Advanced Materials Research Vols. 634-638

Abstract: Water in Lower Aquifer of Quaternary is one of the mine water inrush sources during working faces being mining in the Northern Section of 8 Coal Seam in West No.1 Mining Area. Water flowing fractured zone, F1 fault, F22-a fault and F48 fault are main water-conducting channels in mining. According to the analysis of geology and hydrographical geology of the mine area, and combined with “Water Prevention Regulation of Coal Mines” and “Regulations of pillar leaving and coal mining under building, water, railway and mail shaft and tunnel”, stope layout was optimized, i.e. the minimum waterproof coal(rock) pillar between working face and Lower Aquifer Quaternary is 70 meter, the waterproof coal(rock) pillar between working face and F1 fault, F22-a fault, F48 fault is 70~95 meter, 70~75 meter, 80~90 meter respectively. Each shallow waterproof coal (rock) pillar of fault is narrow at the top and tends to increasingly widen at the bottom.

Abstract: Phosphate being one of the three major nutrients required for agricultural plant growth usually presents as collophane in China. Since fine phosphate and other gauge minerals associate with each other and form intergrowth, the beneficiation of collophane is extremely difficult. In this paper, the flotation strategy for a low grade collophane ore from Guizhou province in China was studied in detail. Direct, reverse and direct-reverse combined flotation sheets were employed to collophane flotation. The results reveal that direct-reverse flotation is a suitable flotation flow sheet for this collophane ore. With direct-reverse flotation sheet, the grade of P2O5 in concentrate is 33%, which is improved by 3% comparing direct flotation and P2O5 recovery could achieve 80%. In addition, content of MgO decreased to 0.9%, which satisfied the requirement of wet-process phosphoric acid.

Abstract: A Mo middling has been obtained through Cu-Mo bulk flotation. In order to further enrich molybdenite and separate pyrite form this middling. A series flotation tests were conducted to concentrate Mo. Important parameters including regrinding fineness, CaO dosage and cleaning flotation stages were optimized to enhance Mo enrichment. In addition, a close-circuit flotation test was conducted under optimum parameters and a Mo concentrate with 22.92% of Mo grade and 93.75% of Mo recovery was obtained, which satisfied the plant requirement.

Abstract: A technology route of “Reverse flotation of acid-consuming gangue minerals–Acid leaching for copper–Extracting–Electrodepositing” is proposed for recovery copper from tailings with high content of calcium oxide and high content of combined copper oxide. The effect of the main factors involving regulator dosage, collector type and dosage was investigated. On this regard, a open-circuit flotation test scheme was proceeded, by which a concentrate was obtained with 3.84% of CaO grade, 71.57% of CaO recovery, 0.82% of Cu grade and 79.76% of Cu recovery. This concentrate can be directly used for the production of sulfuric acid leaching and preparation of electrolytic copper. This technology can be used to fully utilize Cu from tailings, which will help to extend raw material sourcing for Chinese Cu industry.

Abstract: In this study, the niobium enrichment research of the iron concentrate containing niobium was studied by coal-based direct reduction roasting followed by magnetic separation process. The distribution of niobium element and existence form of mineral bearing-Nb in roasted products were investigated under different roasting temperature which was ranging from 1100°C to 1300°C. X-ray diffraction analysis (XRD) was used to identify the various minerals and compositions of the roasted products. The microstructures of these products were analyzed by the scanning electron microscope (SEM), while the elemental analysis was carried out by using energy dispersive spectrometer (EDS) technique. The results of XRD and EDS analysis showed that most of the niobium minerals were Nb-Fe rutile and ulvospinel which scattered in slag, and only a little was adhered to the surface of metallic iron at 1100°C. And the niobium oxides were partly reduced to Ti-aeschynite and niobocarbide which attached on the surface of metallic iron, and most were still ulvospinel scattering in the slag at 1200°C. The Ti-aeschynite was gradually reduced to Nb adhering to the metallic iron particle forming Nb-Fe soild solution at 1300°C.

Abstract: The environmental pollution is one of the most challenging fields that people has to be faced with. A series of environmental pollution caused by coal mining are closely related to the sustainable development of coal industry and society. Mining environment includes water environment, surrounding rock environment, stress environment, thermal environment, active faults, etc. In this paper, the environmental issues caused by mining and current research results were analyzed and summarized and several research direction of mining environment were put forward according to our national conditions and the consistent development of the coal industry.

Abstract: In order to study the strata behavior characteristics in super-long and large mining height working face, the FLAC-3D software was used to study the roof displacement and the abutment pressure distribution laws of working faces. The results indicate that: ① the influence range is larger of front abutment pressure in Liuzhuang coal mine 171301 super-long large mining height working face, and reaches to 60m. ② the maximum roof displacement increases with the increase of mining depth and working face length, the increase in magnitude decreases gradually, while the maximum roof displacement sharply increases due to the increase of mining height. ③ the peak abutment pressure increases with the increase of mining depth and mining height, the location of peak abutment pressure transfer to ahead of the coal wall. ④ the effect of working face length on abutment pressure is very feeble, so, the strata behavior characteristics remain almost constant with the increase of face length.

Abstract: Oolitic hematite is considered to be one of the most refractory ores in the world due to its ultra fine disseminated grain size and complex mineral composition. Various magnetic separation methods were conducted on the oolitic hematite ore samples from Guizhou Province. Because the TFe grades of each size fraction of the grinding products were different from each other, the beneficiation process of “classification – low intensity magnetic separation – high intensity magnetic separation” was finally adopted to guarantee the quality of iron concentrates. After the determined magnetic separation, the relatively good technical indexes are obtained. The TFe grade of iron concentrates is increased from 38.7% to 46.1%, and the iron recovery is 81.7%.

Abstract: High intensity magnetic separation tests have been carried out on the oolitic limonite ore with complex relations between limonite and gangue minerals of Honghe prefecture, and a optimal flowsheet for recover limonite from run-of-mine was adopted at last. High intensity magnetic separation flowsheet with one stage rougher, cleaner and scavenger, which have been studied respectively. Iron concentrate containing 55.18%Fe could be obtained at yield of 53.20% and recovery of Fe 68.45 % in closed circuit test.

Abstract: Against the dwindling status of mineral resources at present, effective recycling of tailings resources is an effective way to alleviate the shortage of resources, and to improve enterprise efficiency. This study was aimed to recover iron from tailings of Yangla copper ore, Fe content of which was 15.31%, and the content of strong magnetic iron mineral was about 11%. Considering low content of weak magnetic iron mineral and its complex and costly recovery process, weak magnetic iron mineral did not be recovered, so strong magnetic iron mineral was only recovered in this study. Under no grinding condition, Fe recovery of 6.47% with iron grade of 60.87% was obtained. It effectively recovered strong magnetic minerals from tailings, and got enterprise increase additional revenue with good economic benefits.