%0 Journal Article %A DENG Rong-Dong %A LI Shi-Qi %A XING Ding-Quan %A ZHAO Rui-Qi %A ZHOU Jiang-Hui %T Floating and sinking experiment and mechanism of calcite coating?acid reaction %D 2022 %R 10.12034/j.issn.1009-606X.221225 %J The Chinese Journal of Process Engineering %P 1094-1102 %V 22 %N 8 %X Calcite, as a major gangue mineral, is often found in other calcium-bearing minerals. Froth flotation is the main method to separate calcite from other calcium minerals. However, due to the similar physicochemical characteristics of calcium-containing minerals, it is difficult to separate these minerals effectively by the conventional flotation method. Different from non-carbonate minerals, calcite has the characteristics of reacting with an acid to generate CO2 bubbles. These CO2 bubbles can effectively reduce the apparent specific gravity of calcite in a short time. Polyvinyl alcohol film has selective permeability, which can allow H+ to pass through and as a barrier to CO2 bubbles. The high polymer film can bind the generated CO2 bubbles on the surface of calcite. When there are enough CO2 bubbles, the calcite particles will float spontaneously and be separated from the calcium-containing non-carbonate minerals. The coating effect directly affects the separation effect. Therefore, it is necessary to determine conditions of appropriate coating and acid reaction to improve the effectiveness of calcite coating-acid reaction. In this work, the main factors that affect the calcite coating-acid method were systematically studied through single factor experiments and orthogonal experiments. The optimum conditions of sulfuric acid concentration, PVA type and concentration, methyl isobutyl carbinol (MIBC), and sodium dodecyl sulfonate (SDS) concentration were screened by a single factor test. The orthogonal test was carried out for three factors, acid concentration, PVA concentration, and MIBC concentration. The results showed that the coating-acid reaction method can realize the self-floating of calcite particles (1 mm). The optimum conditions of the calcite coating-acid reaction method were sulfuric acid concentration of 2.0wt%, PVA type of P139546, PVA concentration of 2.4wt%, and 40 mg/L MIBC which was conducive to the floating of calcite. Under these conditions, the floating rate of calcite was 84.9%, and the average floating time was 28.8 s. The combination of SDS and PVA can effectively improve the floating time of calcite, while the floating rate was lower than that without SDS. PVA concentration and acid concentration were the main factors affecting the calcite coating-acid reaction method. %U https://www.jproeng.com/EN/10.12034/j.issn.1009-606X.221225