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Show 93 brine is pumped or allowed to flow out of the pond. In moderate practice, the pumping or flowing in and out of the pond and the evaporation all take place simultaneously and continuously. COMPOUNDS EXTRACTED FROM THE GREAT SALT LAKE Sodium Chloride Sodium Chloride ( NaCl), or common table salt, is the easiest mineral to produce from the Lake brine and is the first mineral to precipitate during solar evaporation. When the desired thickness of precipitated salt is built up on the bottom of the pond, it is drained sufficiently for common construction vehicles and machines to go into the pond to harvest the salt. The salt, which is also called halite, is further processed by crushing, washing with enough water to carry away the contaminants without dissolving substantial quantities of salt, drying, and screening into the desired particle sizes. If necessary, salt for the food industry may be redissolved in pure water, filtered and reevaporated to produce a cleaner salt. The brine should be clear or free of suspended matter, which not only affects the appearance of the salt produced but also causes finer salt to precipitate, a significant effect because coarse salt is generally more valuable than fine sale. Solar evaporation produces a relatively high grade salt. Utah salt is generally 99.6+ percent pure. Other standard grades of salt are: Northern Rock Salt ( 96 percent NaCl, 3 percent insoluble); Southern Rock Salt ( 99- percent NaCl, 1 percent insoluble); vacuum pan ( 99.7 percent NaCl); and Mixed Grades ( salt with additives). Figure 17 shows salt production in Utah, most of which is from |
