含砷石膏渣水泥固化及强化机制研究

发布时间：2018-01-26 03:56

本文关键词： 含砷石膏渣水泥固化预煅烧强化机制浸出毒性　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：有色冶金行业在生产铜、镍、铅、锌、锡过程中,使用石灰铁盐法处理的酸性废水,处理后得到含砷石膏渣。大约有将近100万吨含不同金属元素的污泥储藏在安全场中,若不处理直接堆存会污染周围的土地资源,甚至影响地下水资源。一旦人体摄入过量的砷,会影响人类的身体健康。所以,含砷石膏渣污泥亟待进行无害化或资源化处理,意义重大。本文以含砷石膏渣为对象,通过采用氧化与水泥固化/稳定化技术组合,辅以动态毒性评估体系,进行了含砷石膏渣的无害化处理及其机理研究。针对传统水泥固化技术的增容比大、稳定性不强等不足之处,通过改变添加剂的种类(如玻璃粉、高锰酸钾、铁锰氧化物),探寻改善传统水泥固化的强化机制,并且系统讨其影响因子、作用机理。探讨了影响胶凝材料性能的主要工艺参数,借助XRD、SEM等现代测试手段对固化体的水化过程硬化机理和其微观结构进行了分析,获知水泥主要通过物理包裹与形成一定砷酸钙盐成份将含砷石膏渣稳定化,并形成具有一定机械强度的水泥固化体。结果表明:石膏渣的主要成分是CaSO4及其水合物,其中砷的毒性浸出分别是114.06 mg·L-1(GB)以及125.81 mg·L-1(TCLP),超过国家危险废弃物5mg.L-1的标准,属于危险废弃物;经水泥固化含砷污泥后,在28d后,石膏渣添加量30%,砷离子毒性浸出浓度5 mg/L;玻璃粉的加入可以明显的提高强度,但是对于砷离子的吸附能力较差,最优添加量为0.2～5%;石膏渣中的As3+氧化成As5+后再水泥固化后的固化体,比传统固化的效果更好,可满足中国危险废弃物堆放的要求;含砷石膏渣热分解过程伴随着游离水和结晶水的脱除、氢氧化物、碳酸盐、亚砷酸盐和CaSO4的分解,煅烧再固化后的砖体,其浸出液中砷的含量5 mg/L;铁锰氧化物对砷离子有着较强的吸附性能,尤其是对于As5+的吸附效果更好。水泥固化中添加1%的铁锰氧化物砷离子毒性浸出的浓度1 mg/L。经固化/稳定化处理后的含砷石膏渣可以达到国家危险废弃排放标准(5mg/L),本文研究的方案不仅可以解决环境污染问题,而且强化机制可以减少固化过程中水泥的用量,所以还具有一定经济效益。
[Abstract]:The non-ferrous metallurgical industry in the production of copper, nickel, lead, zinc, tin process, acid wastewater treatment using lime ferric salt, obtained after the treatment of arsenic containing gypsum slag. Approximately 1 million tons of sludge containing different metal elements stored in the security field, if not directly stockpiling will pollute the surrounding land, even the influence of groundwater resources. Once the excessive intake of arsenic, will affect the human health. Therefore, the need for resources or harmless treatment, arsenic containing sludge gypsum slag is significant. The arsenic containing gypsum slag as the object, by using oxidation and cement solidification / stabilization technology combined with dynamic toxicity evaluation system. The study on the harmless treatment and mechanism of arsenic containing gypsum slag. According to the traditional Compatibilization of cement solidification technology ratio, stability is not strong and other shortcomings, by changing the types of additives (such as glass powder, Potassium Permanganate, Iron and manganese oxides), to explore the improvement of the traditional curing cement strengthening mechanism and system, and discuss its influencing factors, mechanism of action. The effect of the main process parameters, performance of cementitious materials by means of XRD, SEM and other modern test methods of solidified body hydration hardening mechanism and its microstructure was analyzed, that mainly cement the physical package and the formation of a calcium arsenate arsenic containing ingredients will gypsum slag stabilization, and the formation of solidified cement has certain mechanical strength. The results showed that the main components of gypsum slag is CaSO4 and hydrate, the toxicity of arsenic leaching were 114.06 mg and 125.81 mg L-1 (GB) - L-1 (TCLP) 5mg.L-1, exceeding the national standard of hazardous waste, belong to hazardous waste; by cement solidification of sludge with arsenic, 28d, gypsum slag adding amount of 30%, the leaching toxicity of arsenic ion concentration of 5 mg/L; glass Powdercan Ming To improve the strength significantly, but the arsenic ion adsorption ability is poor, the optimum adding amount was 0.2 ~ 5%; As3+ oxidation in gypsum slag into As5+ after cement curing after curing, better than the traditional curing effect, can meet the requirements Chinese hazardous waste dumps; decomposition process of arsenic containing gypsum slag with heat the removal of free water and crystal water, hydroxide, carbonate, decomposition of arsenite and CaSO4, and then calcined after curing the brick, the content of arsenic in the leaching solution of 5 mg/L; Fe Mn oxides have strong adsorption properties of arsenic ions, especially for the better adsorption effect of As5+ concentration of iron and manganese. Arsenic oxide ion toxicity leaching by adding 1% of cement in 1 mg/L. after solidification / stabilization after the treatment of arsenic containing gypsum slag can reach the national emission standards for hazardous waste (5mg/L), this paper studies the scheme can not only solve the problem of the pollution of the environment, and And the strengthening mechanism can reduce the amount of cement in the curing process, so it also has some economic benefits.

【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】：X758

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