SOP, sulfate of potash (K2SO4) is one of the most common potash fertilizers used by farmers to grow crops. There are operations that produce potash fertilizer by using salt mixtures from natural brines. This requires brine with high sulfate levels that are typically found in salt lakes. The steps in the processing of potash are usually separation, drying and compaction/granulation. In order to prevent and reduce corrosion, equipment is made of stainless steel.