Study on condition of defluorination in wet-process phosphoric acid production with precipitation method

Based on the precipitation reaction principle of defluorination in wet-process phosphoric acid production,sodium carbonate and diatomite have been experimented to defluorine from phosphoric acid with different conditions.The factors such as quantity,reaction time,temperature of the reaction were tested.The results show that the fluorine content in the sample of fifty grams which contains 0.74% fluorine can be decreased to less than 0.18%,when using 0.8 g sodium carbonate and 0.2 g diatomite to react for 50 min at 30～40 ℃.This can meet the quality need of producting calcium hydrogen phosphate of animal feed grade.(F-≤0.18%,HG2636— 94).