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61.
M. TCHOUMOU M. ROYNETTE 《中国有色金属学会会刊》2007,17(2):423-428
The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena 〉 sphalerite 〉 chalcopyrite. 相似文献
62.
During bio-oxidation of sulfides, the chemical state change of sulfur is a complex and key factor. It is not only an indicator of the extent and intensity of the bio-oxidation, but also controls the property of bio-leaching medium and the period of oxidation. The chemical state of sulfur in sulfides oxidized by leaching bacteria was studied with XPS. Sulfide minerals in the arsenic-bearing gold concentrate consist of pyrite, arsenopyrite, chalcopyrite, galena, sphalerite and so on. In order to probe the pattern of the chemical state change of sulfur in the bio-oxidation residue of arsenic-bearing gold concentrate, the structure of the grains, and the surface nature of the residue, XPS test was carried out through different sputtering duration. The study of XPS clearly shows that: sulfides is progressively oxidized from the surface of minerals to the core by leaching bacteria; the chemical valence of sulfur changes from S^2- or [S2]^2- to [SO4]^2- ; sulfur in the core is in a reduction state, S^2- or [S2]^2- , but exists in an oxidation state S^6 on the surface; due to the chemical state change of sulfur, mineral phase of the bio-oxidation residue is also changed(sulfides inside, while sulfates outside); the layered structure is found in the grains of the bio-oxidation residue. 相似文献
63.
氯化物介质矿浆电解法浸出硫化铜精矿 总被引:3,自引:0,他引:3
研究了在FeCl3HClNaCl体系中直接电解浸出硫化铜精矿矿浆制取铜粉的工艺条件及机理。试验表明,在阳极初始溶液含Fe3+60g/L、HCl30g/L、NaCl150g/L,阴阳极电流密度分别为350和600A/m2,100℃的条件下浸出5h,可获得铜浸出率98.8%、渣含铜0.34%、铜粉纯度97.5%的结果;Fe3+浓度是影响铜浸出率最显著的因素,阳极上发生的主要反应是Fe2+的氧化;元素硫产生的机理是酸直接分解黄铜矿生成H2S,H2S溶解后再被Fe3+氧化。 相似文献
64.
A novel fluidized-bed reactor was designed and installed for bloleaching in a semi-continuous way, by which a process for biuleaching-cyanidation of Jinya refractory gold arsenical concentrate was studied. The arsenic extraction rate reaches 82.5 % after 4-day batch biooxidation of the concentrate under the optimized condition of pH 2.0, ferric ion concentration 6.Sg/L and pulp concentration 10%. And leached rate of gold in the following cyanida.tion is over 90%. The parameters of three series fluidized-bed reactors exhibit stability during the semi-continuous bioleaching of the concentrate.Armmic in the concentrate can be got rid of 91% after 6-day leaching. Even after 4 days, 82% of arsenic extraction rate was still obtained. The recovery rates of gold are 92 % and 87.5 % respectively in cyaniding the above bioleached residues.The results will provide a base for further commercial production of gold development. 相似文献
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66.
朴素贝叶斯由于条件独立性假设使其分类效果不明显,同时在处理海量数据时缺乏灵活性。针对以上情况,提出一种基于动态约简的增量贝叶斯分类算法。算法首先利用(F-λ)广义动态约简计算出数据集的核属性,然后根据训练集的先验信息构造分类器对测试实例进行分类,最后利用类置信度进行选择性增量学习,增强处理增量数据的能力。实验结果表明,该算法在处理属性少的小量数据时,分类效果有一定的改善,在处理多属性大量数据时,分类效果明显提高。 相似文献
67.
针对产品在装配过程中可靠性低,产品故障频发及故障源多样性的问题,引入信息熵理论,首次提出“可靠度熵”的概念,对影响装配过程可靠性的故障源进行定量分析。建立可靠度熵的综合评判矩阵,结合专家打分法对可靠度熵综合权重进行评价和排序,同时结合客观性强的粗糙集对故障源进行属性约简,提取出影响装配过程可靠性的关键故障源。采取预防及改进措施减少故障源的发生,从而保证装配过程可靠性。以数控磨床的砂轮架为例,验证了上述方法的可行性和正确性。 相似文献
68.
不完备形式背景中包含有不确定性信息,其上的知识表示与完备形式背景上的知识表示既有区别又有联系.为了研究两者的内在联系,定义了偏小近似形式背景与偏大近似形式背景,以及偏小近似概念格与偏大近似概念格,提出了偏大近似概念格上粗糙概念的识别方法,研究了偏小近似概念格与偏大近似概念格之间的蕴含关系.结论表明,可以用偏大近似概念格来作为不完备形式背景的知识表示工具. 相似文献
69.
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