How to identify the quality of silicon slag?

How to identify the quality of silicon slag when purchasing silicon slag:
Silicon slag is mainly a ferroalloy product that has been carbonized. Its internal elements are mostly silicon slag (Sic). Generally, products with higher silicon slag content will be greener in color, while products with lower silicon slag content will be grayer. , and silicon slag with a silicon slag content of 50% to 70% turns black, so when we select silicon slag, we can look at the color of the silicon slag product and quickly select silicon slag based on the color of the silicon slag.