The Comprehensive Utilization Research Of Alpha-nitroso-beta-naphthol Cobalt Slag

At present, there are four main methods about separating cobalt from zinc liquid in thezinc hydrometallurgy factory in our country, among them, using beta-naphthol as precipitantcobalt removal is one of the important processes. But alpha-nitroso-beta-naphthol cobalt slagof this process has not become a good comprehensive utilization. A large number of studieshave shown that at present the valuable metals of alpha-nitroso-beta-naphthol cobalt slag inour country are recycled by the method of calcination, however the reuse of the precipitantpart was not reported.The raw material in this reseach is alpha-nitroso-beta-naphthol cobalt slag obtained fromshangxi zinc hydrometallurgy. Four section processes are used to deal with it: pickling inremoving impurity, acidic denitrification process, alkaline reduction of recycling cobalt,purification of cobalt products, and purification of beta-naphthol. This method can bothcollect metal cobalt from that slag, and convert precipitant to recycling of beta-naphtholeffectively.First pickling process conditions for removing impurity are as following: the liquid-solidratio is3:1, sulfuric acid concentration is1.0mol/L, room temperature, acid pickling time is30min. Under the condition of the process, the elution rate of iron can reach50%, the elutionrate of zinc basicly can reach more than90%, other basic metal impurity can be removedcompletely.Using the solvent diffusion way, alpha-nitroso–beta-naphthol cobalt slag is dissolved inmixed xylene with formic acid as reducing agent, nitrogen reduction is reacted under thecondition of the distillation unit. After denitrification reaction equilibrium, it need to betransformed into the reflux device, and sodium hydroxide solution is added into it. Reductedcobalt can be precipitated and beta-naphthol could be translated into that sodium salt.Afterfiltering, residue is leached cobalt by hydrochloric acid. Filtrate is distilled to remove organicsolvent and after distillation filtration, beta-naphthol crude product can be getten byhydrochloric acid neutralization.Through the single factor and orthogonal experiment, the process conditions for themention of cobalt are following:1.50g cobalt slag by pickling, mixed xylene250mL assolvent, the amount of methane acid is five times of its theory, reflow temperature. Under theprocess conditions,the leaching one-stage rate of cobalt is74.68%, one-stage percent yield of beta-naphthol is52.73%.The cobalt chloride solution was purificated by H2O2oxidation and P204, and thenturned it into cobalt oxalate precipitation, then through calcining to cobalt oxide, whichcontained73.1%of metal cobalt.In addition, beta-naphthol getten from precipitating agent was purificated byrecrystallization purification. Its purity closes to commercially available analysis pure betanaphthol by thin layer chromatographic analysis and melting point determination. Its infraredspectroscopy and GC-MS test results are consistent with the standard spectra of beta naphthol.