5k9/t・
The results shown in Table 4 were obtained when continuous casting of low carbon aluminum killed steel was performed using the same proportions as steel.

4th table ■: Table of 1 item after cold scarf Note ■: Percentage of surface illusion products found in the product Note ■: C
is a comparison.

Example 2 150 parts of phosphate band ore shown in Table 5, 85 parts of phosphate rock shown in Table 1, 45 parts of silica, 190 parts of coke,
14 parts of fluorspar was blended and melted in a fin furnace for producing yellow phosphorus to obtain 15 parts of yellow phosphorus.

The electric power required for this was 215 WH, making it possible to significantly reduce the electric power cost compared to the conventional method. On the other hand, wealth. A part of the raw slag was pulverized as it was, and another part of the molten material was pulverized after adding sodium sulfate glass at a ratio of 41 parts per 100 parts of the slag to uniformly melt the slag.
The analytical value of the slag pulverized as it is is A' shown in Table 6, and the analytical value of the slag to which sodium oxalic acid has been added is B' shown in Table 6. Using these, the same procedure as in Example 1 was carried out. The additives for continuous casting were prepared by blending. As a result of a continuous casting experiment using each additive under the same conditions as Example 1, there was almost no significant difference from A and B listed in Table 4, and good casting results were obtained similarly to the above examples. was completed. Table 5 Phosphate band ore analysis values Table 6 Slag composition (weight*)

Claims (1)

[Claims] 1. Yellow phosphorus is produced by heating and melting a raw material mixture of carbonaceous materials such as phosphate rock, silica stone, and coke in an electric furnace to recover yellow phosphorus, and by pulverizing slag as a by-product. In the method, xCaO・ySiO_2・zR_2O_3・
wF (wherein, X is 1.05 to 1.3, y is 1.0, z is 0.03 to 0.2, w is 0.2 to 0.8, and R_2O_3
represents Al_2O_3+Fe_2O_3). 2. The method for producing yellow phosphorus and a mold additive for steelmaking according to claim 1, which comprises adding an alkaline agent to the molten slag produced as a by-product and then pulverizing it. 3. The method for producing yellow phosphorus and a mold additive for steel manufacturing according to claim 1, which comprises adding an amorphous alkaline agent to the granulated slag produced as a by-product.