The harm of phosphogypsum with those

                                         The harm of phosphogypsum with those

When producing wet-process phosphoric acid, phosphate rock by sulfuric acid decomposition of phosphate rock containing Fe, Al, Mg impurities compound most decomposition, soluble in phosphoric acid solution. A few not decomposition of phosphate rock, fluorine compounds, acid insolubles, a tiny particles of organic matter in the carbide and the reaction of calcium sulfate precipitate out together. Phosphoric acid solution with calcium sulfate precipitation filtration separation, filter cake washing operation after a certain, but limited to reaches a certain concentration of phosphoric acid to allow the balance of water consumption. The extent of the filter cake is unlikely to be completely wash, or calcium sulphate filter cake will contain a small amount of acid of not be washed. This contains a small amount of wet process phosphoric acid production not decomposing phosphate rock and free acid dihydrate calcium sulphate is known as the phosphorus gypsum.

As the raw materials used in manufacturing wet-process phosphoric acid phosphate rock quality different, dephosphorization of phosphorus gypsum plaster production line of the composition is not the same. High grade Morocco phosphate rock as raw material, adopt different system of phosphoric acid by wet process phosphoric acid chemical composition of phosphorus gypsum. With containing phosphorus pentoxide 31-3% ~ 33. 0% of American Florida selected phosphate rock in producing wet-process phosphoric acid (water) to produce the typical composition of phosphorus gypsum as shown in table 2-5 azbuk.

Because most phosphate rock contains a small amount of radioactive elements, comprehensive utilization of phosphogypsum acid phosphate acid solution with higher percentage of uranium compounds dissolved in acid; But the natural decay of the uranium content of radium in sulfuric acid with calcium sulfate precipitation and morphology of radium. Like radon and other radioactive radium.

China environmental science research institute of 17 p enterprises nationwide by solid component analysis has been done for the phosphogypsum. Analysis results show that the main impurity phosphorus gypsum is fluoride and phosphorus pentoxide, and show a strong acid. A lower the pH of the phosphorus gypsum is 1. 9. Fluoride content in the ideal of 2. 04%; Total phosphorus pentoxide ideal of 17. 1%; Soluble phosphorus pentoxide ideal up to 5. 7%. The phosphorus gypsum storage field produced by the leaching water obviously very big to the harm of environment. ,