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Han Z.,GuangZhou Research Institute of Nonferrous Metals | Gao Y.,GuangZhou Research Institute of Nonferrous Metals | Wang G.,GuangZhou Research Institute of Nonferrous Metals | Xu X.,GuangZhou Research Institute of Nonferrous Metals
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2012

The action law of wolframite as functions of four collectors and combinative collectors which were chelating collector GYB and fatty acid collectors NaOL, HPC, 731 was investigated by flotation experiments of pure mineral. Experimental results of wolframite flotation by single collector showed that the best flotation pH interval of NaOL was narrowed in alkalinity and the best flotation pH of GYB, HPC, 731 approximated from weak acidic to weak alkaline interval. Experimental results of wolframite flotation by combinative collector showed the collecting capability to wolframite was enhanced with the combinative of chelating collector GYB and fatty acid collectors NaOL, HPC and 731, in which GYB played a supporting role and obvious synergistic effect made by low dosage. When cGYB:cHPC:c731=1:6:3, the best collecting ability was gained and the flotation pH interval of wolframite was broaden in 4~10 with better floatability. Influence research on wolframite hydrophobic behavior by combinative collectors was discussed as functions of surface wettability measurements and hydrophobic aggregation behavior. Results of surface hydrophobic properties measurement of wolframite showed that the contact angle of wolframite was bigger and increased to 82.8°with cGYB:cHPC:c731=1:6:3 and pH≈6.5, the enhancement of surface hydrophobicity and the aggregation was bigger and tighter.


Li B.,GuangZhou Research Institute of Nonferrous Metals | Liang D.,GuangZhou Research Institute of Nonferrous Metals | Zhang L.,GuangZhou Research Institute of Nonferrous Metals
Zhongguo Xitu Xuebao/Journal of the Chinese Rare Earth Society | Year: 2012

Process mineralogy of an apatite-rich complex rare earth ore was investigated by chemical analysis, microscope and international advance automatic quantitative mineral technology MLA. The results indicated that the rare earth minerals mainly were bastnaesite and allanite, secondly were monazite and parasite. In addition, there was a large quantity of rare earth existed in apatite, which occupied above 26% of total rare earth in the crude ore. It was decided that the commercial rare earth concentrates cannot be got only using physical processing according to the properties of this rare earth ore, so flotation separation and flotation-magnetic separation combination could be adopted to separately get apatite concentrates and rare earth concentrates, and then roasting and leaching could be adopted to extract rare earth elements.


Xu L.-P.,GuangZhou Research Institute of Nonferrous Metals | Zhang E.-L.,Jiamusi University | Yang K.,CAS Shenyang Institute of Metal Research
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2012

Calcium phosphate coated Mg alloy was prepared. The phase constitute and surface morphology were identified and observed by X-ray diffractometer (XRD) and SEM. The results show that the coating is composed of flake-like CaHPO 4·2H 2O crystals. The corrosion resistance of the coated Mg alloy was measured by electrochemical polarization and immersion test in comparison with uncoated Mg alloy. Cytocompatibility was designed by observing the attachment, growth and proliferation of L929 cell on both coated and uncoated Mg alloy samples. The results display that the corrosion resistance of the coated Mg alloy is better than that of uncoated one. The immersion test also shows that the calcium phosphate coating can mitigate the corrosion of Mg alloy substrate, and tends to transform into hydroxyapatite (HA). Compared with uncoated Mg alloy, L929 cells exhibit good adherence, growth and proliferation characteristics on the coated Mg alloy, indicating that the cytocompatibility is significantly improved with the calcium phosphate coating.


Zhonghan Z.,GuangZhou Research Institute of Nonferrous Metals | Xianghua Z.,GuangZhou Research Institute of Nonferrous Metals
26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings | Year: 2012

A domestic tungsten-tin ore presents very complex property. How to effectively recover the scheelite, wolframite and cassiterite in the ore has long been a difficult problem to be solved urgently. On the basis of process mineralogy study, a main flow-sheet for effective recovery of tungsten-tin minerals has been developed, which including "fine grinding of feed-bulk flotation of all sulfides followed by their selective separation-iron recovery by LIMS-tungsten-tin minerals bulk flotation using new technique developed by our institute-tungsten-tin recovery by gravity from above tungsten-tin bulk flotation tailings". As for the treatment of tungsten-tin bulk rougher concentrate, several flow-sheets of tungsten-tin separation by direct hydrometallurgy or a flow-sheet consisting of scheelite cleaning at elevated temperature followed by the gravity separation of scheelite cleaner tailing-separation of wolframite from cassiterite by dry HIMS or by direct hydrometallurgy are developed. For a low grade head ore, all valuable sulfide, magnetite, scheelite, wolframite and cassiterite are recovered with satisfactory in lab scale test.


Tang Y.,GuangZhou Research Institute of Nonferrous Metals | Zhang J.,GuangZhou Research Institute of Nonferrous Metals
26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings | Year: 2012

High Gradient Magnetic Separator with Horizontal Magnetic Line is a new type High Gradient Magnetic Separator product. It has many specific advantages, such as water-air joint discharging technique, double pulses pulp dispersion technique, multi-magnetic gradient for collecting matrix with different diameter rods, better discharging rate with the especial matrix dispose, high separating accuracy and wide applicability. In this paper, the author makes a description of High Gradient Magnetic Separator with Horizontal Magnetic Line, and puts its emphasis on analyzing industrial production data using high gradient magnetic separator with Horizontal Magnetic Line to separate weakly magnetic minerals. It is found that as the rougher for weakly magnetic minerals separation, High Gradient Magnetic Separator with Horizontal Magnetic Line has more stable metallurgical performance and cheaper running costs than other types of High Gradient Magnetic Separator when the properties of the ore change greatly and there is in the case of embedded fine particle size distribution.


Yan Z.,GuangZhou Research Institute of Nonferrous Metals | Chen F.,GuangZhou Research Institute of Nonferrous Metals | Cai Y.,GuangZhou Research Institute of Nonferrous Metals | Cui L.,GuangZhou Research Institute of Nonferrous Metals
Jinshu Xuebao/ Acta Metallurgica Sinica | Year: 2010

High velocity compaction (HVC) is a recently developed technology for forming high density metallic parts with high efficiency, whose densification is realized through the strong impact wave generated by liquid-pressure controlled by heavy hamper. This technology is thought to have an excellent balance between properties and cost and has several advantages over other existing forming technologies, including high and homogeneous green density, low cost, low springback and high precision. It is extremely competitive to prepare powder metallurgy parts with high density, high strength, high precision and low cost. With a high hardening rate, Ti powder is difficult to be formed through traditional pressing methods, although advanced forming methods are effective for increasing its density, such as hot-pressing and isothermal-statistic pressing, they are very expensive. HVC would thus be highly attractive to solve these problems of low density and high cost in forming Ti powder. In this paper, the process of HVC forming Ti powder was studied. Two kinds of samples, the rings with 60 mm outer and 30 mm inner diameters and the cylindricals with 20 mm diameter were prepared through HVC, respectively. The influences of impact energy and filling weight on the green density were investigated. The results show that, for the ring samples, the maximum of green density is 4.00 g/cm3 and its relative density is 88.9% at an impact energy of 3.804 kJ. However, for the cylindrical samples, the maximum of green density is 4.38 g/cm3 and its relative density is 97.4% at an impact energy of 1.217 kJ. For the both kinds of samples, the green density increases with increasing impact energy while decreases with increasing filling weight. Impact energy per weight is helpful to characterize the green density obtained at different dimension, impact energy and filling weight. ©.


Zhang J.,GuangZhou Research Institute of Nonferrous Metals | Deng C.,GuangZhou Research Institute of Nonferrous Metals | Song J.,GuangZhou Research Institute of Nonferrous Metals | Liu M.,GuangZhou Research Institute of Nonferrous Metals | Zhou K.,GuangZhou Research Institute of Nonferrous Metals
Surface and Coatings Technology | Year: 2013

Erosion of sink rolls by molten zinc is one of the most prominent and persistent problems occurring in hot-dip galvanizing industry. MoB-CoCr as an alternative to WC-12Co for stainless steel protective coating resistance to molten zinc was deposited by high velocity oxygen fuel (HVOF). Microstructure and mechanical characterization of the coatings were carried out by SEM, XRD and micro-hardness test. Resistance to thermal shock and molten zinc corrosion of the coatings were also conducted. Results showed that MoB-CoCr coating exhibited a better resistance property to thermal shock than that of WC-12Co. At the same time, the corrosion test showed that lifetime of samples with MoB-CoCr coatings in molten zinc appeared to be longer than that of WC coating. The corrosion resistance of MoB-CoCr coating may be ascribed to non-wettability of MoB-CoCr in molten zinc, which can delay the molten zinc penetration into substrates along the micro-cracks of the coating. © 2013 Elsevier B.V.


Wang S.,GuangZhou Research Institute of Nonferrous Metals | Song D.,GuangZhou Research Institute of Nonferrous Metals | Xu J.,GuangZhou Research Institute of Nonferrous Metals | Zheng K.,GuangZhou Research Institute of Nonferrous Metals
Materials Science Forum | Year: 2016

In the present investigation the casting-forging integrated technology was adopted to manufacture Al-1.1Mg-0.6Si-0.4Cu alloy automobile brake calipers. The effect of forging pressure on the microstructure and mechanical properties of Al-1.1Mg-0.6Si-0.4Cu alloy calipers were studied. The results showed that the shrinkage porosities and cracks in the Al-1.1Mg-0.6Si-0.4Cu alloy calipers could be removed by the forging process. The ultimate tensile strength and elongation of Al-1.1Mg-0.6Si-0.4Cu alloy calipers increased with the increase of forging pressure. When the forging pressure was 120 MPa, the ultimate tensile strength and elongation of Al-1.1Mg-0.6Si-0.4Cu alloy calipers with T6 heat treatment were 365.3 MPa and 11.5%, which were improved by 22.8% and 38.2%, respectively compared with that of Al-1.1Mg-0.6Si-0.4Cu alloy calipers without forging. The tensile fracture images revealed that the fracture modes of Al-1.1Mg-0.6Si-0.4Cu alloy calipers were more ductile at higher forging pressure. © 2016 Trans Tech Publications, Switzerland.


Yan Z.,GuangZhou Research Institute of Nonferrous Metals | Chen F.,Hong Kong Polytechnic University | Cai Y.,GuangZhou Research Institute of Nonferrous Metals
Powder Technology | Year: 2011

Pure titanium powder was pressed into two kinds of samples through high-velocity compaction technology. The first was rings with 60. mm outer and 30. mm inner diameters and a mass of 57. g, and the second was cylinders with 20. mm diameter and a mass of 10. g. For the rings, the maximum shapable relative density reached 76.2% at impact energy of 2283. J. For the cylinders, however, it reached 96.0% at much lower impact energy of 1217. J. The reasons for the contradictory effects were analyzed, and a new quantity, impact energy per unit mass, was put forth to well characterize the difference. In addition, the relations between peak pressure and green density of the two kinds of samples were found to comply with Huang Pei-yun equation, and the densification mechanism was discussed. © 2010 Elsevier B.V.


Yan Z.,GuangZhou Research Institute of Nonferrous Metals | Yan Z.,Central South University | Chen F.,GuangZhou Research Institute of Nonferrous Metals | Cai Y.,GuangZhou Research Institute of Nonferrous Metals
Jinshu Xuebao/Acta Metallurgica Sinica | Year: 2012

The Ti powder forming is more difficult through traditional pressing methods due to inductile and high hardening rate of Ti. Some advanced forming methods, although, are effective for increasing the green density, such as hot-pressing and isothermal-statistic pressing, they are too expensive. In our previous research, it has been demonstrated that compacting high green density of Ti powders would be achieved by high velocity compaction (HVC) which seems to be an attractive candidate that has an excellent balance between performance and cost in forming Ti powders. In this paper, the four Ti powders with average particle size of 150, 75, 48 and 38 μm, namely A, B, C, and D powder, were separately pressed by HVC technology. The influences of particle size on the green density, the maximum impact force and withdraw force in compacting were investigated. The compactability features of the four powders in HVC and the properties of sintered samples were studied. The results show that the green density of compacts obtained by HVC method is related with both particle size and apparent density. At relatively small impact energy, the green density of compacts is mainly determined by the apparent density of powders. While at larger impact energy, it is mainly determined by the particle size. For powders pressed at impact energy lower than 761 J, the highest green density is obtained for compacts made of B powders which has maximum apparent density. With higher impact energy, the highest green density is obtained for compacts made of A powder which has maximum particle size. It is found that the influence of particle size on the maximum impact force is similar to those on the green density, and for the four powders the relationships between the maximum impact force and the green density all comply with Huang Pei-yun equation. Particle size shows no observable influence on withdraw force. The sintered density increases with decreasing particle size of powders, accompanying with grain growth of different degrees. After vacuum sintering at 1250°C, nearly fully dense samples can be prepared for the compacts of four powders. © Rright.

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