JPS6043884B2 - Desulfurization agent - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in desulfurization agents made of soda ash.

Conventionally, out-of-furnace desulfurization of hot metal using soda ash has been carried out by placing soda ash in a pouring ladle, injecting hot metal, blowing in No gas, etc., and stirring the soda ash and hot metal. This desulfurization reaction is thought to proceed according to the following equation.

Na2co3■Na2o+co2 Na2O+[S]+[C]■Na2SfC0 This desulfurization reaction proceeds in an oxidizing atmosphere, and Si and Mn in the hot metal are removed by oxidation at the same time as desulfurization.

However, there is a problem in that desulfurization efficiency is insufficient in an oxidizing atmosphere, and it is preferable to remove Si in a converter because it becomes a heat source, and Si is not desired to be removed during desulfurization.
The present invention aims to solve this problem, and provides a desulfurization agent characterized by adding a predetermined amount of carbonaceous material such as coke powder to soda ash to form a reducing atmosphere during desulfurization treatment. It is something to do.

The desulfurization agent of the present invention is made by adding a carbonaceous material to soda ash, and contains Na.

The number of moles of CO3 and the number of moles of C in the carbonaceous material are 113~
It was added at a ratio of 3. The desulfurization agent of the present invention forms a reducing atmosphere in hot metal as shown in the following formula, increases desulfurization efficiency, and suppresses consumption of [51] in hot metal. Na2co3+c→Na2O+2CO As described above, under a reducing atmosphere, the activities of JCS] and [C] in hot metal increase, and the desulfurization efficiency increases.

As can be easily understood from the above equation, when the number of moles of C in the carbonaceous material is less than 113 of the number of moles of Na2CO3, a sufficient reducing atmosphere cannot be obtained. On the other hand, even if the carbonaceous material is added in an amount in which the above-mentioned molar ratio exceeds 3, no particular effect will be obtained and it will be uneconomical, and furthermore, there is a risk of increased contamination of impurities, especially S, in the carbonaceous material. be. The carbonaceous material may be any material mainly composed of carbon that reacts with soda ash to generate CO when mixed with hot metal, and coke powder is particularly preferred for practical purposes. As described above, the desulfurization agent of the present invention is intended to increase the desulfurization rate by forming a reducing atmosphere during desulfurization treatment. Therefore, adding a component that inhibits the formation of a reducing atmosphere, such as iron oxide, to the desulfurizing agent of the present invention would deviate from the spirit of the present invention. Also,
The desulfurization agent of the present invention uses soda ash and coke powder as a binder.
Preferably, it is molded into a pellet having a diameter of 0 to 50 φ.
As the binder, water or an oil-based binder such as kerosene or light oil can be used.

When using an oil-based binder, the C in the oil-based binder also reacts with soda ash, so the sum of the moles in the coke powder and binder is N.
The number of moles of a2cO3 is preferably in the range of 113 to 3. Examples of the present invention will be described below. Example 10 parts by weight of soda ash and 1 part by weight of coke powder were caked with 5 parts by weight of kerosene to produce pellets of 27φ.

On the other hand, as a comparative example, soda ash single pellets (30φ
) was prepared. These desulfurization agents were placed in a pouring ladle, and hot metal having the components shown in Table 1 was poured into the ladle, followed by N2 injection.

The results are shown in Table 1.

As is clear from the results in Table 1, in the case of the desulfurization agent of the present invention, the average desulfurization rate was about 61.5% at a basic unit of about 2.9k/T, and in the case of the comparison, it was about 32.7%. Almost double the desulfurization efficiency has been achieved.

Furthermore, the reduction in hot metal [Si] is also at a significantly lower level than in the comparative example.

Claims (1)

[Claims] 1 Carbonaceous material in soda ash, Na_2C in soda ash
A desulfurization agent characterized by being made by mixing O_3 and C in a carbonaceous material in a molar ratio of 1/3 to 3, and forming a reducing atmosphere during desulfurization treatment. 2. The desulfurization agent according to claim 1, wherein the carbonaceous material is coke powder, and soda ash and coke powder are molded into pellets with a binder. 3. The desulfurization agent according to claim 2, wherein the molar ratio of Na_2CO_3 to C contained in both the coke powder and the binder is in the range of 1/3 to 3.