Test materials

The magnesite ore used in the test was taken from the Haicheng Pailou mining area (Haicheng Magnesium Ore Refractory Material Plant). The overall colour of the ore is white, and the crystalline structure is dominant. The ore was crushed, screened and mixed in the laboratory to prepare a − 2 mm sample, a small amount of ore sample was taken for laboratory analysis, and the rest was stored for later use.

The single minerals magnesite, dolomite, and quartz were taken from the Haicheng Magnesium Mine Refractory Material Plant, Rongcheng Town Yuxi Ma Steel Dolomite Mine and Inner Mongolia Chifeng Quartz Mine, respectively. Relatively pure lump ore was selected and put through a series of processes such as manual selection, crushing, screening, and grinding. A − 0.106 mm + 0.044 mm particle size was finally obtained for use. Quartz must be soaked in dilute hydrochloric acid and repeatedly washed with distilled water to stabilize the pH value of the solution at approximately 7, and is ready for later use after drying.

The chemical element analyses of magnesite ore, magnesite, dolomite, and quartz single minerals are shown in Table ​Table1,1, and the X-ray diffraction test results are shown in Fig. 1.

Chemical composition of magnesite ore, and single mineral magnesite, dolomite, and quartz (wt%).

XRD pattern of sample.

Table ​Table11 and Fig. 1 show that the MgO content in the magnesite ore is 46.01%, the MgO content is 92.95% (IL = 0), and the impurity SiO₂ content is relatively high, followed by CaO and Fe₂O₃. The pure mineral sample of magnesite contains fewer impurities, in which the MgO content is 47.35%, the MgO content is 98.03% (IL = 0), and the MgCO₃ content is over 97%. The main component of dolomite minerals is dolomite, and the contents of elemental impurities such as iron, silicon and aluminium are relatively small. The main component of pure quartz minerals is SiO₂, with a content of 99.4%. Three kinds of minerals meet the requirements of the pure mineral flotation test.

The reagents used in the flotation test are ether amine, sodium silicate (Na₂SiO₃·mH₂O), and #2 oil (C₁₀H₁₇O), which are industrial products taken from the manufacturer. Sodium hexametaphosphate, trisodium phosphate, tannic acid and ammonium oxalate are chemically pure or analytically pure and purchased from a reagent sales company.

The ether amine was acidified with hydrochloric acid, and the ether amine hydrochloride solution was used as the flotation collector. The molar ratio of ether amine to hydrochloric acid is 1/1.1, and the amount of acidified ether amine (EAH) collector is based on the amount of ether amine.