Advanced Materials Research Vol. 454

Abstract: WC/Co; Composite coating; Plasma spraying; Friction and wear Abstract: WC- Co composite powders were synthesized by direct mechanical grinding in a rotary-vibration mill under 8h, and then analyzed by SEM and XRD. WC and WC/Co composite coatings were prepared by supersonic plasma spraying fine WC-Co composite powders. The wear and friction properties of both coatings were evaluated. The results showed that the wear resistance of the WC/Co composite coating was superior to that of the WC coating. The improvement in wear resistance of the WC/Co composite coating was attributed to its higher fracture toughness and adhesion strength as well as better thermal diffusivity. As for the WC/Co composite coating, the mechanism was mainly adhesion with micro-abrasion and fatigued-induced brittle fracture within splats, and the delamination along splat boundaries only occurred at high load. However, the failure of the WC coating was predominantly detachment of transferred film and brittle fracture within the splats and delamination along splat boundaries, which were enhanced with the increasing load.

Abstract: The internal parameters of ball mill are very important in the grinding process and have significant impact on the grinding results. Accurate measurement of the internal parameters of ball mill is crucial and indispensable for optimization and control of grinding process. In this paper, a novel tri-sensor measurement method was used to measure the external signals (i.e., bearing pressure, sound intensity and power consumption) of ball mill. Mathematical models, which link the external signals of ball mill with its internal parameters, were established to predict the internal parameters of ball mill. Experimental results showed that the mathematical models could directly predict the internal parameters of ball mill once the external signals were obtained. The tri-sensor measurement method and the mathematical models proposed in this paper provided a new way and solid basis for optimization and control of ball milling.

Abstract: This test is in relation to a low-grade co-selected and mixed concentrates that produced from weak magnetic– magnetic beneficiation. Through the flotation tests step by step and control of variables to study the changes of starch’s amount and inhibitor collector’s amount in the impact of test results in the anti-flotation and the flotation process At the end, we received a grade of 55.65%, 57.19% recovery of iron ore products, iron ore products calcined at 800 °C for 40min under the conditions you can get concentrate grade of 60.14% of the product.

Abstract: This paper summarizes the result of experiment that was fourced on investigation of oxidation pretreatment on sulfide mineral for leaching of refractory gold concentrate by hydrogen peroxide in sulfuric acid. For a viable option, extraction rate of Fe, Cu was low, but extraction rate of arsenic reached nearly 100%. As the result of oxidation, elemental sulfur was not produced.

Abstract: Magnesia is a widely used inorganic chemical product. magnesite is an advantageous resource in China, and also an important source of magnesia. There are tree methods to making magnesia from magnesite using heat treatment. They are light burning, dead burning and melt. In recent years, domestic researches have been done on processes, product performance and process mechanism of these methods.

Abstract: This study investigated the flotation in sodium dodecyl benzene sulfonate system, the effects of phytic acid on talc flotation mechanism, then proposed a new flowsheet to handle this kind talc ore, namely “one roughing-three cleaning-one scavenging’’. The closed-circle flotation test in laboratory can obtain a concentrate with the SiO2 and CaO grade of the concentrate is 61.87% and 0.60%, the SiO2 recovery is 72.59%, removal rate of tremolitei is 95.85%. This paper improved the economic value of the talc containing asbestos, laid the foundation of industrial applications.

Abstract: Fly ash roasted by different temperature, XRD analysis of fly ash after roasting, specific surface area and pore properties of fly ash roasted before and after were tested. Results showed that roasting influenced significantly on pore properties of fly ash; Specific surface area, pore volume and amount of middle pore of fly ash increased with roasting temperature increased , then reached maximum at 700 °C, and decreased with roasting temperature increased.

Abstract: On the basis of analyzing sample properties of lead-zinc ore, the optimum experimental condition combination was obtained from systematic experimental studies of the conditions. The experimental condition combination was validated by the full process closed-circuit experiment, which showed that the good separation indexes on lead grade of 59.78% in lead concentrates, the lead recovery of 87.50%, and zinc concentrate grade of 56.33%, the zinc recovery of 93.60%, and sulfur concentrate contained 0.50% of lead, 0.47% of zinc.

Abstract: Along with the continuously rose of the iron ore price and the Chinese iron ore quantity demanded, Iron ore self-sufficient rate has become the bottleneck of Chinese steel industry development. In order to increase Chinese ore self-sufficiency rate, the paper study the xinjiang region low grade specularite. When the crude ore grade is 35%, the mass percent of reducing agent pulverized coal is 12%, roasting temperature is 800°C，roasting time is 50 min, milling fineness is 90% passing 0.074 mm and the magnetic induction is 84kA/m, after a low intensity magnetic separation, the iron concentrate can be got whose yield is 42.83%, grade is 62.04% and recovery is 79.26%.

Abstract: During practical production, siderite has an influence on flotation efficiency to hematite and magnetite. In flotation system of dodecylamine, this paper studied the flotation properties of single minerals such as magnetite, martite and quartz firstly. On this basis, the influence of siderite to flotation efficiency of martite-quartz and magnetite-quartz mixed ores was discussed. The result shows that siderite will seriously effect on the flotation efficiency of hematite (magnetite)-quartz mixed ores. Increasing the amount of starch will weaken the impact of siderite to some extent.