硫氨酯捕收剂的制备及浮选性能

Preparation and flotation performance of thionocarbamates

  • 摘要: 为解决硫氨酯捕收剂制备过程中副产品处理困难、存在污染等问题,设计了四种新工艺制备乙硫氨酯(IPETC),分别联产对叔丁基苄基硫醇(BBSH)、苄基三硫代碳酸盐(BTTC)、苄硫基乙基黄药(SBEX)、二苄基二硫醚。在优化的合成工艺条件下,合成IPETC联产BBSH,得到含IPETC和BBSH的复合捕收剂,其中IPETC的质量分数为51%,BBSH的质量分数为41%,IPETC和BBSH的收率达到95%;合成IPETC联产BTTC,IPETC和BTTC的收率分别达到94%和95%,纯度分别为91%和82%;合成IPETC联产SBEX,IPETC的收率和纯度分别达到89%和95%,SBEX的收率和纯度分别为93%和91%;合成IPETC联产二苄基二硫醚,IPETC的收率和纯度分别达到93%和92%,二苄基二硫醚的收率和纯度分别达到95%和94%。考察了制备的复合捕收剂(IPETC与BBSH)对铜钼矿的浮选性能,结果表明,复合捕收剂对铜钼矿表现出良好的捕收性能。联产的新型捕收剂SBEX、BTTC对黄铜矿的捕收力略强于异丁基黄药,对黄铁矿具有较好的选择性,可替代异丁基黄药浮选硫化铜矿。红外光谱和X射线光电子能谱分析结果表明,SBEX、BTTC与黄铜矿作用时,捕收剂分子中的C=S和C—S与矿物表面的金属Cu作用,生成捕收剂与铜的表面络合物吸附在黄铜矿的表面。

     

    Abstract: To address the problems of byproduct treatment and pollution in thionocarbamate preparation, four novel processes for preparing O-isopropyl-N-ethyl thionocarbamate (IPETC) were designed, which can coproduce 4-(tert-butyl)benzyl mercaptan (BBSH), sodium benzyl trithiocarbonate (BTTC), sodium O-benzylthioethyl xanthate (SBEX), and benzyl disulfide, respectively. All the products were confirmed via FTIR and mass spectrometry. The composite collector (IPETC and BBSH mass contents were 51% and 41%, respectively) was synthesized via one-pot reaction of sodium isopropyl xanthate, 4-tert-butylbenzylchloride, and ethylamine using tert-butyl alcohol as solvent. The yield of IPETC and BBSH was 95% in the process of coproducing IPETC and BBSH. Specifically, BTTC and IPETC were synthesized via a reaction of sodium isopropyl xanthate, benzyl chloride, ethylamine, carbon disulfide, and sodium hydroxide. The IPETC and BTTC yields were 94% and 95% with a purity of 91% and 82% in the process of coproducing IPETC and BTTC, respectively. Meanwhile, SBEX and IPETC were synthesized via reaction of sodium isopropyl xanthate, 2-chloroethanol, ethylamine, benzyl chloride, carbon disulfide, and sodium hydroxide. The IPETC and SBEX yields were 89% and 93% with a purity of 95% and 91% in the process of coproducing IPETC and SBEX, respectively. Benzyl disulfide and IPETC were synthesized via a reaction of sodium isopropyl xanthate, benzyl chloride, ethylamine, and hydrogen peroxide. The IPETC and benzyl disulfide yields were 93% and 95% with a purity of 92% and 94% in the processof coproducing IPETC and benzyl disulfide, respectively. The flotation response of copper-molybdenum ore independent with IPETC and BBSH collectors and with their mixture was assessed. The flotation results indicate that the composite collector displays a superior collecting capability for copper sulfide ore. Further, the combination of IPETC and BBSH could give rise to a synergistic effect, significantly enhancing the overall flotation performance. The flotation performance of SBEX and BTTC on chalcopyrite and pyrite was also investigated. The flotation results indicate that SBEX and BTTC exhibited better collecting performance than sodium isobutyl xanthate (SIBX), which can replace SIBX for the flotation separation of copper sulfide. FTIR spectra and X-ray photoelectron spectroscopy analyses were conducted. The results indicate that when all three sulfur atoms in BTTC bond to the mineral surface, the hydrophobicity increases when compared to xanthates, wherein oxygen does not bond to the surface. Further, the thioether structure can increase the hydrophobicity of SBEX on the chalcopyrite surface, and SBEX features a higher collecting recovery toward chalcopyrite than SIBX. The results indicate that BTTC and SBEX might bond with copper atoms on the chalcopyrite surface through their sulfur atoms to form BTTC-Cu and SBEX-Cu surface complexes.

     

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