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磷矿中稀土浸出的动力学研究 总被引:4,自引:4,他引:0
研究了硝酸浸出磷矿中稀土的动力学,考察了温度、浓度、粒度对稀土浸出率的影响。结果表明,提高温度和浓度、减小粒度均能提高稀土浸出率。浸出过程符合未反应收缩核模型,受界面化学反应控制,表观活化能为70.6 kJ/mol,表观反应级数为0.83级。 相似文献
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针对现行主流氢氧化钠和碳酸钠浸出低品位白钨矿存在浸出剂用量大,浸出率低的弊端,提出磷酸钠-氢氧化钠-氟化钙协同高效浸出低品位白钨矿的新工艺。氟化钙作为固体氟源,在浸出过程中首先发生溶解并释放出游离的氟离子,再参与白钨矿的浸出反应生成氟磷酸钙沉淀。因此,氟化钙的溶解速率对白钨矿浸出速率有较大影响。文章使用等浸出率法,对磷酸钠-氢氧化钠分解氟化钙的动力学进行了研究。考查了浸出温度及磷酸钠浓度对氟化钙浸出速率的影响。结果表明:氟化钙浸出速率受浸出温度影响很大,而受磷酸钠浓度影响相对较小,浸出反应表观活化能为134.57 kJ/mol,表观反应级数为0.92,氟化钙浸出过程受化学反应控制。研究结果对低品位白钨矿浸出过程强化具有一定的理论指导作用。 相似文献
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针对攀枝花某企业产出的钒渣,以碳酸氢铵水溶液为浸出剂,研究了从钒渣中浸出钒的宏观动力学,考察了搅拌速度、反应温度、浸出剂质量浓度和颗粒粒度对钒浸出率的影响。结果表明:钒浸出过程遵循"未反应收缩核模型",反应主要受固体产物层扩散控制;钒浸出率随液固体积质量比增大、搅拌速度增大、反应温度升高及浸出剂质量浓度增大、颗粒粒度减小而提高。根据试验数据,建立了宏观动力学模型,求得反应表观活化能E=18.0kJ/mol,指前因子A=0.713,确立了宏观动力学方程。 相似文献
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研究了以盐酸-磷酸络合体系浸出人造白钨矿制备磷钨杂多酸。试验结果表明:以盐酸-磷酸络合浸出人造白钨矿,盐酸初始浓度、反应温度、钨磷物质的量比、搅拌速度等因素对钨浸出率均有显著影响;浸出产物为H3[PW12O40],反应过程受界面化学反应控制,表观活化能Ea=60.652kJ/mol;在HCl初始浓度0.72mol/L、反应温度50℃、钨磷物质的量比7/1、搅拌强度600r/min条件下,钨浸出率在98%以上。 相似文献
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研究了含锌废渣及贫杂锌矿在碱浸过程中的动力学。结果表明,含锌废渣(ZnO)在碱溶液中的浸出过程符合关系式1-(1-η)13=kt,表观活化能为49.22 kJ/mol,说明浸出过程受化学控制;贫杂锌矿(ZnCO3)在碱溶液中的浸出过程可分为两段,在开始段时间内,1-(2/3)η-(1-η)2/3与浸出时间呈直线关系,活化能为19.95 kJ/mol;而在6 min以后则是1-(1-η)13与浸出时间呈直线关系,活化能为46.54 kJ/mol。说明在开始时间段内是受内扩散控制,而随后的浸出过程是受化学反应控制。 相似文献
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Kinetics of manganese reduction leaching from weathered rare-earth mud with sodium sulfite 总被引:3,自引:0,他引:3
R. Chi G. Zhu S. Xu J. Tian J. Liu Z. Xu 《Metallurgical and Materials Transactions B》2002,33(1):41-46
The kinetics of manganese reduction leaching in an acidic medium from a weathered rare-earth mud (WREM) were investigated.
Using sodium sulfite as a reductant, the effect of reaction temperature, mechanical agitation rate, sulfuric acid dosage,
and feed particle size on leaching kinetics were examined. The leaching process can be described by the shrinking-core model.
An apparent activation energy of 11.5 kJ/mol for manganese reduction leaching is estimated. The diffusion of reactants and
leaching products through a porous ore matrix was found to be the rate-limiting step. An empirical equation relating the manganese
leaching rate constant with feed-particle size and leaching temperature was established. It was found that the smaller the
feed-particle size or the higher the leaching temperature, the faster the leaching proceeds, as anticipated. The kinetic process
exhibited a self-catalysis characteristic of Mn2+ in the mud. This finding suggests that Mn(III,IV) in the mud was rapidly reduced to Mn2+ during the initial stage of leaching. 相似文献
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J. L. Clements K. A. Prisbrey P. R. Taylor 《Metallurgical and Materials Transactions B》1980,11(2):301-307
The selective leaching of uranium, vanadium, and phosphorus from phosphate ore may be useful in by-product recovery. Experimental
results have shown that it is possible to preferentially remove uranium from phosphate ore using dilute HCl (0.05 M). 93 pct
of the uranium is leached within 90 min, leaving 94 pct of the phosphorus and 82 pct of the vanadium unattacked. Phosphorus
may then be removed by increasing the pH. The apparent activation energies and orders for the leaching reactions were found.
For uranium, the apparent order with respect to H+ is 1.05 and the apparent activation energy is 7750 J. The apparent order for the leaching of the vanadium minerals with respect
to H+ is 1.93 and the apparent activation energy is 12800 J. The phosphorus reaction has an apparent order, with respect to H+, of 1.98 and an apparent activation energy of 10200 J. The uranium readsorbs at longer times. The readsorption reaction is
a function of temperature, particle size, and H+ concentration. Two methods of selectivity analysis were used in the analysis of the data-end point analysis and initial rate
analysis. 相似文献
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石煤提钒碱浸过程动力学研究 总被引:5,自引:0,他引:5
研究了石煤空白焙烧料NaOH溶液浸出过程中液固比、NaOH溶液初始浓度、反应搅拌速率、矿石粒径、温度对浸出速率的影响,确定了石煤提钒碱浸过程动力学方程式,计算了反应的表观活化能.结果表明:液固比、反应搅拌速率对浸出速率的影响不大,NaOH溶液初始浓度、矿石粒径、浸出温度对浸出速率的影响显著;V2O5的浸出动力学适用于收缩未反应芯模型,浸出反应服从化学反应控制过程;根据Arrhenius公式,使用曲线拟合法,近似求得该反应表观活化能约为58.5 kJ·mol-1,进一步表明该反应属于化学反应控制. 相似文献