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101.
The leaching behavior of a copper flotation concentrate was investigated using ammonium persulfate (APS) in an autoclave systee. The decomposition products of APS, active oxygen, and acidic medium were used to extract metals from the concentrate. Leaching experiments were performed to compare the availability of APS as an oxidizing agent for leaching of the concentrate under atmospheric conditions and in an autoclave system. Leaching temperature and APS concentration were found to be important parameters in both leaching systems. Atmospheric leaching studies showed that the metal extractions increased with the increase in APS concentration and temperature (up to 333 K). A similar tendency was determined in the autoclave studies up to 423 K. It was also determined that the metal extractions decreased at temperatures above 423 K due to the passivation of the particle surface by molten elemental sulfur. The results showed that higher copper extractions could be achieved using an autoclave system. 相似文献
102.
The kinetics of leaching arsenic from Ni-Mo ore roasting dust was investigated. The effects including leaching temperature, particle size of the smelter dust, stirring speed, the coefficient β(the molar ratio of sodium chlorate to arsenic in the smelter dust) and the initial H+ concentration on leaching arsenic were studied. The results indicate that the leaching of arsenic increases sharply with the decrease of particle size. The orders of reaction with respect to H+ concentration and particle size are determinted to be 1.136 and 1.806, respectively. The leaching of arsenic reaches 99% under experimental conditions, the apparent activation energy is determined to be 11.157 kJ/mol, which is consistent with the values of activation energy for diffusion model The kinetics equation of leaching arsenic from the roasting dust could be expressed by a semi-empirical equation as 1-2/3η (1 -η)^2/3 = k0(c[H+])^1.136ro^-1.806 exp[(-11157 /RT)t]. 相似文献
103.
This work investigates the stabilizing impact of MnO on the leaching behavior of hazardous Cr-containing CaO-SiO2-Al2O3-Cr2O3-MnO stainless steel slags after equilibrating at various elevated temperatures and evaluates the potential immobilization of Cr into a MnCr2O4 spinel phase from the existing Cr2O3 phase. The MnCr2O4 spinel phase was found to be an excellent Cr-stabilizer in stainless steel slags, where the leaching tendency of potentially hazardous Cr-related ions decreased with higher MnO content and lower equilibration temperatures within the range of 0 to 15 mass pct. and 1500 to 1300°C, respectively. Thermodynamic calculations by conducting the phase stability diagram also showed that the MnCr2O4 spinel phase was relatively stable and the Ca3Si2O7 (Ca3-xMnxSi2O7) phase was relatively unstable compared with other crystal phases in acid extractant with pH value of 3.2. Combined with the scanning electron microscopy and X-ray powder diffraction results along with the thermodynamic calculations, the leached Cr-related ions was predominantly originating from the unstable amorphous glass phase. 相似文献
104.
Valentin G. Greb Martin Bertau Axel Düker Andreas Geisbauer Peter Fröhlich 《化学,工程师,技术》2021,93(11):1827-1832
Petrochemical catalysts are widely used in the industry. For the production of cumene, zeolite-based catalysts containing phosphoric acid are applied. Over the time, coking deactivates the surface, and the catalyst has to be exchanged and disposed of. Different process approaches for recycling the phosphoric acid-containing catalysts were investigated. Related preliminary investigations have shown that calcination of the used catalyst is necessary prior to reprocessing. By digesting the catalyst with hydrofluoric acid, ∼96 % phosphate was recovered. However, this process is very costly in terms of process technology. More promising is digestion by basic or acidic routes. Several options are possible here, and digestion with H3PO4 proved to be particularly suitable. Here, phosphate yields reached up to 98.8 %, with a positive balance of economic efficiency at the same time. The catalyst can be produced and recycled in the same plant with the same reagents, what constitutes a major breakthrough towards sustainability in industrial catalysis. 相似文献
105.
106.
The heap leaching of oxide copper ores with copper cathode recovery by solvent extraction and electrowinning is now well established as a low-cost method of copper recovery. This technology has recently been applied successfully to mixed oxide and chalcocite ores, notably in Chile at Cerro Colorado, Quebrada Blanca and Zaldivar.Currently, there are significant development efforts underway to try to extend heap leaching to chalcopyrite ores.The success of heap leaching/SX/EW has also led to a revival in the development of hydrometallurgical processes to recover copper from chalcopyrite and other copper concentrates. The current status of copper hydrometallurgy is reviewed and the most commercially attractive potential applications are explored. The advantages and disadvantages of the hydrometallurgical treatment of chalcopyrite concentrates and its preliminary economics are compared with those for the current best practices in copper smelting and refining. 相似文献
107.
加压碱浸处理氰化浸出法回收汽车废催化剂中的贵金属 总被引:7,自引:0,他引:7
为提高铂族金属的浸出回收率,针对前期研究提出的汽车废催化剂先经加压碱浸处理而后再加压氰化浸出铂族金属的新工艺,变动预处理反应过程各种工艺参数,考察了对后续铂族金属氰化浸出指标的影响。结果表明:预处理可打开汽车废催化剂载体对铂族金属的包裹,有利于其氰化浸出;但物料粒度过细或反应碱用量过大、温度过高、时间过长均容易形成新相重新包裹,不利于氰化试剂与铂族金属有效接触;预处理渣进一步湿磨,可消除包裹,提高氰化浸出率;在实验最佳条件下,铂族金属氰化浸出率分别可达到:Pt 96%、Pd 98%、Rh92%。 相似文献
108.
REACTIONSOFPYRITEINCATALYTICALOXIDATIONACIDLEACHINGSYSTEM¥Xia,Guangxiang;Tu,Taozhi;Yang,Hanlin;Shi,Wei(InstituteofChemicalMet... 相似文献
109.
110.
微波作用下铝酸钙炉渣非等温浸出动力学 总被引:3,自引:5,他引:3
研究了微波作用下铝酸钙炉渣非等温浸出动力学,考察了不同微波辐射功率对炉渣中氧化铝浸出率的影响以及相应微波功率下反应体系温度随时间的变化规律。结果表明:该浸出动力学过程的控制步骤为界面化学反应控制,表观反应活化能为40kJ/mol左右;微波作用可改变反应的频率因子,对反应活化能影响不明显;随着微波辐射功率的增大,频率因子增加,宏观表现出微波功率的增加对反应有促进作用。 相似文献