Harmless Treatment of Phenylhydrazine Hydrochloride Production Effluent: From Lab Scale to Pilot Scale

Abstract

More economical and effective technology is being developedin the wastewater treatment process to deal with the products of phenylhydrazine hydrochloride (PHH). Fixed ammonium in the effluent is converted to free ammonia by utilizing the neutralization reaction, and the sulfate is removed in the form of gypsum. Meanwhile, the toxic PHH is recycled according to the extraction and re-extraction technology. The raffinate phase is reused through boiling off ammonia vapor. The recovery rates of PHH reach 93.3% in the laboratory and 92.9% at the pilot scale, respectively. Compared with our previous work, the cost of the new technology is ~1/10 of the original, and the profit increases ~3.5-fold. Consequently, it has great potential to be applied to industrial production.