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循环流化床灰中铝的浸出行为及动力学研究 总被引:1,自引:0,他引:1
以煤矸石电厂循环流化床粉煤灰(CFB灰)为原料,研究了CFB灰中Al2O3酸浸出行为的影响因素及其酸浸出过程动力学。试验结果表明:盐酸浓度6 mol/L、酸浸温度110℃、酸浸时间180 min、液固比为4:1,KF加入量为15%,Al2O3的浸出率为68.46%。CFB灰中Al2O3的浸出过程受扩散和化学反应控制,符合典型的"未反应核收缩模型"。其反应动力学方程可用1-(1-α)1/3=k’t来描述,反应表观级数为1.0875,反应活化能为21.186 kJ/mol。 相似文献
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在使用循环流化床(CFB)焚烧技术处置城市生活垃圾过程中,会产生大量垃圾焚烧飞灰(简称CFB灰),它是Cu、Zn、Cr、Pb等重金属离子浸出和二噁英含量超标的危险固废,不经安全处置不能直接填埋或资源化利用。故此,本文研究了热处置对CFB灰用作水泥混合材的改性效果,结果表明:CFB灰直接用作水泥混合材的火山灰活性很低,仅为21.68%;所含少量Al单质的反应会导致水泥浆体膨胀,氯盐和二噁英含量高不符合作为水泥混合材要求;经1200℃,60min热改性后,火山灰活性提高至65.89%,氯离子和二噁英含量降低至1.08%和0.98ng TEQ/kg,当掺量不大于10%时满足制备P·O42.5水泥要求。 相似文献
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以烧结灰水浸渣为原料、酸性硫脲溶液为浸出剂,采用超声强化法研究了超声波功率、颗粒尺寸、浸出时间、硫脲浓度、反应温度对银浸出率的影响,在此基础上采用响应曲面法(RSM)优化设计银浸出实验,获得烧结灰中提银的最佳工艺条件和二阶多项式模型. 结果表明,在超声波功率400 W、颗粒尺寸75~96 ?m、浸出时间90 min、硫脲浓度22 g/L、反应温度50℃条件下,银浸出率的模型预测值为96.15%,实测值为95.7%,相对误差为0.45%,可用该模型预测烧结灰提取银过程. 相似文献
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主要研究了冶炼废渣中铜、锌的浸出,通过对废渣成分的分析选择了氨性浸出,首先通过四因素三水平的正交试验得到了氨性浸出的优化条件:石灰用量5%,碳酸氢铵用量30%,固液质量比为1:4,浸出时间为36 h,铜、锌的浸出率分别为58.6%和42.6%,由正交试验可以看出碳酸氢铵用量为显著因素.然后考察了石灰用量、碳酸氢铵用量、固液比、浸出时间以及氧化剂5个因素对铜锌浸出的影响,优化了氨性浸出的条件,在石灰用量5%,碳酸氢铵用量30%,固液质量比1:4,浸出时间36 h,氧化剂(次氯酸钠)用量6%的条件下铜、锌的浸出率分别为76.4%和63.4%.对同一矿样多次浸出铜、锌浸出率分别达到90.1%和84.1%. 相似文献
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Comparison of fly ash leaching methods 总被引:1,自引:0,他引:1
Ann G. Kim 《Fuel》2009,88(5):926-998
Five leaching methods (serial batch leaching procedure (SBLP), synthetic groundwater leaching procedure (SGLP), mine water leaching procedure (MWLP), 3 TIER integrated framework leaching protocol (3TIER), and toxicity characteristic leaching procedure (TCLP)) were compared using two samples, a class F fly and a class C fly ash. Each method was tested in triplicate, according to the published procedure, and leachate was analyzed for 23 elements. The procedures were compared on the basis of elemental availability, defined as the cumulative elemental release per kg of sample, and the variation in extraction with increased L/S as a surrogate for long term release. Higher availability values were obtained with the SBLP and MWLP, which cover a range of pH’s and 3TIER, which uses EDTA to form soluble complexes. SGLP, a high pH procedure, and TCLP, mildly acidic, generally produced lower availability values. Cumulative elemental extraction as a function of L/S in SBLP, MWLP and 3TIER generally agreed within an order of magnitude. 相似文献
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为研究煤矸石主要污染组分在不同淋溶条件下溶出规律,本研究以辽宁某煤矿煤矸石为实验材料,通过静态淋溶实验,结合XRD、SEM检测技术,综合分析煤矸石中Cl-、总硬度、Cu、Zn等主要污染组分溶出量在不同固液比、pH值、粒径、是否搅动条件下随时间变化的规律.实验结果表明:污染组分溶出量受淋溶条件变化的影响较明显,且在固液比为1:5、pH值为5.3、粒径小于5 mm、间歇性搅动条件下,Cl-和总硬度的溶出量变化较明显;淋溶初期,由于煤矸石表面风化,污染组分溶出速率较大;淋溶过程中,污染组分赋存状态的不同使其溶出效果不同,且由于二次相的形成,胶体和煤矸石中粘土的吸附作用,污染组分溶出量存在一定程度的波动. 相似文献
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较系统地介绍了溶浸采矿法的堆置浸矿法,就地破碎溶浸采矿法,原地溶浸采矿法的国内外应用情况,同时分别阐述了它们的发展方向。 相似文献
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T. A. Lasheen M. E. El-Ahmady H. B. Hassib A. S. Helal 《Frontiers of Chemical Science and Engineering》2013,7(1):95
The processing of molybdenum-uranium ore in a sulfuric acid solution using hydrogen peroxide as an oxidant has been investigated. The leaching temperature, hydrogen peroxide concentration, sulfuric acid concentration, leaching time, particle size, liquid-to-solid ratio and agitation speed all have significant effects on the process. The optimum process operating parameters were: temperature: 95°C; H2O2 concentration: 0.5 M; sulfuric acid concentration: 2.5 M; time: 2 h; particle size: 74 μm, liquid-to-solid ratio: 14 ∶ 1 and agitation speed: 600 rpm. Under these experimental conditions, the extraction efficiency of molybdenum was about 98.4%, and the uranium extraction efficiency was about 98.7%. The leaching kinetics of molybdenum showed that the reaction rate of the leaching process is controlled by the chemical reaction at the particle surface. The leaching process follows the kinetic model 1 ? (1?X )1/3 = kt with an apparent activation energy of 40.40 kJ/mole. The temperature, concentrations of H2O2 and H2SO4 and the mesh size are the main factors that influence the leaching rate. The reaction order in H2SO4 was 1.0012 and in H2O2 it was 1.2544. 相似文献
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为了探索在微生物存在的条件下氧化锰和硫化矿共同浸出的特点,进行了氧化亚铁硫杆菌在好氧和厌氧条件下对FeS2-MnO2-H2SO4体系的催化浸出实验研究。结果表明,在好氧条件和厌氧条件下,氧化亚铁硫杆菌均可以催化FeS2-MnO2-H2SO4体系的浸出。好氧条件下利于FeS2的浸出,浸出36 h时,在MnO2:FeS2质量比为1:1、5:1、6:1时的浸出率分别为:25.34%、82.89%和82.58%。厌氧条件下,利于MnO2的浸出,浸出36 h时,在MnO2:FeS2质量比为1:1、5:1、6:1时的浸出率分别为:87.76%、85.35%和75.09%。浸出机理是氧化亚铁硫杆菌催化铁离子在二价和三价之间的循环转化,根据实验结果提出了好氧和厌氧条件下,FeS2-MnO2-H2SO4体系的两矿反应模型。 相似文献