History of Pure Salt

Salt supply alternatives have been studied and discussed in presentations prior to this one and within the companies involved with making this critical selection for delivering salt to a corn field or expanding existing membrane plant, and in some cases including supply to a mercury cell plant. In this talk, I will briefly review the alternatives, and then focus on close coupling the chlor-alkali plant with an evaporated salt plant, the last alternative listed, and then producing Ultra Pure Salt within that base facility.

A common practice for supplying a membrane plant, particularly in the USA, is to “Tee” it in to an existing diaphragm plant and use the CP [Caustic Process] salt from the diaphragm plant to re-saturate depleted brine from the membrane plant before processing it through the diaphragm plant. With this scheme, short of very large intermediate storage facilities, the operating utility of the two plants will be lower than that of either stand alone plant, and production rate flexibility in the system is limited by the salt balance across the site and thus fixes the size membrane plant that can be linked the diaphragm unit. The limitation is about 45% membrane and 55% diaphragm capacity, which varies somewhat with the specific design.