Narrow Results

A method of modifying calcium carbonate particles was investigated by coating sodium stearate or sodium oleate on the surface of calcium carbonate by wet method. The results of FTIR, activation and dispersion index, dispersity in kerosene, surface wettability tests and zeta potential tests show that sodium stearate or sodium oleate has successfully coated on the surfaces of calcium carbonate. The main factors were researched and the optimal parameters were obtained for the best modification effect. Compared with common rubber, the modified calcium carbonate added rubber has larger breaking tensile strength (more than 21%) and larger elongation at break (more than 16%). This research provides a feasible way of modifying calcium carbonate for its use as filler in organic matrix, reduces the cost and has a potential application in large-scale production of modified calcium carbonate.

The interactive effect of siderite and hematite and its mechanism were investigated through flotation tests, dissolved components logarithm diagram, calculations of EDLVO theory and SEM. The results of flotation test show that the hematite recovery can be declined in some degree by adding various particle fractions of siderite, which the reason is that some collector will be consumed by various particle fractions of siderite, what's worse, the HCO₃^- and CO₃^2- dissolved from siderite can compete with oleate ions on the surface of hematite. In addition, the recovery of fine siderite can be improved by adding hematite. Calculations of EDLVO theory and SEM indicate that some part of the fine grade siderite cover on the surface of hematite after the addition of coarse hematite, as a result, the apparent grain size of fine siderite as well as the possibility of adhesion between fine siderite and bubble are incresed, what's more, the environment of flotation is optimized as well.