Background and overview[1]
Calcium orthophosphate Cd3(PO4)2=527.14, white amorphous powder, melting point 1500℃. Insoluble in water, soluble in acid and ammonium salt solution. It is derived from the reaction of sodium phosphate solution and cadmium sulfate solution.
Apply[2-3]
Examples of applications of calcium orthophosphate are as follows:
1) Prepare phosphate and a mixed product of sodium phosphate and potassium sulfate. After suction filtration of the manganese-containing waste liquid obtained from the production of hydroquinone, the clarified filtrate containing manganese sulfate, ammonium sulfate, and sulfuric acid and the filtrate containing elemental residues are obtained. Cake, the filter cake containing elemental residue reacts with excess sulfuric acid to obtain a solution containing calcium sulfate, magnesium sulfate, zinc sulfate, sodium sulfate, aluminum sulfate, cadmium sulfate and nickel sulfate, and then mixed with the potassium phosphate solution to obtain a solution containing phosphoric acid The mixed solution of phosphate and potassium sulfate of calcium, magnesium phosphate, zinc phosphate, sodium phosphate, aluminum phosphate, calcium orthophosphate and nickel phosphate is filtered to obtain calcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate and orthophosphate. The phosphate filter cake of calcium and nickel phosphate products and the filtrate containing mixed sodium phosphate and potassium sulfate; the phosphate filter cake is washed, dried, separated and crushed at the latest price of PVC resin powder to obtain phosphate products; the phosphate product containing sodium phosphate and potassium sulfate is obtained. The filtrate of potassium sulfate is distilled under reduced pressure, cooled and crystallized to obtain a mixed product of sodium phosphate and potassium sulfate.
2) Prepare a secondary battery negative electrode, including a metal foil and a dense metal phosphate film disposed on the surface of the metal foil. The metal foil serves as a negative electrode current collector and anode active material at the same time. The material of the metal foil includes aluminum and copper. , any one of iron, tin, zinc, nickel, manganese, lead, antimony, cadmium and bismuth, or an alloy containing at least one of the above metal elements; the material of the metal phosphate film includes aluminum phosphate, copper phosphate, iron phosphate , one or more of tin phosphate, zinc phosphate, nickel phosphate, manganese phosphate, lead phosphate, antimony phosphate, calcium orthophosphate and bismuth phosphate. The surface of the metal foil of the present invention is provided with a metal phosphate film that is electronically insulating and capable of migration of lithium ions. The metal phosphate membrane plays a functional role similar to that of a solid electrolyte membrane; it improves the compatibility between the negative electrode and the electrolyte, and improves the battery’s charge and discharge efficiency, battery cycle performance, high and low temperature performance, and safety performance. The invention also provides a method for preparing a negative electrode of a secondary battery and a secondary battery.
