丁基二硫代碳酸钾臭氧氧化过程中C与S迁移特征的研究

发布时间：2018-07-10 02:10

本文选题：丁基二硫代碳酸钾 + 臭氧氧化　；参考：《广东工业大学》2015年硕士论文

【摘要】：对于铜铅锌硫化矿,国内外最常用的选矿方法为浮选法。在浮选过程中,需添加巯基类有机化合物作为硫化矿物的捕集剂。其中丁基二硫代碳酸钾(Potassium n-Butyl Xanthate, PBX)是最常用的巯基类浮选捕集剂。除了被硫化矿物表面吸附外,其余的PBX会残留在浮选废水中,对环境造成较大的影响。2012年实施的《铅、锌工业污染物排放标准(GB25466-2010)》对铅锌浮选废水的污染控制提出了更高的要求。本论文采用臭氧氧化法对PBX模拟废水及其实际选矿废水进行处理,探究不同臭氧氧化条件对PBX去除率的影响,研究了PBX模拟废水在臭氧氧化过程中碳、硫元素的迁移特征,对其臭氧氧化产物进行分析,并进行了实际选矿废水臭氧氧化试验。首先,使用不同浓度臭氧对100mg/L PBX模拟废水进行氧化分解试验。结果表明,在不同臭氧浓度的条件下,PBX的去除率均能够达到100%,而且臭氧输出浓度越高,PBX去除速率越快。但COD和TOC去除率仅达到50.9%和28.5%,这表明PBX在臭氧氧化过程中未能完全矿化,生成了小分子有机物稳定存在于水体中。同时,臭氧氧化过程中模拟废水pH从初始值7.50下降至3.18。其次,使用TOC分析仪和离子色谱研究了PBX臭氧氧化过程中碳、硫元素的迁移特征。结果表明,碳、硫元素在气相和液相体系中的分布比例不受臭氧浓度的影响,当PBX被彻底分解时,71.5%碳元素和79.4%硫元素存在于液相体系中,28.5%碳元素和20.6%硫元素存在于气相体系中,液相体系中的碳和硫分别以TOC和SO42-的形式存在。臭氧氧化反应的开始阶段,可能是臭氧在水体中发生间接反应从而产生·HO2和·O2-和H+,其中·HO2和·O2-优先与PBX中的巯基发生反应生成SO42-,剩下的H+导致pH下降。再者,使用GC/MS和UPLC/MS相结合的分析方法对臭氧氧化产物进行测定。结果表明,PBX (C4H9OCSSK)被臭氧氧化分解后产物是SO42-和C4H9OH,SO42-由PBX极性基中的硫氧化而成,C4H9OH由PBX中的C4H9-O-C键断键而成。当羟基自由基抑制剂(C4H9OH)出现后,臭氧在水体中间接反应受到抑制,致使反应后期pH趋向稳定。最后,采用臭氧氧化法与自然降解法对实际浮选废水进行净化试验。结果表明,臭氧氧化比自然降解更能有效去除实际废水的COD,而且节省时间。臭氧氧化法对尾矿库外排水的处理效果尤为明显,通过适当调试可作为选矿厂尾矿库外排废水的深度处理手段。同时在试验过程中,发现各单元作业废水(除洗矿废水)与尾矿库外排水臭氧氧化处理后SO42-浓度的持续上升,推测该类水体中存在大量低价态含硫化合物(价态小于+6)。
[Abstract]:Flotation is the most commonly used flotation method for copper-lead-zinc sulphide ore at home and abroad. In the flotation process, sulfhydryl organic compounds should be added as trapping agents for sulphide minerals. Potassium n-Butyl Xanthate (PBX) is the most commonly used sulfhydryl flotation trapping agent. In addition to being adsorbed on the surface of sulphide minerals, the remaining PBX will remain in flotation wastewater, which will have a great impact on the environment. The discharge Standard of lead and Zinc Industrial pollutants (GB25466-2010), which was implemented in 2012, puts forward higher requirements for pollution control of lead-zinc flotation wastewater. In this paper, PBX simulated wastewater and its actual mineral processing wastewater were treated by ozone oxidation method. The effects of different ozonation conditions on PBX removal rate were investigated, and the characteristics of carbon and sulfur migration in PBX simulated wastewater during ozone oxidation were studied. The ozonation products were analyzed and the ozonation test of mineral processing wastewater was carried out. First, 100 mg / L PBX simulated wastewater was oxidized and decomposed with different concentrations of ozone. The results show that the removal rate of PBX can reach 100% under different ozone concentration, and the higher the ozone concentration is, the faster the removal rate of PBX is. However, the removal rates of COD and TOC were only 50.9% and 28.55.This indicated that PBX could not be completely mineralized during ozonation, resulting in the formation of small molecular organic compounds stable in water. At the same time, the pH of simulated wastewater decreased from 7.50 to 3.18 during ozone oxidation. Secondly, the migration characteristics of carbon and sulfur during PBX ozone oxidation were studied by TOC analyzer and ion chromatography. The results show that the distribution of carbon and sulfur in the gas phase and liquid phase is not affected by the ozone concentration. When PBX is completely decomposed, 71.5% carbon and 79.4% sulfur are present in the liquid phase system, 28.5% carbon and 20.6% sulfur are present in the gas phase system. Carbon and sulfur in liquid phase system exist in the form of TOC and so 4-2 -, respectively. In the initial stage of ozonation reaction, it may be that ozone reacts indirectly in water to produce H _ 2, O _ 2- and H, where O _ 2 and O _ 2-preferentially react with sulfhydryl group in PBX to form so _ 42-and the remaining H results in a decrease of pH. Furthermore, the ozonation products were determined by GC / MS and UPLC / MS. The results show that the products of PBX (C _ 4H _ 9OCSSK) decomposed by ozone are so _ 42- and C _ 4H _ 9OH _ 2- oxidized from sulfur in the polar group of PBX to form C _ 4H _ 9OH and C _ 4H _ 9-O-C bond in PBX. When the hydroxyl radical inhibitor (C _ 4H _ 9OH) appeared, the indirect reaction of ozone in water was inhibited, which resulted in the stabilization of pH in the later stage of reaction. Finally, ozone oxidation and natural degradation were used to purify flotation wastewater. The results show that ozonation is more effective than natural degradation in removing COD from waste water and saving time. The ozone oxidation process is especially effective in treating the waste water from the tailings reservoir. It can be used as an advanced treatment method for the waste water discharged from the tailings reservoir of the concentrator through proper adjustment. At the same time, it was found that the concentration of so _ 4 _ 2-- increased continuously after the ozonation treatment of each unit wastewater (except washing wastewater) and the tailings reservoir, and it was inferred that there were a large number of low-priced sulfur compounds (valence < 6) in this kind of water.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X753

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