Process control brine filters

In most commercial processes, borax is obtained from lake brines, tincal and colemanite. The primary salt constituents of brine are sodium chloride, sodium sulfate, sodium carbonate and potassium chloride. The percent composition of borax as Na2B40 in brine is generally in the range 1.5 to 1.6%. Borax is separated from these salts by various physical and chemical processes. The brine solution (mixed with mother liquor) is subject to evaporation and crystahzation for the continuous removal of NaCl, Na2C03 and Na2S04, respectively. The hot liquor consists of concentrated solution of potassium salts and borate components of the brine. The insoluble solid particles are filtered out and the liquor is cooled rapidly in continuous vacuum crystallizers under controlled conditions of temperatures and concentrations to crystallize KCl. Cystallization of borax along with KCl from the concentrated liquor must not occur at this stage. KCl is separated from the hquor by filtration. Bicarbonate then is added to the liquor to prevent any formation of sodium... 

Dead Seas Periclase Ltd., on the Dead Sea in Israel, uses yet another process to produce magnesium oxide. A concentrated magnesium chloride brine processed from the Dead Sea is sprayed into a reactor at about 1700°C (127,128). The brine is thermally decomposed into magnesium oxide and hydrochloric acid. To further process the magnesia, the product is slaked to form magnesium hydroxide which is then washed, filtered, and calcined under controlled conditions to produce a variety of MgO reactivity grades. A summary of MgO purities, for the various processes is given in Table 20. 

Process documentation 2, drying chamber with shelves 3, operation control 4, ice condenser 5, vacuum pump with exhaust filter 6, refrigeration machine for the ice condenser 7, refrigeration machine for the shelves 8, circulation pump for the brine 9, heat exchanger (Lyovac GT 6, AMSCO Finn-Aqua, D-50354 Hiirth, Germany). 

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