Comprehensive Purifying Wastewater from Ammonium Paratungstate Production Process

In China, ammonium paratungstate (APT) is mainly produced by method of ion exchange. The wastewater generated from the process of tungsten smelting is composed of two parts: ion exchange and dilute ammonia which can not be recovered. The ammonium and nitrogen contented in dilute ammonia nitrogen is about 3000~4000mg/L; arsenic in solution after exchange is about 2~3.5mg/L, and phosphorus is 10~20mg/L, fluorine is 100~200mg/L, and it’s seriously exceeded the national standard.

At present, NaOH-adding-stripping method is mainly used in dilute ammonia for removing ammonia and nitrogen, but the alkali consumption volume is high, ammonia nitrogen removal is not complete, and low concentration ammonia directly emissions cause secondary pollution; and ion exchange liquid mainly use ferrous sulfate silica fume addition polymerization aluminum iron precipitation of arsenic removal, the method is poor effect   for high arsenic content in tungsten liquid and cannot simultaneously remove phosphorus and fluorine.

Test materials: dilute ammonia recovered in ammonium paratungstate crystallization and ammonia liquid after remove ammonia and nitrogen, the tungsten ion exchange liquid, industrial (the content of calcium is 30%) and hydrochloric acid.
Specific steps:
1. Tungsten smelting wastewater ammonia and nitrogen removal, under the condition of normal temperature, the mass ratio of bleaching powder and ammonia nitrogen is 6.9~34.7, pH = 4~12, time for 10min, stirring speed at 600r/min;
2. Deeply remove arsenic, phosphorus and fluorine, under the condition of normal temperature, volume ratio of liquid after removed ammonia.

• < Prev
• Next >