Applied Mechanics and Materials Vols. 295-298

Abstract: This paper, a comprehensive analysis of selective flocculation am fine hematite selected based on the combination of soluble starch and the characteristics of acrylamide was prepared soluble starch - grafting of acrylamide polymer flocculant. We can see through selective testing, the preparation of starch - acrylamide graft polymer of pure quartz and pure hematite were produced on the surface adsorption, through the measured absorbance and then converted to the concentration of ways we can see remnants of the graft material in the quartz very small amount of surface adsorption, while in hematite adsorption volumes. By hematite flocculation test we can see, with flocculants prepared by flocculation, its ability to better than selective flocculation modified maize starch and polyacrylamide.

Abstract: Carlin Trend gold ores are often refractory by conventional cyanid, for a number reasons:1) the gold is locked up within host sulfide minerals such as pyrite or arsenopyrite; 2) the ore contains carbonaceous compounds which are preg-robbing; 3) the gold is locked up in silicate minerals. An alternative technique called diagnostic leaching, originally developed by the Anglo American Research Laboratories in South Africa, has been used successfully to distinguish between a wide variety of different gold associations, including the proportion of preg-robbing gold in carbonaceous gold ores.

Abstract: The paper analyzed the basic physical and chemical features of metallurgical dust.This mud contains lots of useful elements including Fe,Zn and C etc.Combining with Borne dressing methods of gravity separation, magnetic separation or leaching and some molding technology, the metallurgical dust can be rationally utilized so that the comprehensive utilization of secondary resources can not only be realized, but environment be protected. Then good economic and social benefits were created.

Abstract: It was determined through a large amount of beneficiation test to adopt stage grinding-low intensity magnetic separation-high intensity magnetic separation-reverse flotation as the principle beneficiation flowsheet for a certain hematite in Hebei. The test results indicate that we can get iron concentrate with a grade of iron 65.19% and a recovery of iron 63.17% respectively at iron concentrate 21.90%, the primary grinding of 67.54%-200 mesh and secondary grinding of 97.70%-200 mesh.

Abstract: A novel wavelet transform — the least-square transform is proposed in the paper, which is used to extract weak fault signals from strong interference signals in coal mineral well. With the help of the least-square transform, a smooth fault signal curve can be got from the fault signal with high noise. Strong interference signals in the coal mineral well give a so serious problem on the work of general electric investigation that sometime process of observing useful fault signal cannot be finished. For extracting the weak effective fault signals from strong interferences signals in coal mineral well, original measured signals are decomposed by the least-square transform wavelet transform proposed in the paper, and the weak effective fault signals are extracted successfully. Experimental results show that the approach method is feasible and efficient.

Abstract: In the next 20 years, how many copper resources China has, when the peak demand peak comes, how great is the supply gap, and how to deal with that situation Scientific answer these questions is important premise to reasonably establish the national copper resources supply strategy, and guarantee the safety of Chinese copper resources. The next 20 years, even by low growth situation, China's copper demand will also be more than half of total of 20 century global copper consumption, the domestic copper resources supply capacity cannot satisfy the demand, external dependence will be maintained for a long time in 70% or so, which should be paid attention to, scientific deployed, and dealt with.

Abstract: High-efficiency flux was developed to lower the ash fusion temperature of coal LQ and reduce the addition content in coal gasification process. The effect of high-efficiency flux on the coal ash melting temperature and mineral transformation were studied by ash fusion temperature detector and XRD (X-ray diffractometer) respectively in reducing atmosphere. Compared with limestone flux, the high-efficiency flux can decrease the coal ash melting temperature effectively with half addition content. The ash flow temperature (FT) of coal LQ can be lowered to less than 1350°C with the addition of 3% high-efficiency flux ,while limestone flux need to add more than 8% to reach to this temperature. With the high-efficiency flux added, cordierite, anorthite and Mg-Fe-Al oxide were formed at high temperature, which is the main reason to sharply decrease the ash fusion temperature.

Abstract: This research investigated on reducing carcinogenic polycyclic aromatic hydrocarbons(PAHs),especially benzo[a]pyrene (BaP) in coal tar pitch by modifying with the two selected modifiers: Paraformaldehyde and Epoxy Resin. The reaction emphasis on the change of temperature, reaction time and the quantity of the modifiers. The results indicated that Paraformaldehyde and Epoxy Resin could decrease the PAHs content greatly. The BaP decreasing rate reached 75.86% and 53.45% respectively. And the BaP equivalency content of the pitch decreased from 2.94% to 1.41% and 1.47% respectively. The properties of the modified coal tar pitch, including soft point (SP), toluene insolubles (TI), quinoline insolubles (QI) have changed a lot.

Abstract: Three typical Chinese individual coals which existed remarkable difference on coal ash chemical composition and ash fusion temperature were selected to carry out coal blending experiments to study the coal gasification reaction at high temperature by means of using ternary-component blended coal technique and TGA-DTA method. According to ternary-component blended coal with a certain proportion, ash chemical composition and coal-char/CO2 gasification reactivity were analyzed by X-ray fluorescence (XRF) and thermogravimetric analysis-derivative thermogravimetric analysis (TGA-DTG), respectively. The results show that the ash chemical components change because ternary-component blended coals change the mineral composition, and hence, the gasification reactivity can be affected as well. Moreover, in accordance with reactivity index R, it indicates that the order of gasification reactivity of three individual coals and four blended coal options is coal x > option B > option A > option D > option C > coal z >coal y. Meanwhile, a new mathematical model called per unit ash alkali index B* was established by using the ash chemical component dates, which has a good corresponding relationship with R for four blending coal options. Utilizing ternary-component blended coal technique could improve the high-temperature coal ash gasification reaction.

Abstract: The Yining char samples were prepared in following conditions that raw coal particle size was in range 5-6mm and pyrolysis final temperature was 900oC, 1000oC and 1100oC, respectively, with a heating rate 20oC/min under atmospheric pressure. The gasification reactivity of chars was performed by thermogravimetric analysis (TGA) at 900oC in steam, CO2 and steam/CO2 mixture, respectively. The results show that the gasification reactivity of chars decreases with the increasing of pyrolysis final temperatures and there is synergistic effect between steam and CO2 during co-gasification that influences the char reactivity. The reason may be explained by char structure change, which FTIR showed that –CH3 and –O–CH3 decreased and even disappeared and XRD analysis suggested that the thickness of microcrystalline Lc, the values of microcrystalline diameter La and the aromatic of char fa became larger with increasing pyrolysis temperature.