The product can be widely used in heavy metals such as lead, arsenic, chromium, cadmium and mercury in waste water. Coagulation precipitation method can remove insoluble COD in wastewater, and form iron phosphate precipitation with orthophosphate in wastewater, so as to achieve the effect of phosphorus removal. And the combination is usually remedied by Fecl3 after the addition of excess sodium sulfide. The main reason is that sodium sulfide in the treatment of heavy metal dosage is too large, excessive sodium sulfide will remain in the water, so that the water becomes black and smelly, so the usual treatment method is to add iron salt, the formation of iron sulfide precipitation.

Sodium sulfide manufacturer

Reaction equation of Fecl3 with sodium sulfide.

When the content of Na2S is low, the solution is milky yellow (S) and smelly (H2S)2Fe3++3S2-+4H+=2.

Excessive Fe2++S↓+2H2SNa2S will produce black precipitation, and 2Fe3++3S2-=Fe2S3 will be generated after ↓ shaking, the precipitation will not disappear, no obvious rotten egg odor is due to too much sodium sulfide, the solution is alkaline, Fe2S3 is stable in alkaline conditions, black sediment Fe2S3 is insoluble. In addition, because the solubility of Fe2S3 is less than that of FeS, ferric iron cannot be reduced.