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Combined with the characteristics of flotation feed originating from China's Panyidong Coal Preparation Plant, the ash, zeta potential, X-ray fluorescence spectroscopy and contact angle test were used to study changes in the surface properties of flotation feed under ultrasonic pre-treatment, and its effect on flotation of coal slime. Results show that Preferred pre-treatment process is ultrasonic secondary treatment, ultrasonic secondary pre-treatment can remove most of the high-ash fine mud for instance kaolinite, montmorillonite and quartz in the coal slurry, reduce the surface electronegativity of coal particles, and increase the contact angle of coal particles. Thus, the concentrate ash content decreases to 13%, the recovery rate, yield of flotation concentrate and combustible matter recovery reach 92.6%, 90.9% and 97.6%, respectively. [ABSTRACT FROM AUTHOR]

The article presents abstracts of several studies on environmental geochemistry. Some of the abstracts presented include "Biogeochemical Cycling of Nutrients in Karstic Catchments, Southwestern China: Linkages to Changes of Eco-Environments," by Congqiang Liu and "Emerging Organic Contamination in China," by Guibin Jiang and colleagues.

Two polysaccharides (ULP1 and ULP2) were isolated through ultrasonic-assisted extraction from green seaweed Ulva lactuca L. which was collected from the South China Sea. The highest yield of 17.57% was obtained under the conditions of 2% NaOH, 90 °C, material/water mass ratio 1:80, liquid extraction 5h and subsequent ultrasound-assisted extraction 1h. The structure of ULPs were characterized with periodate oxidation followed by Smith degradation, (1)H NMR, (13)C NMR spectroscopy, FTIR, and GPC. The molecular weights of ULP1 and ULP2 were 189 kDa and 230 kDa, respectively. The structural characteristics of ULP1 and ULP2 were quite similar. They were composed of rhamnose, xylose, glucose, and glucuronic acid. The content of rhamnose, xylose, glucose, glucuronic acid, sulfate was 51.2%, 12.3%, 20.1%, 16.4%, 12.0% for ULP1, respectively, and 60.8%, 14.2%, 8.2%, 16.8%, 26.8%, respectively, for ULP2. Both ULP1 and ULP2 showed good surface activity. 5 mg/mL ULP1 (2.62×10(-2) mmol/L) decreased the water surface tension to 51.63 mN/m. The critical micellar concentration of ULP1 and ULP2 was 1.01 mg/mL (5.3×10(-3) mmol/L) and 1.14 mg/mL (5.0×10(-3) mmol/L), respectively., (Copyright © 2015 Elsevier B.V. All rights reserved.)