Mining Products Safety Approval and Certification Center

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Mining Products Safety Approval and Certification Center

Beijing, China
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Shi Z.,China University of Mining and Technology | Shi Z.,Mining Products Safety Approval and Certification Center | Zhu Z.,China University of Mining and Technology
Wear | Year: 2017

The wear characteristics and related mechanisms of the middle plate of a coal conveyor chute were investigated. Multiple sets of wear tests were performed in order to simulate the range in working conditions of the super heavy-load scraper conveyor. Three compositions of mixed material (coal, gangue and water) were tested at different contact pressures and sliding speeds. The results indicate that the wear loss of the middle plate increases with the contact pressure and sliding speed with the same composition mixed material. In addition, the wear loss shows a decreasing trend with an increase in the mass ratio of water, coal and gangue at a specific contact pressure and sliding speed. Based on the substantial analysis of experimental data, interaction technique, modern tribology theory, and the appearance of the samples after the experiment, a statistical wear mechanism distribution diagram of the middle plate was constructed. This diagram is divided into three regions: a slight wear region, a moderate wear region and a severe wear region. The dominant wear mechanism was verified with the observed wear morphology of the middle plate after a given length of time. Therefore, this approach is proposed to be valid and practical. They provide a reliable theoretical basis and technical support for the design, use, and maintenance of the middle plate, the chute, and the entire scraper conveyor. © 2017 Elsevier B.V.


Wang A.,China University of Mining and Technology | Cheng X.,China University of Mining and Technology | Meng G.,China University of Mining and Technology | Wo L.,Mining Products Safety Approval and Certification Center | Pang Z.,China CAMC Engineering Co.
Advances in Mechanical Engineering | Year: 2016

The central groove is a key component of armored face conveyor. Failure of welded joints in the central groove often occurs in engineering. In this article, the welding procedure parameters were analyzed to the improve strength and toughness of the dissimilar steel weld joint in the central groove. First, four types of super-high wear-resistant steel and two types of high-strength welding wire were chosen as the welding materials. Carbon equivalent method, cold crack sensitivity index method, and maximum hardness of heat-affected zone test were applied to analyze their welding properties. Second, to improve their weldability, the proper preheating temperature was determined using Y-groove cracking test and mechanical property tests. Finally, a semi-automatic CO2 welding method was adopted, and a second mechanical property test was conducted to determine the proper welding wire. Results show that the chosen steels have poor weldability and cold cracking sensitivity. Preheating must be used to prevent cold cracking. When the preheating temperature is higher than 80°C, the cold crack rate can be controlled to under 20%, which can satisfy application requirements. Welding wire YMGR76 is appropriate. Using YMGR76, the preheating temperature drops to 120°C, and the strength and toughness of the weld joint are improved to 813 MPa and 112 KV2/J, respectively. This study provides a welding procedure to improve the reliability of the central groove. © 2016 Author (s).


Songtao W.,China University of Mining and Technology | Shuai Y.,China University of Mining and Technology | Zhiyang X.,Mining Products Safety Approval and Certification Center | Yu Y.,Yongmei company
Electronic Journal of Geotechnical Engineering | Year: 2014

The dynamic response mechanism of the rock fragmentation and its influential factors by TBM disc cutter are studied in this paper. Firstly, a dynamic response model is established based on the fracture mechanics and finite element theory. Secondly, a fragmentation rule is founded according to the dynamic response model, and then numerical simulations for dynamic response of rock are carried out. Lastly, cutting experiments are carried out in order to check the numerical simulation. The simulation and experiment results for different rocks show that the rock cutting depth and the crushing region decrease with increase of the rock compressive strength. The simulation and experiment results for different loads show that the fragmentation scale is proportional to the cutting force for the same rock. © 2015 ejge.


Li B.,China University of Mining and Technology | Li B.,Mining Products Safety Approval and Certification Center | Wang Q.,China University of Mining and Technology | Zhang Y.,Mining Products Safety Approval and Certification Center | And 2 more authors.
International Journal of Electrochemical Science | Year: 2013

Single-crystalline nanorods of monoclinic Li2MnO3 with about 200 nm in width and around 8 μm in length have been synthesized via a template-sintered reaction using γ-MnOOH nanorods as a template. Nickel-modified and Zirconium-modified Li2MnO3 cathode are also obtained respectively. Nickel-modified Li2MnO3 cathode (0.5Li2MnO3.0.5LiMn0.5Ni0.5O2) delivers the highest initial discharge capacity of 497 mAh/g at 0.1 C in the voltage range of 2.0-4.6 V. Although without distinct higher discharge capacity, Zirconium-modified Li2MnO3 cathode (0.5Li2MnO3.0.5LiMn0.5Zr0.5O2) improves cycle stability to a certain extent. Voltage plateaus of cathode materials can be apparently observed after modified by Nickel and Zirconium and electrochemical performance is enhanced. © 2013 by ESG.


He K.,China University of Mining and Technology | He K.,Mining Products Safety Approval and Certification Center | Zhang Y.-L.,Taiyuan University of Technology | Shi J.-W.,China University of Mining and Technology | Wang F.-Y.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2016

The complex macromolecular matrix of coal was divided into the elements of C, O, H, S and N, which were involved in the oxidation reaction. Based on the changes of element contents during coal oxidation process at low temperature, the three kinetic models, including pseudo-first-order kinetics model, Coats and Redfern's model, and Freeman and Carroll's model, were introduced to investigate the kinetic characteristics of coal oxidation at low temperature. Kinetic study reveals that the evolutions of these elements during coal oxidation at low temperature follow pseudo-first order kinetics and Coats and Redfern's model. The activation energies for these elements evolution in the oxidation process by using the pseudo-first order kinetics have been found to be almost similar to those calculated by applying the Coats and Redfern's equation. The reaction rates computed by the pseudo-first order kinetics are very low and have been found to be 10-5-10-6, suggesting a very low rate of successful collisions for the formation of activated complex. A kinetic compensation effect between the activation energy and exponential facto was also observed for the evolutions of these elements. © 2016, Editorial Office of Journal of China Coal Society. All right reserved.


Li B.,Mining Products Safety Approval and Certification Center | Dang Z.,Mining Products Safety Approval and Certification Center | Zhang Y.,Mining Products Safety Approval and Certification Center | Song Z.,Mining Products Safety Approval and Certification Center
International Journal of Electrochemical Science | Year: 2014

The present work describes using γ-MnOOH nanorods as a self-template to form Li-Mn-O compounds via hydrothermal process and state reaction, and a key finding in phase transition from cubic to monoclinic with Li content increasing. As the cathode material for lithium batteries, the electrochemical performances of as-prepared materials are investigated. © 2014 The Authors.

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