硫磷混酸浸出黑钨矿动力学

采用单因素实验法研究了硫磷混酸分解黑钨矿浸出过程中的动力学过程,考察搅拌速度、矿物粒度、反应温度、硫酸浓度和磷酸浓度对黑钨矿浸出速率的影响。结果表明:黑钨矿在该体系中的浸出过程可用Avrami方程描述,其模型特征参数为0.83,反应的表观活化能为67.54 kJ/mol,属化学反应控制,建立硫磷混酸浸出黑钨矿的反应动力学方程。     

KOH亚熔盐中钒渣的溶出行为

对钒渣在KOH亚熔盐体系中的分解动力学进行研究,考察反应温度、碱矿质量比、粒度、气流量等工艺参数对钒渣分解过程的影响,获得最优工艺参数,并对反应机理进行探讨。结果表明,反应温度是最重要的影响因素;钒渣最优浸出条件如下:在反应温度为180℃,碱矿比4:1,KOH碱浓度75%,搅拌速率700 r/min,反应时间300 min,常压通氧气流量为1 L/min的反应条件下,最终钒、铬的浸出率分别达到95%和90%以上。钒渣在KOH亚熔盐介质中氧化分解遵循缩核模型,并主要受内扩散控制,钒和铬分解的表观活化能分别为40.54和50.27 kJ/mol,钒铬尖晶石的氧化以铁橄榄石、石英相的氧化分解为前提。     

复杂高硅钴白合金碱焙烧脱硅预处理

针对高硅钴白合金结构复杂、难以直接硫酸浸出问题,开展碱焙烧脱硅预处理研究以破坏稳定致密的硅铁合金结构。结果表明:经碱焙烧预处理后,钴白合金形貌发生明显改变。碱焙烧条件如下:温度600℃,NaOH用量为硅、铁反应所需理论量0.64倍。在上述条件下焙烧2 h后,所得渣经水洗,硅的脱除率达到66.57%;再经常压硫酸浸出,钴、铁浸出率均高达99%以上,而铜则完全保留在浸出渣中,实现了钴和铜分离,渣中的铜经第二段氧化浸出得以回收。进一步基于工艺矿物学分析,对碱焙烧脱硅预处理后钴白合金的常压浸出行为进行解析。     

高砷烟尘NaOH-Na_2S碱浸过程的金属元素浸出行为（英文）

采用NaO H-Na_2S碱浸方法实现了高砷烟尘中砷的选择性浸出。在砷浸出过程中,探讨了碱料比、硫化钠用量、浸出温度、浸出时间和液固比对各金属元素浸出率的影响。结果表明:在碱料质量比为0.5,硫化钠用量为0.25 g/g,浸出温度为90°C,浸出时间为2 h,液固比为5:1的优化条件下实现了砷与其他金属的有效分离。在优化条件下,砷、锑、铅、锡和锌的平均浸出率为92.75%,11.68%,0.31%,29.75%和36.85%。NaOH-Na_2S碱性浸出过程提供了一种从含砷烟尘中脱除砷的简单有效的方法,同时产生具有利用价值的铅渣。     

硅酸钠分解白钨矿的热力学研究

针对硅酸钠分解白钨矿的问题,对Ca-Si-W-H2O体系进行了热力学平衡分析,获得了一系列平衡关系图。理论分析表明,白钨矿可被硅酸钠分解,随着pH值升高,分解固相产物依次为CaSiO3和Ca3Si2O7。在低pH值的CaSiO3稳定区,白钨矿被硅酸钠分解,但溶液中钨浓度较低;在高pH值的Ca3Si2O7稳定区,氢氧化钠也参与了分解反应,钨浓度随pH值上升迅速增加。因此,硅酸钠分解白钨矿时可添加适量的氢氧化钠,以提高钨矿分解效果。分解实验验证了理论分析结果,实际分解效果变化的趋势与热力学分析一致。硅酸钠用量是影响浸出总体水平的重要因素,提高试剂浓度或添加氢氧化钠,能进一步提高钨的浸出率。对于WO3质量分数为55.0%白钨矿,在分解温度为180℃,分解时间为4 h,体系中硅与钨、氢氧根与钨、水与钨的摩尔比分别为2.0、0.5、35.3的条件下,钨的浸出率为96.9%。     

葡萄糖在氧化锰矿浸出过程中的分解动力学

研究在硫酸水溶液体系葡萄糖还原浸出氧化锰矿过程中的分解动力学,通过测定溶液中COD含量的变化,考察葡萄糖用量、硫酸浓度、氧化锰矿用量和反应温度对葡萄糖氧化分解速率的影响。结果表明:提高硫酸浓度、氧化锰矿用量和反应温度可以加快浸出反应过程葡萄糖的氧化分解速率。葡萄糖的氧化分解过程可以用指数经验模型来描述,属于扩散-化学反应混合控制。通过拟合动力学数据,获得葡萄糖氧化分解反应的活化能为41.80 k J/mol,COD、硫酸和氧化锰矿的表观反应级数分别为2.0,0.927和0.976。     

铁矾渣热酸分解及硫脲提银

进行铁矾渣热硫酸分解和分解渣硫脲法提银的试验研究,考察硫酸用量、分解温度、反应时间、液固比对铁矾渣中Fe、Zn、Ag浸出率的影响,以及硫脲法提银的最优条件。结果表明:在硫酸用量为其理论值的1.5倍、分解温度95℃、时间2.5 h、液固比2.5:1的最佳条件下,铁矾渣中Fe和Zn浸出率分别为93.85%和92.25%,而Ag的浸出率仅为1.99%。分解液净化后可用中温水热法制备铁红,分解渣中Ag富集到1060 g/t。在液固比10:1、硫脲浓度15 g/L、浸出温度90℃、反应时间2.5 h的最优条件下,Ag的平均浸出率在93%以上,同时,渣中Pb的品位由1.7%提高到7.5%。     

难溶铑物料高温高压快速溶解技术研究

铑粉的溶解是铑精炼提纯中的重要环节。传统方法溶解周期长,转化率低,易引入污染,使用高压釜在高温高压下溶解铑粉具有较强的应用前景。研究了液固比、盐酸浓度、温度等因素对铑粉浸出的影响。得到的最佳浸出工艺条件为:液固比10:1,盐酸浓度5 mol/L,反应温度200℃,氧气分压0.5 MPa,氯酸钠氧化剂用量为铑粉量的4倍。在400 r/min搅拌转速下反应,经3 h铑粉的一次浸出率达到99%以上。     

碱浸浮选法处理铝电解废旧阴极的工艺研究

通过对废旧阴极内衬的分析,采用碱浸浮选法对其进行处理,回收其中的有用成分,将有害物质分解从而保护环境。碱浸过程中,通过对碱用量、温度、反应时间和液固比这些单因素的分析,确定了最佳反应条件。炭的纯度提高到83.61%,回收了Na3AlF6和NaF;浮选实验有效地分离了炭和电解质,最终炭的纯度达到95%,电解质纯度为98%;最后用漂白粉对实验废水进行处理,分解有害的氰化物并回收CaF2。     

粉煤灰提铝渣中二氧化硅在高浓度碱液中的溶解行为

粉煤灰酸法提取氧化铝后渣中二氧化硅含量接近85%,是制备硅酸钠水玻璃的优质原料.提出了在常压下用高浓度碱液浸出粉煤灰提铝渣中二氧化硅的工艺;研究了二氧化硅在浓碱体系中的浸出行为.实验结果表明,在温度为110 ℃、碱浓度为50%、液固比为2.2-1、时间为60 min条件下反应最佳,碱浸渣的XRD分析表明,对酸渣进行二次碱浸后,渣中SiO2浸出完全,主要物相为钠硅渣和碳酸盐.     

磷砷渣返回压煮处理的工艺研究

分析了在黑钨精矿碱压煮条件下 ,磷砷渣中钨和污染因子砷的行为。通过试验 ,摸索了磷砷渣返回压煮处理的工艺条件。在过碱系数 1.42 ,加入氧化剂等添加剂的情况下 ,适量的磷砷渣与精矿一起压煮 ,精矿分解率达 98.8% ,溶液质量满足后续工序要求 ,同时实现了有害磷砷渣向无害钨渣的转化。     

Sodium hydroxide digestion of scheelite by reactive extrusion

According to the thermodynamic analysis, scheelite can be decomposed as long as the NaOH concentration is high enough, even at low temperatures. As for the approaches of increasing NaOH concentration, it is more economical to reduce the water dosage at fixed NaOH dosage than to increase the NaOH dosage at a fixed ratio of liquid to solid. But the viscosity of slurry will be increased with the increase of the solid to liquid ratios, which will make the mass transfer more difficult if the conventional stirring equipment is still employed. Twin screw extruder is a kind of equipment which is suitable to work with highly viscous macromolecular materials. Good mass transfer can be easily obtained in this process. Therefore, it is considerable to apply this equipment to treat the highly viscous scheelite slurry. Based on these, a novel technology is proposed to digest scheelite with sodium hydroxide. Under the conditions of temperature 120 °C, screw rotating speed 160 rpm, reactive time 3.5 h and the NaOH dosage 2.2 times to stoichiometry, the content of WO₃ in the residue and the WO₃ extraction are 1.54% and 99.18%, respectively. The results indicate that scheelite can be decomposed with sodium hydroxide by reactive extrusion at a lower temperature.     

Sodium hydroxide digestion of scheelite by reactive extrusion

According to the thermodynamic analysis, scheelite can be decomposed as long as the NaOH concentration is high enough, even at low temperatures. As for the approaches of increasing NaOH concentration, it is more economical to reduce the water dosage at fixed NaOH dosage than to increase the NaOH dosage at a fixed ratio of liquid to solid. But the viscosity of slurry will be increased with the increase of the solid to liquid ratios, which will make the mass transfer more difficult if the conventional stirring equipment is still employed. Twin screw extruder is a kind of equipment which is suitable to work with highly viscous macromolecular materials. Good mass transfer can be easily obtained in this process. Therefore, it is considerable to apply this equipment to treat the highly viscous scheelite slurry. Based on these, a novel technology is proposed to digest scheelite with sodium hydroxide. Under the conditions of temperature 120 °C, screw rotating speed 160 rpm, reactive time 3.5 h and the NaOH dosage 2.2 times to stoichiometry, the content of WO₃ in the residue and the WO₃ extraction are 1.54% and 99.18%, respectively. The results indicate that scheelite can be decomposed with sodium hydroxide by reactive extrusion at a lower temperature.     

Wolframite Conversion in Treating a Mixed Wolframite–Scheelite Concentrate by Sulfuric Acid

Complete wolframite conversion in sulfuric acid is significant for expanding the applicability of the sulfuric acid method for producing ammonium paratungstate. In this paper, the conversion of wolframite in treating a mixed wolframite–scheelite concentrate by sulfuric acid was studied systematically. The results show that the conversion of wolframite in sulfuric acid is more difficult than that of scheelite, requiring rigorous reaction conditions. A solid H₂WO₄ layer forms on the surfaces of the wolframite particles and becomes denser with increasing H₂SO₄ concentration, thus hindering the conversion. Furthermore, the difficulty in wolframite conversion can be mainly attributed to the accumulation of Fe²⁺ (and/or Mn²⁺) in the H₂SO₄ solution, which can be solved by reducing Fe²⁺ (and/or Mn²⁺) concentration through oxidization and/or a two-stage process. Additionally, the solid converted product of the mixed wolframite–scheelite concentrate has an excellent leachability of tungsten in an aqueous ammonium carbonate solution at ambient temperature, with approximately 99% WO₃ recovery. This work presents a route for manufacturing ammonium paratungstate by treating the mixed concentrate in sulfuric acid followed by leaching in ammonium carbonate solution.     

Preparation of High－purity Sodium Tungstate from Low－grade Tung－sten－concentrate with a High Content of Calcium and Other Impurities

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A STATISTICAL INVESTIGATION OF FACTORS INFLUENCING FLOTATION OF WOLFRAMITE

本文尝试用统计分析的方法,综合研究了影响黑钨矿浮选的六个主要工艺因素:(1)粒度;(2)浮选气泡产生方式;(3)矿浆pH值;(4)起泡剂用量;(5)矿物是否预先经酸处理;(6)矿浆温度.按正交方阵进行了实验,对所得实验指标进行了方差计算并分析,结果表明,在用油酸钠浮选纯黑钨矿的场合,起显著作用的独立因素是矿物粒度、矿浆pH以及矿浆温度。文中详细分析了各项因素的交互作用,并找出了最佳的综合工艺条件。     

机床丝杠热膨胀零点及补偿技术研究

机床丝杠在运行时转速很高而且换向频繁,热量不能及时散出而产生很高的温升。丝杠为细长杆,对温度的变化敏感。根据丝杠热误差的产生规律,提出丝杠热膨胀零点的选取方法,建立误差补偿模型。研究机床丝杠热膨胀零点的补偿方法,分析丝杠热膨胀误差的补偿流程;通过补偿实验证明丝杠热膨胀零点对误差建模的意义。     

调整碱压煮工艺参数 提高复杂钨矿分解率

随着黑矿资源的枯竭,精矿中复杂矿的比率可增至10%以上,所谓复杂矿就是指按一般黑钨精矿碱压煮工艺分解,其分解率在(94～95)%的钨矿。通过调整工艺参数,要使疑难矿的分解率提高(4～5)%,具有明显的经济效益和社会效益。     

A new collector for wolframite slime flotation

With aniline and salicylaldehyde as main materials, a new collector for wolframite slime was synthesized. In a pulp of natural pH value, this collector can collect wolframite effectively. Its selectivity is similar to that of benzyl arsenic acid and better than that of sodium oleate. With this collector, a wolframite rough concentrate with grade 30.12 % WO3 and recovery 91.50 %, and a concentrate with grade 58.66 % WO3 and recovery 85.00 % were obtained respectively from a wolframite ore containing 4.08 % WO3.