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The magnetism of pentlandite surface was enhanced through the selective precipitation of micro-fine magnetite fractions on pentlandite surfaces. This was achieved through adjustment of slurry pH and addition of surfactants. The results showed that at pH 8.8 with the addition of 100 g/t sodium hexametaphosphate, 4.5 L/t oleic acid, and 4.5 L/t kerosene, significant amount of fine magnetite particles adhered to the pentlandite surface, while trace amount of coating was found on serpentine surfaces. Thus, the magnetism of pentlandite was enhanced and pentlandite was well separated from serpentine by magnetic separation under the magnetic field intensity of 200 kA/m. Scanning electron microscopy (SEM) and zeta potential measurement were performed to characterize changes of mineral surface properties. Calculations of the extended Derjaguin–Landau–Verwey–Ocerbeek (EDLVO) theory indicated that, in the presence of surfactants the total interaction energy between magnetite and pentlandite became stronger than that between magnetite and serpentine. This enabled the selective adhesion of magnetite particles to pentlandite surfaces, thereby enhancing its magnetism.

As for the pulp-mixing process of small mineral, its flow field configuration principle is to obtain effective cycle in the same operating condition, and allocate strong shearing action according to the needs. This paper takes the coupling of secondary circulating flow pattern as the basis of flow field design to construct the double-impeller function system with the common effects of axial flow impeller and radial flow impeller, thus forming the high-efficient functional mechanism merging strong cycle and strong shearing together. It shows in the result that the effect of double-impeller configuration is strengthened compared to the conventional single-impeller pulp-mixing process: the decrease range of mixing time can reach about 50%; shearing mechanism has effectively blended in the related flow field, and achieved improvement on this basis. It means that the double-impeller configuration has respectively made up the shortage of the cycle performance in the single-impeller radial flow field and the shearing performance in the single-impeller axial flow field, initially formed the mixing mechanism characterized by high-efficient strong cycle mixing and high shearing mixing, and provided practical foundation to develop new and high-efficient modified pulp-mixing equipment.

The paper was to optimize the conditions of thermal and pressing dewatering of lignite based on four factors three levels of Orthogonal experiment and to study the effect of conditions on lignite burning characteristic. The results show that the importance to the dehydration rate of lignite is in turns, temperature, pressing time, pressure, particle size; and the optimizing condition is temperature 220℃, pressure 6MPa, pressing time 40min, and the particle size ratio 3 to 7. Thermo gravimetric analysis had been carried out to study the burning characteristic of the dewatered lignite. The results show that the burning characteristic temperatures: Preliminary release of volatile temperature, ignition point, point of maximum weightlessness rate, burnout temperature, are found to be an obvious rise, but the burnout temperature; and the four burning characteristic temperatures will be elevatory with the temperature elevated, pressing time extended and pressure increased.

Based on the analysis of the properties of oily sludge samples, the effect of modification parameters, such as liquid to solid (L/S) ratio, agitation temperature, agitation intensity, agitation time and pH on the modification of oily sludge was investigated with the content of oil remnants in dry sludge as a reference index. Remixing experiments were carried out according to a simplex-lattice design, where Sx4056 was used as the demulsifier, petroleum sulfonate as the surfactant and sodium silicate (Na2SiO3) as the dispersant. The surface modification reagent formulation was optimized by a regression equation on the modified effect and based on the amounts of surface modification reagents. The results show that the content of the oil remaining in dry oily sludge is 0.28% of 10.15% oily sludge, when the reagent concentration rises to 3.5 g/L under the optimum experimental conditions.

Aim at high-to-float high-ash fine coal with large content of granules, in order to reduce pollution of carried fine slime to quality of concentrate coal, soluble glass, sodium hexametaphosphate and cornstarch these three kinds of regulators were choosen to carry out flotation reducing ash experiment. Result showed that, cause of poor selectivity of fine coal is mainly small quality, big surface area and the poor dispersion of fine coal. When sodium hexametaphosphate dosage is 1500g/t, the kerosene dosage is 370g/t, the foam beater GF dosage is 150g/t, production rate of concentrate coal is 57.69%，and ash content of concentrate coal is 12.04%. Under the same condition, separation index of sodium hexametaphosphate as regulator is superior to cornstarch and soluble glass.

As for certain high ash and difficult floatable fine coal, the coal quality characteristic is the frangible and easyly-clayed main gangue mineral kaolinite, and the high content of fine-grade and intermediate density grade materials. In order to reduce tiny slimes pollution and to increase quality and recovery rate of concentrate, we used cyclonic-static micro-bubble flotation column and XFD-3 flotation machine to experiment on separation process. It probed into re-concentration after grinding rough refined coal, classified flotation process and selective agglomeration-flotation process these three technical processes. The comparison of flotation machine test result showed that, using the flotation column as separation equipment, process of re-concentration after grinding rough refined coal could obtain the best refined coal accumulation index. When medicaments dosage is kerosene 800 g/t, GF 300 g/t, and sodium hexametaphosphate 1500g/t, refined coal production rate of flotation column is 59.47% and ash content is 10.63%.

As certain refractory molybdenum with degree high oxidation and high argillization, on the premise of molybdenum concntrate recovery rate, in order to increase tenor of molybdenum concntrate, we use cyclonic static micro-bubble flotation column as concentration equipment. We used two concentrate courses to replace flotation machine eight concentrate courses. It showed that, in the condition of same recovery rate, tenor of molybdenum concntrate was 26.16%, rising by 8%. Using processes of flotation machine eight concentrate courses - concentrate regrinding - flotation column two concentrate courses, tenor of molybdenum concntrate was 39.33% and the recovery rate was of 8%. The results showed that, by increasing the degree of monomer dissociation of molybdenum ores, cyclonic static micro-bubble flotation column has higher capability in recovering and selecting ores of -400 mm size fraction. The high argillization resulting from the regrinding and unsuppressed gangue minerals are the main factors affecting the tenor of ore concentrate.