Kinetic mechanism of copper extraction from methylchlorosilane slurry residue using hydrogen peroxide as oxidant

Copper was extracted from methylchlorosilane slurry residue by a direct hydrogen peroxide leaching method.A number of experimental parameters were analyzed to determine the extraction efficiency of copper.The extraction efficiency of copper reached 98.5%under the optimal leaching conditions,such as the hydrogen peroxide concentration of 1.875 mol·L^(-1),the leaching temperature of 323 K,the liquid–solid ratio of 20 ml·g^(-1),and the stirring speed of 300 r·min^(-1).The leaching kinetics of the copper extraction process was then described by the shrinking core model.There were two stages.The first stage was controlled by chemical reactions,while the second stage was controlled by interface transfer and product layer diffusion.The activation energy and kinetic control equations were determined,as well as an explanation of the leaching mechanism of copper extraction based on kinetic analysis and materials characterization.Copper resources can be recovered from the methylchlorosilane slurry residue efficiently and inexpensively with the methods used in this study.

Study on the Effect of Catalyst Properties on Residue Hydroconversion

The effect of catalyst properties on residue oil hydroconversion was studied at moderate operating conditions(at a temperature of 400 ℃, an initial hydrogen pressure of 10 MPa, and a reaction time of 4 h) in a batch mode slurry phase with different catalyst samples. The results showed that the catalyst acidity had a good effect on residue conversion and MCR(micro carbon residue) conversion but brought about higher coke yield. Residue conversion was thermally induced but the catalyst acidity changed its conversion route. A catalyst with higher metal loading, higher hydrogenation activity and appropriate pore size had higher sulfur and metal removal rate, higher MCR conversion and also a lower coke formation. The activity of spent commercial catalyst AS1 and DS1 was slightly lower than the corresponding fresh ones but was still high enough for residue oil hydroconversion. It assumes that the role of the catalyst is to activate hydrogen species toward reaction with an aromatic carbon radical to yield a cyclohexadienyl type intermediate which will turn into liquid and also to absorb the mesophase which can easily aggregate to form coke.

Measurement and analysis of biogas fertilizer use efficiency, nutrient distribution and influencing factors of biogas residues and slurry on pig farms

Although the effects of biogas residues and slurry returning to farmland are good,they still cannot be used widely in China.In this study,the biogas fertilizer use efficiency,nutrient distribution and influencing factors of fertilizer use efficiency of biogas residues and slurry in 20 biogas projects in Chongming County,Shanghai,China were measured and analyzed.The correlation and a linear regression fit of parts of test indicators were also analyzed.The results show that pig farm biogas residues and slurry mixture are nutrient-rich and can be used as a high-quality organic fertilizer,while its fertilizer use efficiency is unstable because of the differences among area,raw materials,fermentation technology and operation management.Nutrients are not evenly distributed in biogas residues and slurry.Higher levels of organic matters,P and trace elements were detected in biogas residues and higher levels of water-soluble N and K were detected in biogas slurry.The correlations between some test indicators of biogas residues and slurry mixture are significant,especially between total K and conductivity.Linear regression model fitting results of parts of test indicators are satisfactory.Hence,the values of the other test indicators can be estimated by one known indicator which can effectively reduce the determination workload under some limited situations.