共查询到20条相似文献,搜索用时 468 毫秒
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以磷矿为原料制备磷酸,通过化学沉淀法脱氟除杂质得到净化的磷酸,再将净化后的磷酸与碳酸钙反应制备饲料级磷酸二氢钙.考察了硫酸质量分数、石灰乳用量、反应时间和反应温度4个因素对磷酸二氢钙产率的影响,得到了制备磷酸二氢钙的最佳工艺条件:硫酸质量分数60%,石灰乳用量7.00 g,反应时间1.5h,反应温度50℃.在此最佳工艺... 相似文献
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甲醇沉淀法净化湿法稀磷酸制磷酸氢二铵 总被引:3,自引:1,他引:2
介绍了甲醇沉淀法净化杂质含量较高的湿法稀磷酸(五氧化二磷质量分数25.71%)制备高品质磷酸氢二铵(DAP)的方法.详细研究了碳酸氢铵用量、甲醇用量、反应温度及反应时间对湿法稀磷酸中杂质去除率和五氧化二磷损失率的影响.得到了优化的工艺条件:碳酸氢铵用量,即氮、磷物质的量比为0.25~0.50;甲醇用量,即甲醇与磷酸质量比为4;反应温度65℃,反应时间1.25~1.50 h.用净化后的湿法稀磷酸制备出了18-46-0规格的DAP.新方法为利用中低品位磷矿制备高品质肥料磷酸氢二铵提供了一条可行的途径. 相似文献
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以铁粉为铁源,LiH2PO4和酒石酸分别作为锂源和络合剂,采用机械活化法制备磷酸亚铁锂正极材料,制备出的材料具有振实密度较高的特点,有利于提高材料的体积能量密度.同其它制备高振实密度磷酸亚铁锂的方法相比较,该方法无需预先将原料制备成高振实密度、球形的中间体,因此大大地简化了工艺,易于实现工业化.研究认为机械活化时间对材... 相似文献
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For nickel and cobalt recovery from spent NiMH batteries by electrowinning, the effect of different electrowinning parameters as boric acid concentration, temperature, current density, and pH were studied using different synthetic solutions. The optimized operational parameters were applied in an electrowinning test with a solution achieved by leaching the electrodes of NiMH batteries. The electrowinning tests were performed galvanostatically in a two‐compartment cell separated by an anionic membrane. A platinum/iridium‐coated titanium anode and a stainless‐steel cathode were used. A sodium sulfate solution served as anolyte. The results demonstrate the technical viability of nickel and cobalt recovery. The chemical composition of the obtained deposit presented high nickel and cobalt concentrations. 相似文献
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A.J. Chaudhary J.D. Donaldson S.M. Grimes N.G. Yasri 《Journal of Applied Electrochemistry》2000,30(4):439-445
Optimum conditions are determined for the removal of nickel from cobalt solutions by electrodialysis exploiting the greater stability of the EDTA complex with nickel. The Ni–(EDTA)2– complex and hydrated Co2+ ions are transferred from the feed solution to the electrodialysis anolyte and catholyte chambers, respectively. A three compartment cell is required to prevent the transfer of hydrated Ni2+ from the anolyte chamber as the EDTA present is destroyed at the anode. Complete removal of nickel from cobalt can be achieved but there is a compromise between cobalt purity and the percentage of cobalt transferred to the catholyte chamber for recovery. 相似文献
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S. M. S. I. Dulal Chee Burm Shin Joon Yong Sung Chang-Koo Kim 《Journal of Applied Electrochemistry》2008,38(1):83-91
CoWP films were electrodeposited on copper-coated silicon wafers from citrate electrolyte containing cobalt sulphate, sodium
tungstate and sodium hypophosphite at room temperature potentiostatically. The effects of electrolyte concentration on thickness,
composition and microstructure of the films were studied. It was observed that the deposition current density and thickness
increased with increasing cobalt and hypophosphite ion concentrations, whereas an increase in tungstate ion concentration
resulted in a decrease in current density and thickness. Films with larger variations of cobalt (from 64 to 83 at.%), tungsten
(from 0.5 to 24 at.%) and phosphorus (from 6 to 21 at.%) were electrodeposited by controlling the concentrations of the electrolytes.
X-ray diffraction studies suggested that films containing ∼20 at.% phosphorus were amorphous while films with lower phosphorus
content were crystalline. SEM and AFM examinations showed that the size of crystallites and surface roughness were mainly
dependent on the amount of phosphorus present in the films. 相似文献
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S.M.S.I. Dulal 《Electrochimica acta》2007,53(2):934-943
Polarisation behaviour and nucleation mechanism of induced co-deposition of cobalt, tungsten and phosphorus from citrate electrolytes containing cobalt sulphate, sodium tungstate and sodium hypophosphite on copper disc electrode at various electrolyte pH values were studied using cyclic voltammetry and chronoamperometry, respectively. It was found that the onset potentials for reduction and oxidation gradually shifted towards more cathodic direction with increase in pH. Co-deposition of cobalt, tungsten and phosphorus occurred under diffusion control and followed instantaneous type of nucleation mechanism. The highest current efficiency (>70%) was found when the CoWP films were deposited from neutral or slightly acidic solution. Larger variation of film composition, cobalt from 48 to 74 at.%, tungsten from 13 to 38 at.% and phosphorus from 8 to 33 at.%, could be made by changing the pH of the electrolyte between 3 and 8. The films deposited from very acidic solutions contained larger amounts of tungsten and phosphorus and were amorphous; while the films deposited from near neutral solutions were polycrystalline and contained hexagonal cobalt. The surfaces of the amorphous films were smoother than those of the polycrystalline films. Needle-like dendritic crystallites were obtained when the films were deposited from basic solution or at elevated temperature. 相似文献
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The influence of cobalt ions in the solution on the anodic oxidation of a commercial Pb–Ca–Sn alloy under conditions typical
of copper electrowinning was studied using cyclic voltammograms and potential decay transients. The cobalt ions changed the
structure, morphology and chemical composition of the surface film from a loose porous film to a thin dense film. This change
of surface film is the cause for the decreased rate of oxidation for the lead anode in the presence of cobalt ions. The steady
state potential of the alloy during anodic oxidation decreased with (i) increasing cobalt ion concentration, (ii) increasing
rotation speed, (iii) increasing temperature, (iv) decreasing acid concentration and (v) decreasing current density. The steady
state potentials were lower in the presence of cobalt ions. This decrease in the steady state potential may indicate that
oxygen evolution is more rapid on the more compact film formed in the presence of cobalt ions. Alternatively, an additional
pathway of oxidation may be provided by the cobalt ions. 相似文献
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