Silicon carbide raw material

The conversion of silicon carbide raw material 45 ferrosilicon to 75 ferrosilicon requires a short process and no waste products. The technical operation of the conversion process shall be flexibly mastered according to the size of the furnace, the amount of material accumulated in the furnace and the actual conversion experience. Generally speaking, the conversion procedures are roughly as follows:

1. 2 ~ 3 shifts before conversion, lower the electrode as far as possible to keep the electrode long enough and deeply embedded in the furnace charge, so as to heat the furnace bottom and improve the furnace temperature.

2. Reduce the material level eight hours before conversion, minimize the 45 ferrosilicon accumulated in the furnace, and control the silicon content of the alloy close to the upper limit.

3. After the material level is lowered, stop adding 45 ferrosilicon, start adding 4 ~ 5 batches of furnace charge without strip steel scrap (the batch of silica is 200kg), then output the last furnace of 45 ferrosilicon and discharge the iron as much as possible. According to the analysis of iron quantity in front of the furnace, add an appropriate amount of steel chips to the ladle and adjust the qualified products.

4. Continue to add the furnace charge without strip steel chips. Generally, the first furnace of ferrosilicon can be produced after 5 ~ 6 hours. After it is qualified, start adding 75 ferrosilicon. It should be noted that the feed level should not be raised too quickly during transfer feeding. The newly built molten iron ladle shall be used for the first furnace of ferrosilicon.

According to the compactness and shape of products, there are sintering method, melting casting method and melting injection method. Sintering method is to pre burn some raw materials into mature materials, crush and screen them, then mix them with raw materials according to a certain proportion, and then form, dry and burn them. The purpose of raw material pre burning is to burn away the moisture, organic impurities and sulfate decomposition gas, so as to reduce the firing shrinkage of the product and ensure the accuracy of the overall dimension of the product. The raw materials need to be screened after crushing and grinding, because the billets are graded by powder with different particle sizes, which can ensure the closest stacking and obtain dense billets.