| A novel kind of Schiff base phase transfer catalysts was synthesized, then the catalysts were applied in synthesis of N-alkoxycarbonyl isothiocyanate and its derivatives, and their floatation property was studied by floating Peru copper ores.Three kinds of Schiff base catalysts were designed and synthesized, then their synthesis conditions were optimized. In the presence of Schiff base JB-1, QA-3, JA-3, N,N-dimethylaniline, pyridine and quinoline as phase transfer catalysts, N-alkoxycarbonyl isothiocyanate was produced by reacting ethyl chloroformate with sodium thiocyanate in cyclohexane and L-oil, respectively. By comparison of the catalytic performance, JA-3 displayed efficient catalytic performance in both solvent. Therefore, JA-3 was selected as the catalyst for producing N-alkoxycarbonyl isothiocyanate, and the synthesis conditions were optimized in the cyclohexane solvent and L oil solvent. Based on the researches, it had been showed that conversion rate of N-alkoxycarbonyl isothiocyanate were above 96% when the catalyst JA-3 was employed.Under the optimum conditions, catalyst JA-3 was used for synthesis of N-alkoxycarbonyl isothiocyanate intermediate product, by which a new novel collector MT-20 was synthesized. Then the floatation nature of collector MT-20 was tested through floating the copper ore sample form Peru. The results showed that both MT-20 and Mac-12 had comparable collecting power which was stronger than it of Z-200 for copper minerals, and the recovery was 92.64% and 92.59% respectively, while the selectivity of MT-20 was higher than if of Mac-12, for that the acquired rough concentrate grade was 7.07% and 5.85% respectively. Moreover, the recovery for arsenic by using MT-20 as collector was 7.74% lower than it by using Mac-12, so it was good for improving the grade and recovery of copper concentrate by employing MT-20 as collector for Peru copper ores. It was proved that MT-20 had excellently collecting power and high selectivity for copper minerals. |
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