Phosphorus removal method for high-impurity and phosphorus-containing ammonium heptamolybdate

The invention discloses a phosphorus removal method for high-impurity and phosphorus-containing ammonium heptamolybdate. The phosphorus removal method is characterized in that: aiming at a condition that an impurity element phosphorus in a produced ammonium heptamolybdate product exceeds the standards according to special requirements of extracting certain rare and precious metal in a molybdenitesmelting and processing process, the invention researches and develops a novel technology for removing phosphorus by adopting combined precipitation of magnesium salt and magnesium oxide; the technical method is used for treating the high-impurity and phosphorus-containing ammonium heptamolybdate; a qualified ammonium heptamolybdate product with the phosphorus content of 5ppm or lower can be stably produced; the phosphorus removal rate reaches 94 percent or more and the primary crystallization yield reaches 90 percent. By adopting the method disclosed by the invention, the problem that a phosphorus-containing impurity