Method used for simultaneous extraction of ammonium sulfate and ammonium thiocyanate from coking waste liquid

Abstract

The invention discloses a method used for simultaneous extraction of ammonium sulfate and ammonium thiocyanate from coking waste liquid. The method comprises following steps: coking waste liquid is filtered so as to remove impurities, and is delivered into a stirrer; air is pumped into the stirrer, a catalyst is added, and reaction is carried out for 3 to 10h at 50 to 90 DEG C with a pH value ranging from 5 to 6; active carbon is adopted for heating decoloring of filtered coking waste liquid at 55 to 85 DEG C for 0.3 to 1.5h; H2O2 is added for 1 to 3h of oxidation, an obtained product is subjected to evaporative crystallization and filtration, and an obtained crystal is collected; the crystal is delivered into a reactor, an alcohol organic solvent is added, an obtained mixture is mixed fully, and is filtered so as to obtain ammonium sulfate crystal; an obtained ammonium thiocyanate alcoholic solution is subjected to evaporative crystallization so as to obtain ammonium thiocyanate crystal, and an evaporated alcoholic solution is collected and recycled. The method can be used for simultaneous preparation of ammonium sulfate and ammonium thiocyanate; purifying process can be recycled; industrial energy consumption is low; recovery rate of ammonium sulfate and ammonium thiocyanate is high; no waste is discharged; the method is green, and is high in recovery rate, low in cost, and high in purity; and no pollution is caused.

Description

technical field [0001] The invention belongs to the technical field of coking waste liquid treatment, in particular to a method for simultaneously extracting ammonium sulfate and ammonium thiocyanate from coking waste liquid. Background technique [0002] Coking waste liquid is the waste water produced in the process of coal coke, gas purification and coking product recovery. The waste water discharge volume is large and the water quality is complex. It mainly contains color catalysts, various metal ions, suspended sulfur, various inorganic salts, phenol, oil Hydrogen, naphthalene, pyridine, quinoline, anthracene and other heterocyclic and polycyclic aromatic compounds such as tar and other organic substances are toxic, harmful and difficult to degrade high-concentration organic wastewater. [0003] At present, domestic coking enterprises generally adopt HPF desulfurization process, and the desulfurization waste liquid produced by this process mainly contains three kinds of ...

AI Technical Summary

Problems solved by technology

[0003] At present, domestic coking enterprises generally adopt HPF desulfurization process, and the desulfurization waste liquid produced by this process mainly contains three kinds of salts: (NH 4 ) 2 SO 4 ,(NH 4 ) 2 S 2 o 3 ,(NH 4 ) SCN, these three kinds of auxiliary salts are continuously accumulated in the desulfurization system, which reduces the desulfurization efficiency.

[0004] At present, the treatment methods of coking waste liquid mainly adopt biological treatment method, activated sludge method, biological iron method and other treatment methods, and the corresponding treatment methods deal with different harmful substances, but these methods have poor treatment effects on ammonia nitrogen. Coking enterprises will exclude part of the waste liquid from being sprayed directly on the coal pile or on the mixed coal in the coal tower to return to coke oven production. The three kinds of salts will continue to accumulate in the system, causing serious corrosion of equipment, degradation of coke quality, and environmental pollution.