Advanced Materials Research Vols. 734-737

Abstract: Based on the particularity of loose and broken of the surrounding rock of roadway, there will be rib spalling after excavating of roadway without support problem. Through analyzing for the specific reasons of the rib spalling, the theory of forepoling pre-stressed system and forepoling support project were put forward. The broken rock zone test in normal roadway support indicating that this technology can effectively prevent the rib spalling before and after digging, having good supporting effect and economic benefits.

Abstract: Water probe in coal mine working face is an important part of the work of Mine Water. When the mine working face close to the aquifer hydraulic conductivity faults, underground rivers, caves and hydraulic conductivity collapse columns; extractive damaging effects, water probe should be done. However, the calculation of water inflow face probe has no feasible way. This paper discussed the theoretical calculations to explore water drilling inflow well group interference method and provides the basis for provision of drainage system for the coal mining enterprises.

Abstract: The effect of gas extraction would be significantly increased by the way of coal section drilling hole diameter expansion. For the existing technical problems and limitating of constructing large diameter borehole directly or using the reaming way of SKP high pressure water jet, and based on heterogeneous crushing mechanism of high pressure water jet, the integrative hydraulic drilling and reaming completely technology is proposed, the system structure of the technology is researched, the main equipments are integrative selected, and the process characteristics and application prospect of the technology are concluded. The results show that the integration technology of the integrative hydraulic drilling and reaming obvious improves the permeability of coal, promotes gas release, realizes continuous drilling between coal and seam and carried out simultaneously with drilling and reaming. It could significantly increase reaming efficiency and adaptability of evil working condition, which has important popularized and applied values.

Abstract: At present, kerosene is one of the most widely used non-polar hydrocarbon oil collector agent in coal flotation in China, kerosene is difficult to dissolve in water, with good collector, but the dosage is comparatively large in the actual production.The drainage oil is from the dining recycled goods and the waste of animal flesh, can be used for preparation of fatty acid collector, which not only to reduce environmental pollution,but also to reduce the risk of food safety. At the same time, if drainage oil can replace the kerosene in coal collection, it will improve the coal preparation plant efficiency and solve the problem of shortage of national resources. In this study, we use Huangling coal as raw material for flotation experiment, use kerosene, diesel, drainage oil and emulsified drainage oil as collectors. Adding different collectors in the same flotation conditions to research the yield of clean coal, the clean coal ash and the yield of tailings by changing the dosage of collectors. The results show when adding to OP emulsifier and the proportion of water and oil is 6:4, flotation effects is the best, the yield of clean coal is 88.67%, the ash of clean coal is from 9.16% down to 8.63%, the yield of tailings is 11.32% .

Abstract: Temperature dependent solid-liquid extraction (SLE) behavior of six rare earth elements (REs) was investigated using N-butyl pyridinium hexafluorophosphate ([BPy]PF₆) as an ionic liquid solvent and benzoyl acetone (HA) as an extractant at 80 °C. Parameters including the amount of [BPy]PF₆, HA concentration, extraction time, extraction temperature and pH were investigated and optimized. The extracted species was neutral REA_(n-1)Cl (n-1 = 3 or 2) in the REⁿ⁺-[BPy]PF₆-HA SLE system. The extraction percentage of REⁿ⁺ could be 100% at stated pH and HA concentration. The recovery of REⁿ⁺ extracted into [BPy]PF₆ can be achieved using the mixture of 0.1 mol·L^-1 ClCH₂CO₂H and 0.2 mol·L^-1 HCl as stripping agents. REs were extracted into solid ionic liquid phase with smaller volume and concentrated to some extent. Furthermore the temperature dependent SLE allows to recover [BPy]PF₆ after the extraction procedures. These results indicate that the proposed procedure can be used for the preconcentration and separation of REs using [BPy]PF₆ with high melting point.

Abstract: Potassium feldspar, phosphogypsum and coke are used as raw materials to obtain soluble salts of calcined sample through mechanical grinding, roasting activation and leaching with acid. A study has been conducted on the factors that affect the leaching ratio of K₂O of calcined samples, such as the type and concentration of leaching medium, temperature, time, liquid-solid ratio. The experiments show under the conditions that concentration of citric acid of 2% (wt%), liquid-solid ratio of 4, leaching for 4 hours at room temperature, potassium dissolution rate can reach 76.81%.

Abstract: The thermal decomposition process of K-feldspar-CaSO₄-CaO system was studied by X-ray diffraction (XRD) analysis of the product which calcined at 1473K. The results show that KAlSi₃O₈ firstly is decomposed into KAlSi₂O₆ and released the SiO₂, then has a complex reaction between KAlSi₂O₆ and CaO, which generated intermediates-K₂SiO₃ under the operating conditions. K₂SiO₃ is unstable and reacted with calcium sulfate to generate K₂SO₄. When the CaO amount is insufficient, the main products are KAlSi₂O₆ and 2CaOAl₂O₃SiO₂, the potassium existed as K₂S₂O₈; when n (CaO) / n (KAS₆) 12:1, the products will further transfer into CaOSiO₂ and 2CaO SiO₂ and the potassium existed as K₂SO₄.

Abstract: Application of Combined Collectors in Flotation of Lepidolite were researched, and the object is the gravity concentration tailing of YiChun Tantalum&Niobium Mine. The experiments show: when LZ-00 dispensed by ourselves and mixed amine combined in two to one was used in lepidolite flotation, the flotation indexes is best,and the optimum dosage is 360g/t .The close circuit test can got the lepidolite concentrate with grade 4.12%, recovery 70.37% .It has a remarkable upgrading compared with the target of ore dressing plant . Infrared spectrum showed mineral surface existed chemical adsorption and physical adsorption and hydrogen bonding simultaneously when using LZ-00 and mixed amine to flotation lepidolite .

Abstract: This paper introduces the status of micro-fine weakly magnetic iron ore separation technology, analyzes the various characteristics of each separation process ,enumerates some production technology examples dealing with such iron ore and points out that the combined aggregation separation technology will have a wide development and application prospects in fine weakly magnetic iron ore sorting and processing areas.

Abstract: Based on the analysis of the properties of the copper ore from Jinggu area in Yunnan province, a suitable technical route was presented for processing of eligible copper concentrate and the main factors i.e. grinding fineness, Na2S dosage and collector dosage, affecting the quality of roughing concentration was investigated. On this basis, a close-circuit flotation test scheme was preceded, which obtained a high quality copper concentrate with Cu grade of 16.08%, copper recovery of 58.52%. The recovery of copper concentrate is much lower than the Cu recovery of roughing concentrate from the condition experiments. This may be contributed to the fact that fine slime carried by middling worsens the separation of copper minerals and gangues. The Mo was enriched in concentrate, which is significantly considered to recovery in further work.