Removal of Ash Contents from Coal by Flotation.

Research Project

Project/Area Number	60850114
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	資源開発工学
Research Institution	TOHOKU UNIVERSITY
Principal Investigator	MATSUOKA Isao Tohoku University, Faculty of Engineering, Assoc. Prof., 工学部, 助教授 (80005264)
Co-Investigator(Kenkyū-buntansha)	TAKEDA Susumu Tohoku University, Faculty of Engineering, Research Assoc., 工学部, 助手 (40124599) SUZUKI Teruo Tohoku University, Faculty of Engineering, Assoc. Prof., 工学部, 助教授 (50004297)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥4,500,000 (Direct Cost: ¥4,500,000) Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000) Fiscal Year 1985: ¥2,900,000 (Direct Cost: ¥2,900,000)
Keywords	Removal ash contents / Flotation / Coal / 分散
Research Abstract	The removal of ash contents from coal has been investigated by a flotation method which differs from a conventional flotation method in that ash contents are floated and coal is remained in the suspension. The results obtained are as follows : Clay minerals such as kaolinite, dickite, pyrophillite and sericite which are main constituents of ash contents of coal could be effectively floated by sodium oleate as a collector at pH above 11.5 after calcium activation. Pressure flotation experiments using kerosine as a collector showed that ash content of Dah Torng coal from China was more significantly decreased than those of Horonai, Taiheiyo and Goonyella coals. From this result, Dah Torng coal was chosen as a sample of this investigation. Flotation experiments of Dah Torng coal using sodium oleate as a collector and calcium chloride as an activator showed that ash content of sink(coal concentrate) decreased at pH about 11.5, but 40-60 % of coal was floated. Then, various reagents were tested in order to depress flotation of coal. Starch depressed ash contents as well as coal. Polyoxyethyleneoctylphenylether (HS-210, manufactured by Nippon Oil & Fats Co.,) had a slight effect on coal depression. Polyvinyl alcohol showed the most selective depressing action for coal among reagents tested in this investigation. But, satisfactory result could not be obtained, i.e., ash content of coal concentrate(sink) was about 5 % and coal recovery was about 80 %.