硫酸法钛白生产企业废副产品污染解析与环境风险评估
发布时间：2018-07-13 21:11
【摘要】：我国硫酸法钛白粉企业每年大约产生1300万吨废酸和13000万吨废水,废水和未利用的废酸混合后经中和处理产生以CaSO4·2H2O为主要成分的钛石膏1700万吨。钛石膏不仅产量大且含有多种重金属杂质(如,Cr、Ni、As、Pb等),其堆置处理除了占用大量的土地,也可能会污染水体和土壤环境,但目前我国并没有对钛石膏进行准确的定性,缺乏相应的处理处置技术和控制管理标准。本文通过文献查阅、专家咨询和实地调研三种方法,从钛白粉生产工艺-废水特征-处理工艺-污泥特征-风险评估全过程切入,明确废酸、废水的产生节点、化学组成、处理方式,以及处理后产生的钛石膏的化学组成、处置现状,并对钛石膏进行危险特性分析和环境风险评估。通过明确钛石膏的性质及对环境的潜在风险,来指导全行业污泥的处理处置,也为国家制定相关管理政策提供理论依据。研究结果表明:(1)目前,硫酸法钛白行业废酸的资源化利用率大幅度提升,已高达52.1%。废酸被成功应用到回用于引发或浸取、制备聚合硫酸铁净水剂、浓缩至45～55%后再利用、制备普钙或硫酸铵肥料等途径,但这些途径各自还是存在局限性,如浓缩耗能较大、聚合硫酸铁及肥料的销路比较有限等。另外,分析比较华北、江浙及攀枝花三个地区对废酸利用的差异发现,江浙地区对废酸的利用最高,高达61.2%,而华北及攀枝花地区的废酸利用率较低,仅分别为25.3%和17.8%。同时,通过对组分分析发现,废酸中含有大量金属盐类,这可能是制约其再利用的主要因素。因此,研究者还应积极开发切实可行的废酸利用技术。(2)通过对酸性废水组分研究发现,其中的有害重金属含量不高,仅为废酸的1/10左右,这有利于其进行净化处理。目前,硫酸法钛白企业采用的废水处理方法都是碱性粉料中和工艺,各企业间的具体流程稍有差别,但均能达到较好的处理效果。处理后的外排水中除Mn2+外其他重金属离子均能满足《污水综合排放标准》(GB 8978-1996)中规定的排放浓度,这可能是由于废水中锰含量最高导致的。(3)目前仍有69.8%的钛石膏采用渣场堆存的方式处置,其综合利用方法有:用作水泥缓凝剂、制备建材砖、制成优质白石膏,但这三种方法都存在一定局限性。另外,分析华北、江浙及攀枝花三个地区对钛石膏综合利用的差异发现,华北及江浙地区对钛石膏的利用率稍高,而攀枝花地区的钛石膏尚无资源化利用。(4)对钛石膏进行危险特性分析发现,其浸出液中重金属含量均没有超过《危险废物鉴别标准浸出毒性鉴别》(GB 5085.3-2007)中规定的限值,且均低于《污水综合排放标准》(GB 8978-1996)中规定的最高允许排放浓度,腐蚀性鉴别pH值也均在标准范围(6～9)之内,因此可初步判定,钛石膏属于Ⅰ类一般工业固体废物,可以参照一般工业固体废物进行处置和管理。(5)对各企业的钛石膏进行环境风险评估发现,地质累积指数法的计算结果中只有企业12钛石膏中的元素Cu处于无-中度污染,内梅罗指数法计算得到的数据中有6家企业存在轻微污染的状况,而潜在生态危害指数法的计算结果表明各企业均是低风险。就评估结果来看,钛石膏对环境的危害应该不是太大,但国家与行业应及时制定钛石膏的统一评判标准,这也有助于钛石膏的处置和利用。
[Abstract]:The titanium dioxide enterprises in China produce about 13 million tons of waste acid and 130 million tons of waste water each year. After the mixing of waste water and unused waste acid, 17 million tons of titanium gypsum are produced by neutralization treatment with CaSO4. 2H2O as the main component. The production of titanium gypsum is large and contains a variety of heavy metal impurities (such as Cr, Ni, As, Pb and so on). The amount of land may also pollute the water and soil environment, but at present, there is no accurate qualitative analysis of titanium gypsum and the lack of corresponding treatment and disposal technology and control management standards in China. Through literature review, expert consultation and field investigation, three methods are used, from the production process of titanium dioxide to the characteristics of the wastewater treatment, the characteristic of the sludge. The whole process of risk assessment is made to clear the waste acid, the production node of the waste water, the chemical composition, the treatment method, the chemical composition of the titanium gypsum produced after treatment, the disposal status, and the hazard analysis and environmental risk assessment of the titanium gypsum. By defining the nature of the titanium gypsum and the potential risk to the environment, it will guide the sludge in the whole industry. The research results show that: (1) at present, the utilization rate of waste acid in the sulphuric acid titanium dioxide industry has been greatly improved, and the waste acid of 52.1%. has been successfully applied to reused and soaked to prepare polymeric ferric sulfate purifier, and then reused after concentration to 45 to 55%. Ammonium sulphate fertilizer and other ways, but these ways are still limited, such as concentrated energy consumption, and limited distribution of polymeric ferric sulfate and fertilizer. In addition, the analysis and comparison of the use of waste acid in three areas in North China, Jiangsu, Zhejiang and Panzhihua found that the use of waste acid in Jiangsu and Zhejiang areas is the highest, up to 61.2%, and North China and Panzhihua land. The utilization rate of waste acid in the area is low, only 25.3% and 17.8%. respectively. Through the analysis of the components, it is found that the waste acid contains a large amount of metal salts, which may be the main factor restricting its reuse. Therefore, the researchers should also actively develop the practical waste acid utilization technology. (2) the harmful weight of the acid waste water components is found by the study of the acid wastewater components. The metal content is not high, only about 1/10 of waste acid, which is beneficial to its purification treatment. At present, the wastewater treatment methods used by titanium dioxide in the sulfuric acid process are alkaline powder neutralization process, and the specific processes between various enterprises are slightly different, but all of them can achieve better treatment effect. Other heavy metal ions in the external drainage in the post process are in addition to the other heavy metal ions. The discharge concentration stipulated in the comprehensive discharge standard of sewage (GB 8978-1996) can be satisfied, which may be due to the highest manganese content in the wastewater. (3) there are still 69.8% of the titanium gypsum used in the process of slag storage. The comprehensive utilization methods are used as cement retarder, building materials brick, and making high quality white gypsum, but these three methods In addition, the analysis of the comprehensive utilization of titanium gypsum in three regions of North China, Jiangsu, Zhejiang and Panzhihua found that the utilization rate of titanium gypsum was slightly higher in North China and Jiangsu and Zhejiang provinces, while the titanium gypsum in Panzhihua area had no resource utilization. (4) analysis of the dangerous characteristics of titanium gypsum found that the content of heavy metals in the leaching solution was all The limit values specified in the identification of hazardous waste identification standard leaching toxicity (GB 5085.3-2007) are not more than the maximum allowable discharge concentration specified in the integrated wastewater discharge standard (GB 8978-1996), and the pH value of the corrosivity identification is also within the standard range (6~9). Therefore, it can be preliminarily determined that the titanium gypsum belongs to the type I general industrial solid waste. Materials can be treated and managed according to the general industrial solid waste. (5) the environmental risk assessment of titanium gypsum in various enterprises shows that only the element Cu in the enterprise 12 titanium gypsum has no moderate pollution in the calculation results of the geological accumulation index method, and there are 6 enterprises in the data obtained by Nemero index method. The results of the potential ecological hazard index method show that all enterprises are low risk. As to the evaluation results, the hazard of titanium gypsum to the environment should not be too large, but the state and industry should make the unified evaluation standard of titanium gypsum in time, which will also help the disposal and utilization of titanium gypsum.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X788;X82
[Abstract]:The titanium dioxide enterprises in China produce about 13 million tons of waste acid and 130 million tons of waste water each year. After the mixing of waste water and unused waste acid, 17 million tons of titanium gypsum are produced by neutralization treatment with CaSO4. 2H2O as the main component. The production of titanium gypsum is large and contains a variety of heavy metal impurities (such as Cr, Ni, As, Pb and so on). The amount of land may also pollute the water and soil environment, but at present, there is no accurate qualitative analysis of titanium gypsum and the lack of corresponding treatment and disposal technology and control management standards in China. Through literature review, expert consultation and field investigation, three methods are used, from the production process of titanium dioxide to the characteristics of the wastewater treatment, the characteristic of the sludge. The whole process of risk assessment is made to clear the waste acid, the production node of the waste water, the chemical composition, the treatment method, the chemical composition of the titanium gypsum produced after treatment, the disposal status, and the hazard analysis and environmental risk assessment of the titanium gypsum. By defining the nature of the titanium gypsum and the potential risk to the environment, it will guide the sludge in the whole industry. The research results show that: (1) at present, the utilization rate of waste acid in the sulphuric acid titanium dioxide industry has been greatly improved, and the waste acid of 52.1%. has been successfully applied to reused and soaked to prepare polymeric ferric sulfate purifier, and then reused after concentration to 45 to 55%. Ammonium sulphate fertilizer and other ways, but these ways are still limited, such as concentrated energy consumption, and limited distribution of polymeric ferric sulfate and fertilizer. In addition, the analysis and comparison of the use of waste acid in three areas in North China, Jiangsu, Zhejiang and Panzhihua found that the use of waste acid in Jiangsu and Zhejiang areas is the highest, up to 61.2%, and North China and Panzhihua land. The utilization rate of waste acid in the area is low, only 25.3% and 17.8%. respectively. Through the analysis of the components, it is found that the waste acid contains a large amount of metal salts, which may be the main factor restricting its reuse. Therefore, the researchers should also actively develop the practical waste acid utilization technology. (2) the harmful weight of the acid waste water components is found by the study of the acid wastewater components. The metal content is not high, only about 1/10 of waste acid, which is beneficial to its purification treatment. At present, the wastewater treatment methods used by titanium dioxide in the sulfuric acid process are alkaline powder neutralization process, and the specific processes between various enterprises are slightly different, but all of them can achieve better treatment effect. Other heavy metal ions in the external drainage in the post process are in addition to the other heavy metal ions. The discharge concentration stipulated in the comprehensive discharge standard of sewage (GB 8978-1996) can be satisfied, which may be due to the highest manganese content in the wastewater. (3) there are still 69.8% of the titanium gypsum used in the process of slag storage. The comprehensive utilization methods are used as cement retarder, building materials brick, and making high quality white gypsum, but these three methods In addition, the analysis of the comprehensive utilization of titanium gypsum in three regions of North China, Jiangsu, Zhejiang and Panzhihua found that the utilization rate of titanium gypsum was slightly higher in North China and Jiangsu and Zhejiang provinces, while the titanium gypsum in Panzhihua area had no resource utilization. (4) analysis of the dangerous characteristics of titanium gypsum found that the content of heavy metals in the leaching solution was all The limit values specified in the identification of hazardous waste identification standard leaching toxicity (GB 5085.3-2007) are not more than the maximum allowable discharge concentration specified in the integrated wastewater discharge standard (GB 8978-1996), and the pH value of the corrosivity identification is also within the standard range (6~9). Therefore, it can be preliminarily determined that the titanium gypsum belongs to the type I general industrial solid waste. Materials can be treated and managed according to the general industrial solid waste. (5) the environmental risk assessment of titanium gypsum in various enterprises shows that only the element Cu in the enterprise 12 titanium gypsum has no moderate pollution in the calculation results of the geological accumulation index method, and there are 6 enterprises in the data obtained by Nemero index method. The results of the potential ecological hazard index method show that all enterprises are low risk. As to the evaluation results, the hazard of titanium gypsum to the environment should not be too large, but the state and industry should make the unified evaluation standard of titanium gypsum in time, which will also help the disposal and utilization of titanium gypsum.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X788;X82
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