【摘要】：我國(guó)硫酸法鈦白粉企業(yè)每年大約產(chǎn)生1300萬(wàn)噸廢酸和13000萬(wàn)噸廢水,廢水和未利用的廢酸混合后經(jīng)中和處理產(chǎn)生以CaSO4·2H2O為主要成分的鈦石膏1700萬(wàn)噸。鈦石膏不僅產(chǎn)量大且含有多種重金屬雜質(zhì)(如,Cr、Ni、As、Pb等),其堆置處理除了占用大量的土地,也可能會(huì)污染水體和土壤環(huán)境,但目前我國(guó)并沒(méi)有對(duì)鈦石膏進(jìn)行準(zhǔn)確的定性,缺乏相應(yīng)的處理處置技術(shù)和控制管理標(biāo)準(zhǔn)。本文通過(guò)文獻(xiàn)查閱、專家咨詢和實(shí)地調(diào)研三種方法,從鈦白粉生產(chǎn)工藝-廢水特征-處理工藝-污泥特征-風(fēng)險(xiǎn)評(píng)估全過(guò)程切入,明確廢酸、廢水的產(chǎn)生節(jié)點(diǎn)、化學(xué)組成、處理方式,以及處理后產(chǎn)生的鈦石膏的化學(xué)組成、處置現(xiàn)狀,并對(duì)鈦石膏進(jìn)行危險(xiǎn)特性分析和環(huán)境風(fēng)險(xiǎn)評(píng)估。通過(guò)明確鈦石膏的性質(zhì)及對(duì)環(huán)境的潛在風(fēng)險(xiǎn),來(lái)指導(dǎo)全行業(yè)污泥的處理處置,也為國(guó)家制定相關(guān)管理政策提供理論依據(jù)。研究結(jié)果表明:(1)目前,硫酸法鈦白行業(yè)廢酸的資源化利用率大幅度提升,已高達(dá)52.1%。廢酸被成功應(yīng)用到回用于引發(fā)或浸取、制備聚合硫酸鐵凈水劑、濃縮至45～55%后再利用、制備普鈣或硫酸銨肥料等途徑,但這些途徑各自還是存在局限性,如濃縮耗能較大、聚合硫酸鐵及肥料的銷路比較有限等。另外,分析比較華北、江浙及攀枝花三個(gè)地區(qū)對(duì)廢酸利用的差異發(fā)現(xiàn),江浙地區(qū)對(duì)廢酸的利用最高,高達(dá)61.2%,而華北及攀枝花地區(qū)的廢酸利用率較低,僅分別為25.3%和17.8%。同時(shí),通過(guò)對(duì)組分分析發(fā)現(xiàn),廢酸中含有大量金屬鹽類,這可能是制約其再利用的主要因素。因此,研究者還應(yīng)積極開(kāi)發(fā)切實(shí)可行的廢酸利用技術(shù)。(2)通過(guò)對(duì)酸性廢水組分研究發(fā)現(xiàn),其中的有害重金屬含量不高,僅為廢酸的1/10左右,這有利于其進(jìn)行凈化處理。目前,硫酸法鈦白企業(yè)采用的廢水處理方法都是堿性粉料中和工藝,各企業(yè)間的具體流程稍有差別,但均能達(dá)到較好的處理效果。處理后的外排水中除Mn2+外其他重金屬離子均能滿足《污水綜合排放標(biāo)準(zhǔn)》(GB 8978-1996)中規(guī)定的排放濃度,這可能是由于廢水中錳含量最高導(dǎo)致的。(3)目前仍有69.8%的鈦石膏采用渣場(chǎng)堆存的方式處置,其綜合利用方法有:用作水泥緩凝劑、制備建材磚、制成優(yōu)質(zhì)白石膏,但這三種方法都存在一定局限性。另外,分析華北、江浙及攀枝花三個(gè)地區(qū)對(duì)鈦石膏綜合利用的差異發(fā)現(xiàn),華北及江浙地區(qū)對(duì)鈦石膏的利用率稍高,而攀枝花地區(qū)的鈦石膏尚無(wú)資源化利用。(4)對(duì)鈦石膏進(jìn)行危險(xiǎn)特性分析發(fā)現(xiàn),其浸出液中重金屬含量均沒(méi)有超過(guò)《危險(xiǎn)廢物鑒別標(biāo)準(zhǔn)浸出毒性鑒別》(GB 5085.3-2007)中規(guī)定的限值,且均低于《污水綜合排放標(biāo)準(zhǔn)》(GB 8978-1996)中規(guī)定的最高允許排放濃度,腐蝕性鑒別pH值也均在標(biāo)準(zhǔn)范圍(6～9)之內(nèi),因此可初步判定,鈦石膏屬于Ⅰ類一般工業(yè)固體廢物,可以參照一般工業(yè)固體廢物進(jìn)行處置和管理。(5)對(duì)各企業(yè)的鈦石膏進(jìn)行環(huán)境風(fēng)險(xiǎn)評(píng)估發(fā)現(xiàn),地質(zhì)累積指數(shù)法的計(jì)算結(jié)果中只有企業(yè)12鈦石膏中的元素Cu處于無(wú)-中度污染,內(nèi)梅羅指數(shù)法計(jì)算得到的數(shù)據(jù)中有6家企業(yè)存在輕微污染的狀況,而潛在生態(tài)危害指數(shù)法的計(jì)算結(jié)果表明各企業(yè)均是低風(fēng)險(xiǎn)。就評(píng)估結(jié)果來(lái)看,鈦石膏對(duì)環(huán)境的危害應(yīng)該不是太大,但國(guó)家與行業(yè)應(yīng)及時(shí)制定鈦石膏的統(tǒng)一評(píng)判標(biāo)準(zhǔn),這也有助于鈦石膏的處置和利用。
[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.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X788;X82

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