Search

The mineralogical characteristics of tantalum-niobium ores from Songzi were investigated using mineral liberation analyzer (MLA) and chemical analysis. In particular, the chemical composition, phase composition, particle size, and dissemination characteristics of the ores were studied in detail. Results show that TaO and NbO have grades of 0.013 % and 0.011 %, respectively. The main valuable minerals in the ores are tantalite, columbite, tantalum-niobite, and microlite, and the gangue minerals associated with tantalum-niobium minerals mainly include quartz, kaolinite, illite, feldspar, and mica among others. The minerals are embedded in a complex manner. Tantalum-niobium minerals with most particle sizes of −0.040 mm are disseminated in minerals, such as mica, illite, quartz, and partially intergrown with topaz and zircon, where they could not be easily liberated. Thus, the ores are classified as low-grade, micro-fine, and refractory tantalum-niobium ores. Based on this consideration, the process of classification-gravity concentration-magnetic separation-middlings regrinding and gravity concentration are finally determined and satisfactory indices are obtained. Two rough concentrates are produced: Concentrate I has TaO and NbO grades of 7.0292 % and 3.546 %, respectively, as well as recovery of 49.42 % and 35.46 %. By comparison, Concentrate II has TaO and NbO grades of 7.0292 % and 3.546 %, respectively, as well as recovery of 49.42 % and 35.46 %. [ABSTRACT FROM AUTHOR]

Flotation column is widely used as the separation equipment for fine mineral due to its high selectivity. However, this device may be unsuitable for the coarse particle flotation and has high handling ability. A two-stage flotation column with dimensions of 2 000 mm×1 000 mm×4 000 mm was designed to enhance the column flotation process. The energy input was modified by adjusting the flow rate and the head of circulating pump. The flotation column was designed with low energy input in the first stage (speed flotation stage) to recover easy-to-float materials quickly, and high energy input in the second stage (recovery stage) to recover difficult-to-float minerals compulsorily. Contrast experiments on the throughput and coarse coal recovery of high ash coal from the Kailuan Mine were conducted using conventional single-stage flotation column and the two-stage flotation column. The results show that the combustible matter recovery of the two-stage flotation column is 5.25% higher than that of the conventional single-stage flotation column. However, the ash contents of clean coal for both columns are similar. Less coarse coals with low ash are obtained using the two-stage flotation column than that using the single-stage column flotation with the same handling ability. The two-stage flotation column process can enhance coal flotation compared with the conventional single-stage column flotation. [ABSTRACT FROM AUTHOR]

Coal slimes are mainly composed of coal and clay particles. The interaction energies among these particles were calculated using extended DLVO (DERJAGUIN-LANDAU-VERWEY-OVERBEEK) theory and the aggregation mechanisms were analyzed based on the settling experiments for coal-kaolinite and coal-montmorillonite suspensions, respectively, under different conditions of water hardness. The results indicate that for coal-kaolinite suspensions, as the water hardness reaches 10.0 mol/L, the coal particles aggregate with each other easily, and then, the coal particles may aggregate with kaolinite particles. However, no aggregation occurs between kaolinite particles. A clay platelet network is formed in coal-montmorillonite suspensions by montmorillonite particles and coal particles are captured into the network. Coal and montmorillonite particles settle completely. [ABSTRACT FROM AUTHOR]

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 (NaSiO) 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. [ABSTRACT FROM AUTHOR]