In view of the technical conditions for Wohushan underground mine of Hualian Mining Company, nine sets of schemes were prepared with orthogonal experimental design, and a stope computation and analysis model was established based on Dimine-Midas/GTS-FLAC^3D coupling technique, with which mechanical characteristics of stope with different parameters were obtained, thus 9 evaluation indicators including the maximum tensile stress were determined. Then, a comprehensive evaluation model was established for the stope structural parameters by use of kernel principal component analysis (KPCA) and the structural parameters were optimized with the evaluating function values. Results showed that the orthogonal experimental design effectively reduced the calculated engineering quantity and improved the analysis efficiency, from which mechanical characteristics of stope with different structural parameters and with different backfilling strength were obtained. By means of KPCA, the optimal structural parameters of stope were determined as follows: pillars of 12.5 m in height and 3 m in width, stope of 10 m in width, as well as elastic modulus of 0.1 GPa for the fillings. Based on the comparison with principal component analysis, it is found that two methods can lead to the almost same evaluation results, indicating that KPCA can be used for comprehensive evaluation with multi-factors, with wide applicability.

The paper emphatically reviews the present conditions of research on pre-desilication of mid-low grade bauxite using processing methods.The methods of desilication, including the physical processing, chemical processing and biological processing, are discussed concisely, and the developing tendencies on the pre-desilication of bauxite are analysed at last.

A detailed analysis of the Li-ion cathode materials industry was presented in terms of the industry background, the status quo of development, as well as sales of global leading enterprises. After that, future development direction for this industry is put forward combined with analysis of its present development trend at home, which can be of reference for the development of lithium-ion battery cathode materials.

An introduction of principal remote sensing technology and equipment used in the process of ecological environment monitoring and law enforcement supervision was presented. After the introduction of the application of remote sensing technology to environmental monitoring, including vegetation indexes, soil pollution, air pollution, water pollution, the existed shortcomings were pointed out and direction of improvement for the application of remote sensing technology were put forward.

This paper has made a present situation review of research on high-strength and high-conductivity copper alloys.Several hotspots in this field such as high-strength and high-conductivity copper alloys prepared by rapid solidification, dispersion strengthen copper made with in-situ oxidation and Sol-Gel method, Cu-based in-situ composites, Cu-based lead frame materials and the application of rare-earth in high-strength and high-conductivity copper alloys have been introduced.It is pointed out that the precipitation strengthening and multi-micro-alloying are effective methods to increase the performance of highstrength and high-conductivity copper alloys;the copper based composite is the future development trend;the comprehensive performance and industrialization are pursued in the development of the alloys.

The influence of thermal treatment parameters, such as the heating temperature and duration, on the crystal phase transformation of γ-MnO₂ was studied. XRD patterns show that the phase transformation of γ-MnO₂ to β-MnO₂ begins at 300℃ and completes after the sample was heated at 350～450 ℃ for 5～20 h. After heated at 560 ℃ for 2 h, Mn₂O₃ appears, and its content can reach 75.63% when heated for 20 h at this temperature. It can be concluded that the temperature is the primary parameter influencing the phase transformation of MnO₂.

The preparation of Cu₂O powder by the way of reduction in reducing atmosphere, electrolytic process and hydrometallurgy is introduced.In the industry practice, Cu₂O powder is mainly made by electrolytic process, and the powder is characterized by good dispersivity and fine particles, the wet process is focused recently and several methods has been found to prepare cu₂O powder by hydrometallurgy.

A description is made of main application fields, present domestic and foreign development state and marketing prospects of alumina fibre, and a new method is given for preparing alumina fibre.

A brief introduction about the recent progress in the research of structural design and synthesis technique of precursors for ternary cathode materials was presented. It was concluded that a rational precursor design and optimized synthesis technique could enhance the electrochemical performance of cathode materials, and the synthesized cathode materials could satisfy the requirements for high-performance batteries.

Pore forming methods of ceramic material is described briefly. The applications and prospects are outlined in mining, metallurgy, enengy sources, environmental protection, food processing and biomedicine.

The determination of Ni, Co and Mn content in Li-ion battery cathode material Li_δNi_1-x-yCo_xMn_yO₂ was studied by instrumental analysis method and chemical analysis method. The Ni was determined by high concentration of condifferential absorption spectrophotometry, Mn was determined by REDOX titration, and Co was determined by gravimetric method. Higher experimental precision was obtained by optimizing the experimental conditions. A recovery of 97.61%~101.0% was achieved, and the relative standard deviation was below 0.49%. This method is accurate and exact, which can be applied to quality control in large-scale manufacture.

Synthesizing methods of cathode material LiCoO₂ for lithium-ion battery and its advances in doping research were reviewed.After analyzing the disadvantages such as high price, toxicity and low actual capacity, the authors give two ways to improve its cost performance.One is looking for new synthesizing methods, and the other is doping some elements into LiCoO₂.

The model of mineral melting was built up on the basis of redefining melting point and melting state. A mathematical formula between melting point of material and its particle radius was deduced by applying the relations between the changes of energy conservation and surface energy. The change regularities on void fraction and density of powder material were revealed mathematically.

The developments of high strength and toughness aluminum alloy are reviewed in this paper in detail.The authors discuss the relations between its microstructures and properties as well as key mechanism of strengthening aluminum alloy.Some new heat treatment techniques, such as solutionizing, regression and reageing, etc are introduced.Some proposals are made for its futural, development and research.

The organic depressors for depressing arsenopyrite include small and large molecular organic depressors.The relationship between the structures and activities of the depressors are discussed.The structures and the effects on arsenopyrite in sulfide flotation of small and large molecular organic depressors are illuminated, respectively.

The principles, advantages and disadvantages on recent treatment technology of ammonia-nitrogen wastewater were overviewed. The research status at home and abroad was introduced. The prospects of ammonia-nitrogen wastewater treatment was looked forward and considerable problems for the future were proposed.

The routs used to improve the mechanical property of alumina ceramics in recent years have been reviewed.A way for preparation of alumina ceramics with high fracture toughness by comprehensively using nanotechnology and composite engineering to optimize the interface and microstructure of the material has been proposed.

Novel nickel-free cold sealing K₂ZrF₆ based of anodized aluminum was developed.The influences of K₂ZrF₆, F^- concentration, pH value of sealing solution and sealing time on sealing were studied.The Stability of bath and sealing quality was increased by adding certain amount of F^-(about 0.2 g/L)in the sealing bath.The experimental results shows that the process could not only be operated effectively at relatively low fluoride content but also reduce or retard smut and green film surface produced by Ni-F sealing process.

A theoretical analysis is made of the nucleation and growth mechanisms of calcium carbonate whiskers.By monitoring changes in pH value and conductivity during reaction and SEM observation of the samples taken at differemt times, the authors discuss their crystallization process.

Current investigations and the application potentials of the resourcing technology to utilize mining gangue, mineral processing tailings and metallurgical slag were reviewed. The technical problems and the possible solutions in using non-metal minerals in the solid wastes as environmental materials, the comprehensive recovery of special blast furnace slag containing Th, Ti and rare earths, the application of steel slag as active admixtures for cement concretes, have been discussed. It is concluded that the efficient separation of ultrafine particles plays a crucial role in improving utilization effectiveness of solid wastes as a secondary resource and worth receiving more attention.

Using sodium hydrosulfide as the sulfidisation reagent, sodium silicate and CMC as the combined depressant, Y-89 as the collector and MIBC as the frother, a flowsheet consisting of a pre-flotation desilming and a NaHS-induced simultaneous flotation has been selected to treat a composite copper-cobalt ore. When the grades of copper and cobalt are 1.14% and 0.18% for the run-of-mine ore, the copper grade and recovery in the concentrate attained 24.78% and 72.66%, respectively, while the cobalt grade and recovery reached 2.75% and 51.10%, respectively. According to the mechanism analysis on the sulfidisation reagent induced flotation of oxide ore, HS^- is the most functional component in sulfidisation reagents. Both NaHS and Na₂S show excellent adaptability in the flotation of copper minerals, but with the same dosage, the cobalt minerals can be better recovered by the former as a much more stable metal sulfide film can be formed on the surface of cobalt minerals.

综述了碳酸钙晶须的物化性质；详细介绍了国内外碳酸钙晶须的制备方法(可溶性钙盐与碳酸盐反应制备法、碳酸氢钙水热分解法、尿素水解法、碳酸化法，超重力反应结晶法和磷石膏水热合成法)研究进展，并评述了各种方法的优缺点。介绍了晶型控制剂MgCl₂、AlCl₃ 和可溶性磷酸盐在碳酸钙晶须制备过程中的作用机理。综述了碳酸钙晶须的表面改性及其在塑料、造纸、涂料和摩擦材料等领域的应用研究进展。最后指出了碳酸钙晶须研究中存在的问题及发展方向。

Atomicforce microscope is a essential tool which can be used for investigating microstructure of materials on nanometer scale or at molecular level.A description is made of its basic principles, operating patterns, techical characteristics and application.

The thermal decomposition behavior of cobalt oxalate dehydrate(CoC₂O₄·2H₂O) was studied with  thermogravimetry analysis(TG-DTG) and differential scanning calorimetry(DSC) in Ar or Air atmosphere  respectively. And the thermal decomposition behavior of cobalt oxalate was analyzed and discussed from thermodynamics point of view. The result shows that the thermal decomposed products of cobalt oxalate are  metallic cobalt in inert atmosphere, while the products are Co₃O₄ in oxidizing atmosphere when  the  temperature is below 700 ℃. The thermodynamics analysis results are verified by DSC-TGA curves.

Conductive silver paste was prepared with the mixture of silver powder, glass powder and organic vehicle.With variant content of some organic acid and different sintering process, the effects of organic acid content, sintering tempertature and sintering time on conductive properties of Ag film were discussed  by observing the morphology of the paste sintered Ag film with SEM and measuring the resistivity with the four point probe meter. The results show that conductive silver film with good performance can be obtained with the organic acid's mass fraction at 1.22%, sintering temperature at 700 ℃ and holding temperature time at 15 min.

The synthesizing methods and present application status of the oxide ceramic fiber are reviewed, and the main development directions are pointed out.

The methods of replacing gold with zinc, absorbing gold with active carbon, and recovering gold by electrolysis were studied. At the same time, the methods of recovering iodine by electrolysis were investigated. The results showed that it is feasible to recover gold by active carbon absorption and electrolytic process and recover iodine by electrolysis.

Ultrafine CeO₂ powder was prepared using NH₄HCO₃ as precipitating agent.The results of X-ray diffraction show that CeO₂ nanometer crystals obtained at 300～900 ℃ are cubic crystals, of which the mean size increases with the roasting temperature.The weightlessness rate of the sample depends mainly on its roasting temperature.At a reactant concentration of 0.25～0.3 mol/L, a precipitatant concentration of 0.2～0.4 mol/L, a solution pH of 7～8, a precipitation temperature of 60～80 ℃ and a roasting temperature of 600 ℃, ultrafine CeO₂ powders can be prepared with a mean size of 20 nm and good dispersibility.

The mechanisms of microalloying and composite microalloying of rare earth in aluminum alloy were described. It was pointed out that future studies will focus on the interaction and multilevel structure between rare earth and other solute atoms and the establishment of composite microalloying theory and correlative model.

A systematic introduction was made to the refining methods for A1-Si alloy, including modification, spray forming, solution treatment, sloping plate casting and high solidification temperature gradient semi-continuous casting. It is pointed out that enhancing cooling capacity, achieving high solidification temperature gradient and undercooling the interface can remarkably refine the alloy and its primary silicon to obtain high performance A1-Si alloy.

The fused salt electrolysis process and ferrosilicon thermal reduction process for the production of magnesium were briefly introduced. Discussions were made on the problems of dehydration of MgCl₂·6H₂O, impurity in metal magnesium and safety in electrolysis production of magnesium and the problems of energy consumption and environmental protection in pidgion process. Advances in the development of magnesium productions by electrolysis. Pidgion process and direct electrolysis of MgO were summarized. A plan for producing of Al-Mg master alloy by direct electrolysis of MgO in cell was put forward.

The debinding and sintering process in the powder injection molding(PIM)of Kovar alloy has been investigated here.The results show that all the binder can be removed rapidly and effectively by the solvent debinding and thermal debinding, PIM Kovar alloy packing box with an average thermal expansion coefficient of 5.75 ×10^-6/ ℃over the range of 25 ℃to 400 ℃ can be obtained after sintering.Both metallurgical microsructure and X-ray diffraction analysis show that the alloy is composed of austenititephase (γphase)and a little ferrite phase (αphase), while the existence of αphase mainly results in the higher thermal expanxion coefficient of PIM Kovar alloy.

The synthetizing and purification methods of N-methyl-2-pyrrolidone are introduced.A comparison is made of the performances between N-methyl-2-pyrrolidone and commonly-used organic solutions in lithium batteries.The authors describe the applications of N-methyl-2-pyrrolidone in lithium batteries and liquid crystals, etc, and look forward to the futurel prospects for synthesization and application of N-methyl-2-pyrrolidone.

The present status and recent advances of the study of graphitization degree of C/C composites have been reviewed from three aspects:the detection and charaterization of graphitization degree 、the effecting factors of graphitization degree and the effects of graphitization degree on the properties of C/C composites.It is concluded that there has been no generally-accepted standards for detection and charaterization of graphitization degree of C/C composites.It is essential to systematically trace 、analyze and study the structural tranformation of the different elements and their interfaces in C/C composites in graphitization and the effects of this structural transformation on the properties of C/C composites.

The process methods and characteristics of zinc oxide ores are introduced. There are two ways to deal with it. One is that zinc oxide ores are enriched by mineral processing and then smelted to obtain metal zinc. The other is that zinc oxide ores are directly treated by smelting which can be divided into pyro-metallurgy and hydro-metallurgy. The expectation of application prospects of zinc oxide ores' treatment technology is carried out.

As a kind of important structural materials in the aeronautic industry, Ti and Ti alloys have excellent mechanical properties at cryogenic temperature.The mechanical properties such as tensile strength, fatigue strength, fracture toughness, charpy impact absorbed energy at cryogenic temperature for Ti and Ti alloys, and their response to temperature and material composition were reviewed in this paper.In addition, some advice about the use of Ti and Ti alloys at cryogenic temperature was given.

Casting mechanical properties and corrosion behaviour of Al-7.1Si-0.3Mg (A), Al-6.5Mg-0.8Ti (B), Al-8.58Mg-1.4Zn-0.07Ti (C), Al-10.9Mg-0.09Ti (D), Al-2.5Si-2.1Mg-0.8Mn-0.2Cr (E)were investigated.The results indicate that these Al alloys had good mechanical characteristics.The alloy A had excellent casting properties whilst poor in corrosion-resistance.The alloys B, C, D exhibited a high corrosion-resistance but inferior in casting properties and SCC.The alloy E showed outstanding corrosion-resistance and other comprehensive properties due to appropriate Mg and Si in it.

Additive has an important effect on copper electrolytical production.According to the experiences in copper electrolytical production and varoius factors affecting the technical performance of electrolytical operation, the author sums up and discusses its role and applications in practical production.

The extraction electrodeposition process is used to treat gold concentrate to recover copper.It has been successfully applied in production practice.The copper obtained by the process comes up to class I of national quality standards, that is to say, a Cu extraction ratio is up to 96.95%.The production practice shows that the process is characterized by good economic results and convenient operation and it is well worth appliying in the same industry.