Removal of fluorine from commercial phosphoric acid produced by the wet method was investigated. Defluorination is based on precipitation of fluorine as sodium fluorosilicate using local available materials. This was achieved by the addition of white sand to the crude acid (produced locally) followed by the addition of sodium chloride or sodium carbonate to precipitate sodium fluorosilicate. The effects of temperature, agitation time and the quantities of added materials on the percent of fluorine removed were studied. based on the experimental results, the fluorine content in the crude acid was successfully reduced from 0.88% to 0.11%. reduction in the concentration of fluorine was accompanied by the reduction in the concentration of certain trace hazardous impurities. using the best conditions for treatment of the crude acid produced, a phosphoric acid product which can be used safely as animal feed ingredient was obtained |
