From many years of production practice, ice crystal powder is indispensable. It plays a certain role in reducing subcutaneous pores, slag inclusion and spheroidization recession. If the purchased cryolite powder did not enter the factory in time, it was stopped for four consecutive months. As a result, due to the high viscosity of the slag, it is difficult to remove the slag and the unclean removal of the slag, the slag inclusion defects of the casting are significantly increased, and the phenomenon of spheroidization recession occurs many times.

The analysis shows that MGS and cezs3 in the slag react with oxygen in the air

2MgS+02=2Mgo+2S

2Ce2S3+3O2=2Ce2O3+6S

Cause the so-called "sulfur recovery" phenomenon and promote the decline of spheroidization. In this way, the spheroidizing agent in front of the furnace is increased from 1.3% to 1.5%. As a result, there was no spheroidization decline under the same conditions. During production, it was found that during the period when the use of cryolite powder was stopped, the defects of subcutaneous pores in the processed products increased by 10-15% compared with the previous ones.

As for the addition amount of cryolite powder, researchers have also done experiments: when 0.025% - 0.03% cryolite powder is added into the treated ladle, the sample is spheroidized to grade 1-2; Add 0.06% cryolite powder, and the sample is spheroidized to grade 3-3.5; Add 0.1% ice crystal powder, and the sample is spheroidized to grade 5.

The researchers believe that excessive addition of cryolite powder is not only unfavorable to spheroidization, but also the more a13f3 released by the interaction between cryolite powder and high-temperature molten iron

Na3AIF6→3NaF+AlF3

AlF3 is a toxic gas. In the production of nodular iron, the nodularization process stipulates that the addition amount of ice crystal plant powder is 0.02-0.035% of the weight of molten iron.