磷渣基地聚物材料的制备及其固化含砷废渣的研究

发布时间：2018-01-25 09:39

本文关键词： 含砷废渣粉煤灰磷渣固化/稳定化浸出毒性　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文以云南某冶炼厂产生的含砷废渣为研究对象,研究含砷废渣在不同环境下砷毒性浸出特性;通过单因素筛选实验、多因素正交实验,考察了磷渣、粉煤灰等物料的掺量以及化学外加剂的种类和掺量对地聚物材料性能的影响,制备了力学性能优良的地聚物材料;利用磷渣-粉煤灰基地聚物材料固化含砷废渣,考察了含砷废渣固化体在不同养护条件下的力学性能、砷浸出特性;通过冻融实验、硫酸盐侵蚀实验初步探索地聚物材料固化体的耐久性。研究表明:(1)含砷废渣在不同pH环境下,砷的浸出浓度差异比较大,中性环境下砷的浸出浓度比较稳定,但仍大于1000mg·L-1;外掺石灰可以有效的控制含砷废渣的浸出浓度,但石灰处理后含砷废渣耐久性极差,在自然环境下堆存,极易造成二次污染;外掺水玻璃掺量不易过高,掺量太高时,含砷废渣的浸出浓度升高。(2)通过单因素实验、多因素的正交实验确定了地聚物材料中磷渣、粉煤灰、高钙灰的最佳掺量为磷渣75%、粉煤灰15%、高钙灰10%,水玻璃的模数为M=1.2、掺量为4%(外掺)时,材料力学性能最好,常压蒸汽养护24h,抗压强度为40.98MPa;通过XRD、FTIR、SEM的手段对地聚物材料进行表征,其物相组成主要为无定形相,具有丰富的网状结构。(3)通过对含砷废渣进行分析,其主要组成为As2O3和CaF2,砷含量为14.2%,考察了不同pH环境下其砷毒性浸出特性,其最低砷浸出浓度为1350mg·L-1,属于危险废弃物。利用磷渣基地聚物材料对其进行固化处理,考察了养护时间及养护方式、砷渣掺量等因素对固化体性能的影响,最佳养护方式为蒸汽养护,养护时间为32h,砷渣最高掺量为34%,固化体抗压强度为13.6MPa,砷毒性浸出浓度为2.4mg·L-1,低于砷毒性浸出浓度国家标准要求限值(5mg·L-1)。(4)通过XRD、SEM、FTIR等手段对含砷废渣固化体组成及结构进行分析可得,固化体物相组成主要为Ca3(AsO4)2、Ca2As2O7、AlAsO4、Ca10Si7As18,砷主要以难溶盐的形式存在,并且填充于地聚物材料的丰富的网状结构中。从而通过物理包裹和化学键合的方式实现含砷废渣的稳定化处理。(5)对含砷废渣固化体耐久性(冻融和硫酸盐侵蚀)进行分析:三种冻融方法冻融后的固化体质量几乎没有变化;15个循环后固化体的抗压强度仍能达到15MPa;同时含砷化合物的毒性浸出随冻融破坏次数的增加而上升,9个循环后超出国家标准。硫酸盐侵蚀对固化体的质量破坏变化不很明显;固化体的抗压强度随着侵蚀次数的增加出现下降的趋势,但是8个循环过后依然大于25MPa;砷的浸出浓度有所上升,但是升高的趋势不明前,且前5个循环能达到国家标准。(6)固化体经济成本分析:用磷渣基地聚物材料固化3.5万吨含砷废渣的原料成本为994.85万元/年,加工制造成本为351.375万元/年,固化成本合理。
[Abstract]:In this paper, the arsenic containing waste residue produced from a smelter in Yunnan Province is taken as the research object to study the arsenic toxicity leaching characteristics of arsenic containing waste residue under different environments. Through single-factor screening experiment and multi-factor orthogonal experiment, the effects of the content of phosphorus slag, fly ash and chemical admixture on the properties of polymer materials were investigated. Polymer materials with excellent mechanical properties were prepared. The mechanical properties and arsenic leaching characteristics of arsenic-containing waste residue solidified with phosphorus-fly ash base polymer under different curing conditions were investigated. Through freeze-thaw experiment and sulfate erosion experiment, the durability of solidified polymer material was preliminarily explored. The results showed that the arsenic leaching concentration of arsenic waste residue varied greatly under different pH conditions. The leaching concentration of arsenic in neutral environment is stable, but still more than 1000mg 路L ~ (-1). Lime admixture can effectively control the leaching concentration of arsenic containing waste slag, but the durability of arsenic containing waste slag after lime treatment is extremely poor, and it is easy to cause secondary pollution because of its storage in natural environment. The leaching concentration of arsenic-containing waste slag is increased when the content of water glass is too high. 2) the phosphorus slag and fly ash in the polymer material are determined by the single factor experiment and the orthogonal experiment of many factors. The optimum content of high calcium ash is phosphorous slag 75, fly ash 15, high calcium ash 10, water glass modulus Mu 1.2, and addition amount 4%, the mechanical properties of the material are the best. The compressive strength is 40.98 MPA when steam curing under atmospheric pressure for 24 h; The polymer materials were characterized by means of XRDX FTIR SEM. The phase composition of the polymer was mainly amorphous, with rich network structure. Its main components are As2O3 and CaF _ 2, and the arsenic content is 14.2.The arsenic toxicity leaching characteristics under different pH conditions are investigated, and the lowest arsenic leaching concentration is 1350mg 路L ~ (-1). The effect of curing time, curing mode and arsenic slag content on the properties of solidified body was investigated. The best curing method was steam curing. The curing time is 32 h, the maximum amount of arsenic slag is 34%, the compressive strength of the solidified body is 13.6 MPA, and the concentration of arsenic toxic leaching is 2.4 mg 路L ~ (-1). The composition and structure of arsenic-containing waste residue were analyzed by means of XRDX SEMX FTIR and other means, which were lower than the national standard limit of arsenic leaching concentration (5 mg 路L -1). The phase composition of the solidified body is mainly Ca3AsO4O2Ca2As2O7AlAsO4AlAsO4Ca10Si7As18.The arsenic mainly exists in the form of insoluble salt. And it is filled in the rich network structure of polymer material. The durability of arsenic-containing waste residue is realized by physical wrapping and chemical bonding. Freeze-thaw and sulfate erosion) analysis: three freeze-thaw methods after freezing and thawing the solidified body mass almost no change; After 15 cycles, the compressive strength of the solidified body can still reach 15 MPA. At the same time, the toxic leaching of arsenic-containing compounds increased with the increase of freeze-thaw failure times, and exceeded the national standard after 9 cycles. The compressive strength of the solidified body decreased with the increase of erosion times, but it was still more than 25 MPA after 8 cycles. The leaching concentration of arsenic increased, but the increasing trend was unknown. And the first five cycles can reach the national standard. 6) the economic cost analysis of curing body: the raw material cost of curing 35,000 tons of arsenic containing waste residue with phosphorous slag base polymer material is nine million nine hundred and forty-eight thousand and five hundred yuan per year. The cost of processing and manufacturing is three million five hundred and thirteen thousand and seven hundred and fifty yuan per year, and the solidification cost is reasonable.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X756;TQ177

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