本文選題：重金屬　切入點(diǎn)：尾礦　出處：《陜西師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：我國(guó)仍處于城鎮(zhèn)化、工業(yè)化的快速發(fā)展時(shí)期,每天都在消耗大量的礦物資源,礦物資源經(jīng)過(guò)選礦分選后會(huì)產(chǎn)生大量的尾礦,而尾礦的長(zhǎng)期堆積造成的重大事故屢見不鮮,使我國(guó)經(jīng)濟(jì)和生態(tài)環(huán)境遭受了重大威脅。近年來(lái),我國(guó)出臺(tái)了大量與尾礦資源化、最小化和無(wú)害化相關(guān)的政策,特別是《尾礦的處置、管理及資源化示范工程》項(xiàng)目計(jì)劃的出臺(tái),象征著我國(guó)已把尾礦的無(wú)害化處理和回收再利用作為新世紀(jì)的重中之重。目前,我國(guó)礦產(chǎn)資源開采產(chǎn)生的尾礦帶來(lái)的環(huán)境污染問(wèn)題主要表現(xiàn)為多重金屬的復(fù)合污染。國(guó)內(nèi)外針對(duì)去除土壤中污染重金屬已做了大量研究,而關(guān)于對(duì)尾礦中的污染重金屬的無(wú)害化處理研究甚少,在眾多的治理措施中化學(xué)淋洗法因其操作簡(jiǎn)單、速率快、效率高和成本適中等優(yōu)點(diǎn)而被廣大學(xué)者所青睞。本研究選用硝酸、鹽酸、乙二胺四乙酸和氯化鐵四種淋洗劑,選取單一淋洗劑淋洗和兩種淋洗劑復(fù)合淋洗的方法,以陜西省商洛市某選礦廠尾礦庫(kù)采集的黃金尾礦為研究對(duì)象,尋求單一淋洗劑的最優(yōu)淋洗條件和最佳單一淋洗劑,以及最佳復(fù)合淋洗劑和復(fù)合淋洗劑的最佳濃度、液固比、淋洗時(shí)間等淋洗條件。采用HF+HClO4+HNO3消解分析測(cè)定尾礦中重金屬的含量,通過(guò)BCR四步連續(xù)提取法分析了重金屬的乙酸可提取態(tài)、可還原態(tài)、可氧化態(tài)和殘?jiān)鼞B(tài)四種形態(tài)的具體含量,尋求最佳的淋洗劑從而能夠在實(shí)踐中高效地對(duì)尾礦進(jìn)行無(wú)害化處理。結(jié)果表明：(1)金礦石尾礦中重金屬Pb、Co、Ni、Sr、Cu、As的含量分別為70.00、47.25、40.9、315.25、41.65和1930.25 mg/kg,其中,As的含量是陜西省背景值的173倍。尾礦中重金屬Pb、Ni、Cu、As主要是以殘?jiān)鼞B(tài)的形式存在,其含量分別為46.35%、47.07%、53.43%、73.43%；Co以可還原態(tài)為主,含量為32.09%,其次是殘?jiān)鼞B(tài)含量為31.34%，，其乙酸提取態(tài)和可氧化態(tài)含量分別為21.31%和15.26%；Sr的殘?jiān)鼞B(tài)含量較低,僅為5.47%,Sr主要是以乙酸提取態(tài)和可還原態(tài)存在,分別占到57.54%和36.13%。形態(tài)分析法表明,Co、Sr的殘?jiān)鼞B(tài)含量低,生物可利用性高,遷移轉(zhuǎn)化能力強(qiáng)；Pb、Ni、Cu的殘?jiān)鼞B(tài)含量與有效態(tài)含量相當(dāng),生物可利用性較高,遷移轉(zhuǎn)化能力較強(qiáng)；As的殘?jiān)鼞B(tài)含量很高,生物活性弱,較為穩(wěn)定。(2)四種單一淋洗劑對(duì)尾礦的最優(yōu)濃度、最佳固液比、最佳淋洗時(shí)間、淋洗次數(shù)如下：HN03,1mol/L,15:1,16h,1次；HNO3在最佳淋洗條件下對(duì)重金屬As、Cu、Ni、 Pb、Co、Sr的淋洗率分別為27.77%、39.80%、24.57%、26.87%、20.89%、65.80%。HCl,2mol/L,15:1,6h,1次；HCl在最佳淋洗條件下對(duì)重金屬As、Cu, Ni, Pb, Co, Sr的淋洗率分別為44.23%、45.29%、28.57%、31.54%、18.48%、56.67%。EDTA, 0.1mol/L,10:1,6h,2次；EDTA在最佳淋洗條件下對(duì)重金屬As、Cu、Ni、Pb、Co、Sr的淋洗率分別為4.31%、22.05%、9.22%、14.44%、23.61%、42.62%。FeCl3,0.5mol/L,10:1,12h, FeCl3在最佳淋洗條件下對(duì)重金屬As、Cu、Ni、Pb、Co、Sr的淋洗率分別為40.83%、68.69%、13.64%、63.97%、51.24%、69.36%。(3)綜合分析五種復(fù)合淋洗劑HCl-EDTA、HNO3-EDTA、HCl-FeCl3、 HNO3-FeCl3、EDTA-FeCl3對(duì)尾礦中六種重金屬As、Cu、Ni、Pb、Co、Sr的淋洗效果,得出五種復(fù)合淋洗劑的淋洗效率都遠(yuǎn)比單一淋洗劑鹽酸、硝酸、氯化鐵和乙二胺四乙酸的淋洗率要高,復(fù)合淋洗劑對(duì)重金屬的淋洗率隨單一淋洗劑鹽酸、硝酸、氯化鐵和乙二胺四乙酸濃度的升高而增高。比較五種復(fù)合淋洗劑對(duì)重金屬的淋洗效果可知,復(fù)合淋洗劑HCl-FeCl3對(duì)尾礦中Cu的淋洗效率優(yōu)于其他復(fù)合淋洗劑；復(fù)合淋洗劑HCl-FeCl3和HNO3-FeCl3對(duì)As的淋洗效率較為接近且優(yōu)于其他復(fù)合淋洗劑；復(fù)合淋洗劑HCl-FeCl3和EDTA-FeCl3對(duì)Ni的淋洗效率較為接近且優(yōu)于其他復(fù)合淋洗劑；復(fù)合淋洗劑HCl-FeCl3和HNO3-FeCl3對(duì)Sr的淋洗效率較為接近且優(yōu)于其他復(fù)合淋洗劑；復(fù)合淋洗劑HCl-FeCl3、HNO3-FeCl3和EDTA-FeCl3對(duì)Co的淋洗效率較為接近且優(yōu)于其他復(fù)合淋洗劑；復(fù)合淋洗劑HCl-FeCl3、 HNO3-FeCl3和EDTA-FeCl3對(duì)Pb的淋洗效率較為接近且優(yōu)于其他復(fù)合淋洗劑。由上可知,復(fù)合淋洗劑都對(duì)As、Cu、Ni、Pb、Co、Sr有較高的淋洗率且遠(yuǎn)高于單一淋洗劑對(duì)重金屬的淋洗率,其中,復(fù)合淋洗劑HCl-FeCl3對(duì)六種重金屬As、Cu、 Ni、Pb、Co、Sr都有較高的淋洗效果且優(yōu)于其他復(fù)合淋洗劑。復(fù)合淋洗劑HCl-FeCl3對(duì)尾礦進(jìn)行淋洗的最佳濃度、最佳固液比、最佳淋洗時(shí)間、最佳淋洗次數(shù)如下：HC1,0.2mol/L, FeCl3, 1.0mol/L,6:1,6h,3次;HCl-FeCl3在最佳淋洗條件下對(duì)重金屬As、Cu、Ni、Pb、Co、Sr的淋洗率分別為42.37%、76.18%、67.36%、78.91%、68.13%、79.04%。
[Abstract]:China is still in the period of rapid development of urbanization, industrialization, every day to consume a large amount of mineral resources, mineral resources after dressing after sorting will produce large amounts of tailings and tailings caused by long-term accumulation of major accidents It is often seen. to make the economy of our country, and the ecological environment suffered a major threat. In recent years, China promulgated a large number of tailings, minimization and harmless related policies, especially the "tailings disposal demonstration project management and resource project > plan, a symbol of our country has put the harmless treatment and recycling of tailings re-use as priority among priorities in the new century. At present, the problem of environmental pollution tailing exploitation of mineral resources in China have brought the main performance for the combined pollution of heavy metals. Many domestic and foreign to the removal of soil heavy metal pollution has done a lot of research, and on the heavy pollution of tailings in the metal Harmless little research in many control measures of chemical leaching method because of its simple operation, fast speed, high efficiency and low cost and is favored by the majority of scholars. This study used nitric acid, hydrochloric acid, EDTA and ferric chloride and four kinds of leaching agent, method of selecting a single with the eluent and two kinds of leaching agent leaching of the gold tailings in Shangluo city of Shaanxi Province, a concentrator tailings collected as the research object, the optimal elution conditions for single elutriant and single best eluant, and the optimal concentration of the best compound leaching agent and compound leaching agent, liquid-solid ratio, leaching leaching time. Using HF+HClO4+HNO3 digestion determination heavy metals in the tailings, through the BCR four step sequential extraction analysis of heavy metals in the acetic acid extractable, reducible, specific content of four kinds of oxidation state and residual state, In order to seek the best eluent in practice efficiently for tailings harmless treatment. The results showed that: (1) gold ore tailings, heavy metals of Pb, Co, Ni, Sr, Cu, As were 70.00,47.25,40.9315.25,41.65 and 1930.25 mg/kg, among them, the content of As is 173 times the background value in Shaanxi province. The heavy metals of Pb, Cu, As and Ni in the tailings, mainly exists in the form of residua, the contents were 46.35%, 47.07%, 53.43%, 73.43%; Co in reducible, content is 32.09%, followed by the residue content is 31.34%, the acetic acid extractable and oxidable contents were 21.31% and 15.26%; residual content of Sr is relatively low, only 5.47%, Sr is mainly in acid extractable and reducible fraction, respectively accounted for 57.54% and 36.13%. morphological analysis showed that the Co residue content of Sr is low, high bioavailability, migration and transformation ability; Pb, Ni, Cu. A content and available content, high bioavailability, migration and transformation ability; the residual content of As is very high, weak biological activity, relatively stable. (2) the optimal concentration of four kinds of single elutriant of tailings, the optimal solid-liquid ratio, optimum leaching time, leaching times are as follows: HN03,1mol/L, 15:1,16h HNO3, 1 times; in the best leaching of heavy metals As, Cu, Ni, Pb, Co, Sr leaching rate were 27.77%, 39.80%, 24.57%, 26.87%, 20.89%, 65.80%.HCl, 2mol/L, 15:1,6h, 1; HCl is As, the optimum leaching conditions heavily in Cu, Ni, Pb. Co Sr, the leaching rates were 44.23%, 45.29%, 28.57%, 31.54%, 18.48%, 56.67%.EDTA, 0.1mol/L, 10:1,6h, 2; EDTA in the best leaching of heavy metals As, Cu, Ni, Pb, Co, Sr leaching rate were 4.31%, 22.05%, 9.22%, 14.44%, 23.61%, 42.62%.FeCl3,0.5mol/L, 10:1,12h FeCl3, in the best leaching conditions The heavy metals of As, Cu, Ni, Pb, Co, Sr leaching rate were 40.83%, 68.69%, 13.64%, 63.97%, 51.24%, 69.36%. (3) comprehensive analysis of five kinds of compound leaching agent HCl-EDTA, HNO3-EDTA, HCl-FeCl3, HNO3-FeCl3, EDTA-FeCl3 of six kinds of heavy metals in the tailings of As, Cu, Ni, Pb, Co. The results of leaching of Sr, the leaching efficiency of five kinds of composite elutriant are far more than a single elutriant of hydrochloric acid, nitric acid, ferric chloride and EDTA leaching rate to be high, the composite leaching of heavy metal leaching rate with single drench lotion hydrochloric acid, nitric acid, ferric chloride and ethylene increased two amine four acetic acid concentration increased five. For the leaching effect of compound leaching agent for heavy metals, composite leaching leaching efficiency of HCl-FeCl3 is better than Cu in other tailings drench lotion; compound leaching agent HCl-FeCl3 and HNO3-FeCl3 leaching efficiency of As is closer and better than other drench drench lotion; HCl-FeCl3 and EDTA-FeCl3 leaching efficiency of lotion is close to Ni and better than the other composite eluant; compound leaching agent HCl-FeCl3 and HNO3-FeCl3 leaching efficiency of Sr is closer and better than the other composite eluant; compound leaching agent HCl-FeCl3, HNO3-FeCl3 and EDTA-FeCl3 leaching efficiency of Co is closer and better than the other composite eluant; compound leaching agent HCl-FeCl3 EDTA-FeCl3, HNO3-FeCl3 and Pb on leaching efficiency is closer and better than the other. It is the compound spray lotion, compound leaching agent of As, Cu, Ni, Pb, Co, Sr have higher leaching rate and much higher than that of single elutriant of heavy metal leaching rate, the eluent of six kinds of HCl-FeCl3 composite Cu, Ni, heavy metals As, Pb, Co, Sr have high leaching effect and better than the other composite eluant. The best concentration of compound leaching agent HCl-FeCl3 for leaching tailings, the optimal solid-liquid ratio, the most The best eluent time and the best eluent times are as follows: HC1,0.2mol/L, FeCl3, 1.0mol/L, 6:1,6h, 3 times; HCl-FeCl3 under the best leaching conditions, the leaching rates of heavy metals As, Cu, Ni, Pb, Co and Sr are 42.37%, 76.18%, 67.36%, 78.91%, 68.13%, respectively.

【學(xué)位授予單位】：陜西師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X753

【引證文獻(xiàn)】

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