No abstract

Flotation is the most known beneficiation method for the separation of complex and refractory iron ores. As a typical iron-containing silicates, it is difficult to separate chlorite from specularite, because of the similar surface physicochemical properties. In this study, the selective depression effect of sodium hexametaphosphate (SHMP) was conducted via the cationic micro-flotation. The surface adsorption mechanism between SHMP and the two mineral surface was explored through surface adsorption amount tests, Zeta-potential measurements, Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses. The micro-flotation results indicated that SHMP could selectively depress around 90% of chlorite, while its effect on the floatability of specularite was negligible (<20% depressing). The surface adsorption amount tests, Zeta-potential measurements analysis demonstrated that SHMP selectively adsorb on chlorite surface while on the surface of specularite is feeble. The further surface adsorption analysis via FT-IR and XPS proved that SHMP selective adsorption occurred on the chlorite surface mainly by chemisorption mainly through the chelation reaction between O in the phosphate groups of SHMP molecular and metal ions on surface of chlorite.

Cement is an important way to digest industrial waste. Semi-dry gas desulfurized ash (SGDA) and granulated blast furnace slag (GBFS) as solid waste both have pozzolanic activity as well as small particle size and continuous particle size distribution, which allow their use as cement mixtures. In the present work, a cement matrix with 60% Portland cement, 20% SGDA, and 20% GBFS, including 3% nano-TiO 2 and 2% nano-SiO 2 as dopants, was produced via cement slurry mixing process. The obtained matrix was found to have the better 3-and 28-day age compressive strength (by 104% and 116%, respectively) as compared with the pure Portland cement; the mortar compressive strength is