Papers by Keyword: Serpentine

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Authors: Leonid Skipin, Vera Petukhova, Elena Gaevaya, Elena Zakharova, Aleksandr Mitrikovskiy
Abstract: The paper presents the study on the physical properties of the cuttings. Culvert capacity of the drill cuttings with different coagulants is considered. The water permeability of the studied samples varies depending on the quality of the composition and the dosage of a coagulant used. The coagulants have been proposed as aluminium sulphate, iron sulphate, calcium chloride, gypsum, phosphogypsum, serpentine, blast furnace slag, calcium carbonate and carnallite. Iron and aluminium sulphates, calcium chloride, gypsum and phosphogypsum appear to be the most effective when acting on the water permeability in the drill cuttings. With regard to the variants incorporating the complete response curve, the optimal dose of ameliorant can be determined after maximum filtration of water in the column. This method allows the dose of coagulant to be determined by the filtration threshold. The optimal dose for iron sulphate is 0.8 g; with this parameter the volume of filtered water reaches 16.80 ml / day.The use of effective coagulants allows displacement of sodium and potassium cations from the absorption complex and fundamentally improves its physical and chemical properties; this is clearly seen by the change of the filtration capacity of the considered sample. Phosphogypsum – a waste material of chemical industry of Ural chemical plants - is of the greatest interest. It can significantly improve the properties of the considered sample when transforming two waste materials (drill cuttings and phosphogypsum) to a neutral environmentally-friendly state.
Authors: A.P. Qiu, Y. Su, S.R. Wang, B.L. Zhou
Abstract: The design of mechanical structures depends upon characterizing the stress/strain state in these devices under the combined influence of both loading and residual stresses. The performance of the dynamic structures is strongly influenced by residual stresses. Understanding of the behavior of gyroscopes in presence of residual stresses and ability to relieve the stresses are essential for improving the performance. In this paper, we briefly analyze the cause of residual stresses. The effect of residual stresses on natural frequencies of the drive mode and sense mode is theoretically analyzed. The FE model of the z-axis gyroscope is built to investigate the relation between the frequencies and the residual stress by model analysis. Methods for residual stress relief are presented. The results of the simulation demonstrate that the performance of the gyroscopes with serpentine beams and stress relief slots can be improved significantly.
Authors: Shuai Ping Shen, Zhi Tao Yuan, Li Xia Li, Shuo Zhu
Abstract: The useful minerals of Jinchuan high-grade copper and nickel suphfide ores were mainly nickel and copper, whose grade were respectively 1.42% and 1.01%. The content of MgO and SiO2, main gangue components, reached 57.89%. The key to improve the separation indexes of flotation concentrate was to inhibit the gangue minerals effectively, therefore, the effects of different kinds of regulators on Jinchuan high grade copper-nickel ores by flotation were studied. Considering the grade and recovery of concentrate comprehensively, the optimal regulator of mineral flotation was determined to be the combination of sodium hexametaphosphate and citric acid, and the dosage were 300g/t and 500g/t, respectively. After analyzing the mechanism of the two regulators, the combined reagents could reduce the isoelectric point of gangue minerals, decreasing the adsorption between gangue minerals and valuable minerals. In addition, the reagents were able to eliminate the activation of useless ions such as Ca2+ and Ni2+ on the gangue minerals and improve the ion composition of pulp, increasing the difference of floatability between gangue and useful minerals.
Authors: Da Yong Sun, Wan Zhong Yin, De Shan Zhu, Ming Bao Liu, Xi Mei Luo
Abstract: In alkaline condition, experiments were taken to investigate the influence of different regulators on the flotation behaviors of brucite and serpentine when sodium oleate was the collector. The regulators used in experiments included sodium silicate, tannin and calcium lignosulphonate. The results showed that sodium silicate had a great effect on the flotation. When the regulator was the sodium silicate, serpentine recovery rate was less than 10% and brucite recovery was about 90% in the pH of 10. After analysis, brucite and serpentine may be separated effectively by sodium silicate. At last, the function mechanism of sodium silicate was probed. The electrostatic adhesion between serpentine and sodium silicate accured, and the surface of serpentine was negative so that it was difficult to be collected by sodium oleate; Instead, the impact of sodium silicate on brucite was weak, and the surface of brucite was still positive so that it could be collected easily.
Authors: Bin Ma, Zhao Hui Huang, Ming Hao Fang, Yang Ai Liu, Shu Sen Chen
Abstract: In order to obtain the porous silicon, amorphous silica was prepared from serpentine by leaching experiment The XRF results shows that the leach residues almost compose of amorphous silica, the content is 92.37%, via magnesiothermic reduction, The XRD results shows the amorphous silica was reduced to porous crystal silicon successfully and The SEM results shows they have similar morphology. One of the most important properties of porous silicon was characterized by PL and with an excitation at 365 nm. an emission centered in the blue region.
Authors: De Hong Xia, Ling Ren, Yi Fan Li
Abstract: The traditional silicothermic process of magnesium metallurgy with dolomite at high temperature and under high vacuum condition results in high operation costs, discontinuous production and huge production consumption. Based on this, a new thermal reduction process of magnesium preparation is proposed with serpentine as raw material at ordinary pressure. It is shown by thermodynamic analysis that the calcined products of serpentine is the compound of 2MgO•SiO2 and MgO•SiO2. Furthermore, the thermal reduction process at ordinary pressure is determined by using calcined products of serpentine as raw material, CaC2 as reductant and CaO as additive. Comparing with traditional silicothermic process, the new process has many advantages due to higher magnesium content of serpentine, lower price of the reductant CaC2, lower reaction temperature in calcined and thermal reduction process, and ordinary pressure reaction conditions for continuous production.
Authors: Misran Erni, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: Flow field design has several functions that should perform simultaneously. Therefore, specific plate materials and channel designs are needed to enhance the performance of proton exchange membrane (PEM) fuel cell. Serpentine flow field design is one of the most popular channel configurations for PEM fuel cell system. Some configurations have been developed to improve the cell performance. This paper presents a review on serpentine flow field (SFF) design and its influence to PEM fuel cell performance based on some indicators of performance. The comparisons of SFF with other flow field designs are summarized. The results of some experimental and numerical investigations are also presented.
Authors: Qian Yu Tang, Hua Wang, Hui Tao Wang, Shan Qing
Abstract: Due to the conventional flat plate solar collector has low efficient, it is necessary to make some improvements in the structure of conventional flat solar collector. This research improved the structure of conventional flat solar collector and conducted thermal performance testing for the improved structure which is serpentine heat pipe flat plate solar collector. The test results indicate that serpentine heat pipe flat plate solar collector has higher efficient than conventional solar collector. Thus, serpentine has better economic and environmental benefit than conventional solar collector.
Authors: Evgeny N. Selivanov, S.V. Lazareva, L.U. Udoeva, R.I. Gulyaeva
Abstract: The article is devoted to an estimation of phase transformations of silicates magnesium at heating in the temperatures range from 0°C to 1100°С. The object of study is a silicates of magnesium containing oxide nickel ore. Differentially-thermal (NETZSCH 449 C - Jupiter), weights – spectrometer (QMS 403 C Aёolos), high-temperature X-ray diffraction, electron-probe microanalysis (JSM - 5900 LV) and chemical analysis methods have been used in the study. The temperature ranges of existence Mg6[(OH)8Si4O10] and Mg2Si2O6 are obtained. Parameters of an elementary cell of the above minerals and their changes with temperature and features of nickel distribution in magnesium silicates with various ration MgO/SiO2 are defined in this work.
Authors: Bei Song, Yu Ran Zhang, Yong Hao Di, Rui Dai, Shui Lin Zheng
Abstract: The research involves the calcination of QingHaiQiLian serpentine with ammonium sulfate in order to extract magnesium, and evaluates calcination results through the mass of water leaching residue that comes from the calcination, dissolution and filtration process. Optimal calcination parameters of serpentine and ammonium sulfate determined by orthogonal experiments, single-factor experiments, elemental analysis and SEM analysis are: calcination duration of 1h, calcination temperature of 700°C, ammonium sulfate dosage of 90g (or mass ratio of ammonium sulfate to serpentine sample (m1/m2) of 3:2), under which condition a magnesium extraction rate of 62.75% can be achieved.
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