The main objective of the current work is to recover SiO2 various acid concentrations,scrubbing time,and attrition impeller speed for crystal glass application.Silica rocks were treated using a physico-chemical method...The main objective of the current work is to recover SiO2 various acid concentrations,scrubbing time,and attrition impeller speed for crystal glass application.Silica rocks were treated using a physico-chemical method involving physical separation method using citric and sulphuric acids as the reagents.Low acid concentration range of 1%-2%and variable scrubbing time of 10,20,and 30 min were investigated.The microstructure,phase,and particle size of the silica rocks were determined after scrubbing process.Citric acid was found effective in improving the purity of SiO2 to 99.8%at 0.75%concentration,via a 20 min scrubbing process operated at 1,250 rpm(rotations per minute).The phase structure and morphology of the recovered SiO2 were confirmed as trigonal crystal structure with small and irregular shape.To date,studies on the processing of silica rock using organic acid are yet very limited.展开更多
Selective separation of silica from a siliceous-calcareous phosphate ore that had been sieved into different size fractions is investigated by a combination of chemical analysis,zeta potential measurement and FTIR and...Selective separation of silica from a siliceous-calcareous phosphate ore that had been sieved into different size fractions is investigated by a combination of chemical analysis,zeta potential measurement and FTIR and XPS techniques.Scrubbing is a better choice than flotation for removing silica from the coarse fractions.The P_2O_5 grade of the coarse fractions is increased to about 30%by scrubbing and the product yields are higher than those obtained by flotation.The silica in the fine fraction is separated by reverse flotation.An alkyl amine salt(DAH)is an effective collector and the P_2O_5 grade of the fine fraction can be increased by 7%to beyond 30%under acidic conditions.The higher zeta potential obtained using DAH suggests that it is more strongly absorbed onto the ore particles than the other cationic collectors. FTIR and XPS results confirm physical absorption of the cationic collector onto the ore surface.They also indicate that calcite is dissolved at low pH values,which increases the Si concentration on the ore surface.展开更多
文摘The main objective of the current work is to recover SiO2 various acid concentrations,scrubbing time,and attrition impeller speed for crystal glass application.Silica rocks were treated using a physico-chemical method involving physical separation method using citric and sulphuric acids as the reagents.Low acid concentration range of 1%-2%and variable scrubbing time of 10,20,and 30 min were investigated.The microstructure,phase,and particle size of the silica rocks were determined after scrubbing process.Citric acid was found effective in improving the purity of SiO2 to 99.8%at 0.75%concentration,via a 20 min scrubbing process operated at 1,250 rpm(rotations per minute).The phase structure and morphology of the recovered SiO2 were confirmed as trigonal crystal structure with small and irregular shape.To date,studies on the processing of silica rock using organic acid are yet very limited.
基金the National Key Technology R&D Program of China forthe support of this work(No.2007BAE58B01).
文摘Selective separation of silica from a siliceous-calcareous phosphate ore that had been sieved into different size fractions is investigated by a combination of chemical analysis,zeta potential measurement and FTIR and XPS techniques.Scrubbing is a better choice than flotation for removing silica from the coarse fractions.The P_2O_5 grade of the coarse fractions is increased to about 30%by scrubbing and the product yields are higher than those obtained by flotation.The silica in the fine fraction is separated by reverse flotation.An alkyl amine salt(DAH)is an effective collector and the P_2O_5 grade of the fine fraction can be increased by 7%to beyond 30%under acidic conditions.The higher zeta potential obtained using DAH suggests that it is more strongly absorbed onto the ore particles than the other cationic collectors. FTIR and XPS results confirm physical absorption of the cationic collector onto the ore surface.They also indicate that calcite is dissolved at low pH values,which increases the Si concentration on the ore surface.
