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By E. Onal, C. Craddock, A. Chapman, M. R. Endsley

ABSTRACT Mining equipment operators must interpret and respond to complex information delivered by technology-centric rather than user-centric systems. The ability to achieve high situation awareness (SA) in the face of this data overload is a key challenge to effective decision-making and information exploitation. Incidents attributed to human error that compromise safety and result in loss of revenue, or even life, are often the result of system designs that overload human cognitive capabilities. This paper defines SA as it relates to the operation of mining equipment and describes the design and preliminary evaluation of a new electric shovel operator user interfa

Jan 1, 2013

By Mei Song, Qingyu Deng, Xuewei Lv, Lu Liu, Chenguang Bai, Meilong Hu

"The carbochlorination of several silica materials was carried out in the temperature range from 900 °C to 1200 °C. In this study, silica oxides and gaseous chlorine with carbon as reductant were used. The optimal carbon silica mole ratio in different temperature was calculated by Factsage software and the results showed that the optimal values are 1.2, 1.4, 1.6, 1.8 at 900 °C, 1000 °C, 1100 °C, 1200 °C, respectively. According to the experiments, the chlorination ratios of several silica materials were increased with temperature increasing. In the same temperature, the chlorination ratio of diatomite is the maximum and the chlorination ratio reaches 79%% when C/SiO2 reaches 3 at 1100 °C.1, IntroductionPolycrystalline silicon is the main material to manufacture the silicon polished section, solar battery[1] and high purity silicon wafers[2], also which is the most basic function material of semi-conductor industry, electronic information industry and solar photovoltaic battery industry[3]. The conventional manufacturing process of polycrystalline silicon would be divided into three parts: the improved Siemens method, which was introduced and became the main process to produce the polysilicon products in China. Silane method and fluidized bed method. Silicon tetrachloride and chlorosilans have been employed as by-products in several fields like electronic, telecounications and metallurgy[4-6]• At present, the main applications of silicon tetrachloride include production of trichlorosilane by catalytic hydrogenation, synthesis of fumed silica and ethyl orthosilicate, production of optical fiber grade silicon tetrachloride.The conventional routes for the silicon tetrachloride production have been reported, including the direct chlorination and the chlorination process of ferrosilicon, abandon catalyst and silica[7]."

Jan 1, 2013

By B. Papilon

Dynamic pressures during blasting can affect performances of both electronic and non-electronic detonators. Boreholes can develop tremendous amount of pressures during blasting. The effect of such elevated pressure especially during electronic delay countdown is probably more acute in electronic detonators. Measuring the pressures during blasting can aid to understand the relationship between magnitude of the pressure developed and the multitude of blasting conditions.

Jan 1, 2013

By Alan Christopherson

Nearshore construction projects often require installation of steel piles and specific methodologies of installing piles may adversely affect nearby species of concern. Water is an uncompressible medium which allows for easy transmission of energy through the water column. Energy transmission through water depends on the following factors for pile driving: 1) direct contact of the pile and the water; 2) the depth of the water column; 3) the size of the pile; 4) type of hammer; and 5) the energy of the hammer. Seasonal restrictions are usually the best practicable alternative for reducing habitat impacts when pile driving activities may adversely affect the species of concern. When seasonal restrictions are not practical other options need to be evaluated, including mitigation and noise attenuation devices. The broad array of mitigation options will not be discussed as part of this presentation but instead will focus on noise attenuation technologies. Dewatered cofferdams can be effective noise attenuators as they eliminate direct contact of the pile with water while driving. Also, introduction of a compressible medium, like air, near the energy source can provide sound energy attenuation. An unconfined bubble curtain is relatively inexpensive but is not effective in tidal marine projects or rivers and may have unacceptable secondary effects. Secondary effects must be evaluated as these can increase exponentially for larger projects. Secondary effects to the environment include air quality degradation from air compressor use, transportation costs for fuel and equipment, and the potential for injecting oily compressed air into the water column. The confined bubble curtain works well in nearly all environments. It usually is more expensive initially, relative to an unconfined air curtain, but there is less potential for harmful secondary effects. Generally, seasonal restrictions will be adequate to protect species of concern. However, there are conditions in which mitigation or one of the sound attenuation options should be utilized. Site specific factors, including the amount of energy being imparted into the environment, sensitivity of the species of concern, current, accessibility, length of time needed to complete the project, and the cost of the sound attenuation, should be factored into the permit evaluation.

Jan 1, 2013

By Mitchell L. Spencer, Viswanathan Panchanathan

"Bonded magnets are important category in permanent magnets. They are made by one of the following processes: compression bonding, injection molding, extrusion, calendering. An overview of the various bonded magnet processes and properties of products made with different magnet materials along with their applications are discussed. The main emphasis will be on the use of bonded NdFeB and ferrite magnets.IntroductionBonded magnets are a major growth area in permanent magnets. Bonded magnets are made by any one of the following processes: Compression bonding; Injection Molding; Extrusion and Calendering [1,2]. Compression and injection molded magnets are rigid magnets. Materials used in calendering process produce flexible magnets. Only the extrusion process makes both rigid and flexible magnets. The binders used for the bonded magnets vary depending on the processes. Thermoset, thermo-plastic and elastomeric binders are respectively used in compression, injection and the calendering process. Extrusion molding uses elastomers or thermo-plastic materials. The most co=on magnetic materials, Ferrite, SmCo, Alnico and NdFeB can be used in any of the above processes either alone or in combination as hybrid magnets. Another material that has been developed for co=ercial application is SmFeN. Making the material has been challenging and it is being used in niche market applications in limited quantitiesIn the extrusion process, a highly loaded compound is used to produce strip or sheet and is continuously extruded through a die. In calendering the granulated compound is rolled to produce a continuous wide sheet. In the compression bonding process a uniaxial pressing force is used. These magnets have higher loading compared to injection molded magnets. In injection molding the material is forced into a mold cavity and has lower loading compared to compression molded magnets [2,3]. Most of the flexible magnets are made using extrusion and calendering processes and the most co=on magnet material is inexpensive ferrite. Flexible magnets have been made using rare earth materials, but on a very limited basis.The major advantages of magnets processed by extrusion and calendering are as follows: inexpensive tooling, automation; practically any 2D geometry; fast production rates; no chipping or breaking; a wide range of properties; on-line magnetization; easy to convert (e.g. cut, punch or shape).Compression bonded magnets are inexpensive to manufacture. They have higher magnetic properties compared to injection molded magnets; however lower than their sintered counterparts. The magnet shape is restricted to simple geometries and they require careful handling. Their isotropic nature allows complex magnetizing patterns."

Jan 1, 2013

By Mark Jolly, Nasim Soleimanian

"During the last 20 years CFD (Computational Fluid Dynamics) has been used as a tool to aid furnace designers and manufacturers to improve energy efficiency and effectiveness of glass furnaces. However as the models are maturing the effect of feeding equipment used to push the raw material into the furnace has not been included in the process models. This paper investigates the effects of batch pattern in the melt space caused by charging equipment on the energy efficiency of the furnace focusing on the melting zone. A simple batch patterns sensitivity study has been performed using purpose built software (Glass Furnace Model-GFM). It is concluded that in order to further reduce the energy consumption of the furnace it is necessary to model the batch charging process in more detail to find more opportunities for improvement.Introduction Glass manufacturing is a conservative industry which applies to all the four major segments (float glass, container glass, fiberglass, and specialty glasses). Risks due to the high capital investment, very long service life of the furnaces, and the demand for high performance and quality from the outset translates into evolutionary progress rather than revolutionary. The main problem facing glass manufacturers are the financial cost of manufacture, its impact on the environment, and mounting pressure imposed by the authorities for greener manufacturing and reduction in emissions.The main energy intensive activities involved in continuous glass manufacturing are: the need for high temperature to create and maintain the viscous flow, homogenisation of glass melt (melt residence time), and maintaining the two to achieve continuous output of glass at the right quality. The high temperature and long duration of homogenisation has resulted in the design oflarge furnaces, which have high energy consumption, low specific performance, and high C02 emissions. As an example in the container glass sector the most efficient furnace has a specific primary energy consumption of 3.8 GJ /tonne of glass at a level of 50% cullet in the batch. Even very small improvements in efficiency by optimising operation would have a high impact [1-14]. Given the conservative nature of the industry and the costs involved in experimental data gathering, CFD modeling of the process has been used extensively during last two decades to not only improve our understanding of the process but also as a tool in predicting possible optimisation windows, e.g. Glass Furnace Model ( GFM), a commercially available piece of software that has been developed to optimise furnace operation."

Jan 1, 2013

By Shadia J. Ikhmayies

"Cadmium telluride (CdTe) is a very interesting material that has many applications. Thin films of p-type CdTe can be used as the absorber layer in the heterojunction CdS/CdTe thin film solar cells in which n-type cadmium sulfide (CdS) works as the window layer. A review of the photoluminescence (PL) spectra ofp-type CdTe thin films prepared by different techniques was performed. The presence of defects and impurities such as oxygen and chlorine influence the PL spectrum. Copper and other dopants change the PL spectra and enhance the defects band. Chemical-heat treatment especially with CdCh is known to improve the quality of CdTe thin films because it decreases the Cd vacancies and quenches deep traps, so it enhances the PL signal. A discussion of chemical-heat treatment especially with CdCh, the effect of the ambient atmosphere, and that of the measuring temperature is performed.IntroductionCadmium telluride (CdTe) is a II-VI compound semiconductor that has a cubic zincblende (sphalerite) structure with a lattice constant of 0 A4~11]. Other than all of II -VI semiconductors, CdTe can be made both n- and p-type. But due to self compensation it is not easy to get p-type CdTe films [2]. Polycrystalline CdTe thin films are interesting because they have a lot of applications. Most of the problems associated with the use of these films are attributed to inhomogeneity, self-compensation, and the difficulty of forming a stable and lowresistivity ohmic contact [3]. CdTe technology has been established for a large number of applications, including solar cells, optical and nuclear detectors, and thermal- and radiationimaging devices [3]. At present, the highest demonstrated conversion efficiency for a CdTe based heterojunction (ID), with CdS as a window layer, is 16.5% [4, 5]. CdTe thin films can be prepared by different experimental techniques, such as thermal evaporation [l], electrochemical deposition (ED) [3], close-spaced sublimation (CSS) [3, 4, 6], physical vapor deposition (PVD) [3], chemical molecular beam deposition (CMBD) [7], and close space vapor transport (CSVT) [8].The objective of this paper is to make a review of the photoluminescence (PL) spectra ofp-type CdTe thin films prepared by different techniques and discuss the factors that influence the PL spectra. The composition of the film is very interesting in determining its PL spectrum. Different kinds of defects, impurities and dopants have their finger prints in the PL spectrum. Deposition techniques and deposition parameters such as the deposition temperature and ambient atmosphere also have their influence. Heat and chemical treatments which are known to improve crystallization and reduce the defects change the PL spectrum."

Jan 1, 2013

By Manqiu Xu

"Ore grades are decreasing and ore deposits are becoming more complex. In order to make a sound economical decision about a mining project, metallurgical testwork must be carried out. A few large “representative” samples cannot represent the metallurgy of a large ore body and a large number of samples reflecting variation in ore head grades and in mineralization types must be obtained for proper metallurgical studies, including flowsheet development for a greenfield project. A relationship can be established between the recovery of valuable minerals and ore grade for each mineralization type. This relationship can be used to establish a correlation between values recoverable and values contained in the ore body that can include multiple pay metals. With this information, a sound economical decision can be made about the viability of a large mining development project.INTRODUCTIONThe demand for minerals today is historically high as many countries are being rapidly industrialized. The supply for these minerals is not necessarily running short. However, it is widely accepted that the world today is running short of the easy to mine and easy to process ore deposits. As ore grade is decreasing and ore mineralogy is becoming more complex, metallurgical testing must be fully conducted in order to make a sound economical decision about a mining project. For a high-grade and high-quality deposit, it is hard not to make a good profit even with low metal prices. For a low-grade and hard to process deposit, the profit margin is much lower and is dependent on the throughput and the recovery of valuable minerals. The recovery of valuable minerals is a function of ore grade and mineralogy and it must be experimentally determined for a given processing option.At Vale Base Metals Technology Development, metallurgical testing for an existing operation or brownfield project is termed as Ore Evaluation, while metallurgical testing for a greenfield project is termed as Flowsheet Development (Xu, 2011). In the past, metallurgical testing involved a few large composite samples for lab and pilot plant testwork. As ore deposit becomes less homogeneous and more variable, a few large composite samples cannot represent the metallurgy of a large ore body. In addition, useful information about the deposit such as zones of “impurities” or floatable rock minerals would not be obtained. Different processing strategies could have been developed if the locations and sizes of these zones were known in advance. For proper metallurgical studies, a large number of samples reflecting variation in ore head grades and in ore mineralization types must be used. A relationship can be established between the recovery of valuable minerals and ore grade for each mineralization type. This relationship can be used to estimate values recoverable in the ore body that can include multiple pay metals. Ultimately, the recovery verses ore grade relationship will be used in business decision-making."

Jan 1, 2013

By Joshua Hoffman

The recruitment and retention of future talent into the explosives industry is becoming increasingly important. Student chapters help with this effort but what are they doing and are there things they could learn from each other? This paper discusses the University of Kentucky Student Chapter's efforts to grow membership, retain its recruits, and integrate them into the explosives industry. Several social and professional events during which the students are able to meet and network with members of their future industry are introduced. The special relationship that has been fostered between the University of Kentucky and Missouri University of Science and Technology is discussed. Professional development initiatives which are critical for a student to become vested in the industry are shared in this paper. These opportunities which range from internships to research positions allow a person to get a better understanding of the explosives industry and find the niche that best suits them. Many of the student chapters are closely connected with engineering programs. While this makes sense and both entities benefit from these arrangements there is a trend of job placement primarily in the engineering industry. By providing these students with the chance to learn more about the explosives industry and get hands on experience more of these future engineers and professionals can be retained after their graduation.

Jan 1, 2013

By Lin Yang, Minjun Tang, Shuishi Liu, Jianfeng Zhou, Linjiang Qing, Xiaolei Song, Yufeng Guo, Tao Jiang

"The dynamics of oolitic hematite magnetic roasting was studied. The results show that oolitic hematite magnetic roasting was controlled by the internal diffusion, and the diffusion coefficient was 9.018x10-7 m2·s-1when the oolitic hematite was roasted at 650°C. Magnetic susceptibility improves when temperature increases and roasted time prolonges under the condition of roasting at 650°Cfor 50min, with the magnetic susceptibility is 39.88%. CaF2 and Na2C03 can significantly improve the magnetic susceptibility at the same roasting condition, and the magnetic susceptibility was 63.35% and 57.99% respectively, thus the reduction of oolimic hematite was promoted.IntroductionWith the continual depletion of free-milling iron ores and its rising price, developing the abundant resources of oolitic hematite has become one of the main research areas. The oolitic hematite accounts for 10% of China's iron ore reserve, and it also accounts for 30% of red ore reserve in China [1]. In order to exploit the oolitic hematite, there are many beneficiation research methods, including fine grinding/selective flocculation/high intensity magnetic separation or flotation, high-gradient magnetic separation, low intensity magnetic separation/high intensity magnetic separation/reverse flotation, chloridizing roasting/acid pickling, magnetic roasting/leaching process etc [2]. However, the oolitic hematite is easy to slim and the valuable mineral is covered by the slim, because of the tiny granule of value mineral, then the ooides are formed due to the state of layer morphology formed by iron ore and ganaue minerals [3, 4]. Fairly good separation indexes were hard to be obtained by traditional separation due to its structural features, so the magnetic property of the iron minerals will be changed with the use of the magnetic roasting [5, 6], which result in hematite variably altered to magnetite and simplified technological process so that a good separation indexes will be obtained by using the low intensity magnetic separation. Therefore, in order to provide theoretical direction of how to use the oolitic hematite effectively through the magnetic roasting, the oolitic hematite of GuiZhou province was studied, which emphasized on researching the dynamics of oolitic hematite magnetic roasting."

Jan 1, 2013

By Zhucheng Huang, Lingyun Yi, Bin Chai, Tao Jiang

"A high iron content manganese ore was reduced at 900~1200°C and followed by a magnetic separation process. SEM and EDS analyzes were employed to examine the transformation of microstructure and phase in reduced sample and the mechanism was revealed. Results showed that elements enriched during reduction. Iron existed in the metal iron phase and most of oxygen formed compound with manganese. Consequently a clear distinguish between iron phase and manganese minerals formed, which was beneficial to the separation of iron and manganese. But the iron phase can not be monomer dissociation in grinding process and manganese compounds turned into magnetic product as package and mechanic inclusion due to the isomorphism of iron and manganese and the small particle size. And MnO could be found partially in iron phase, which hindered the further separation of manganese and iron.IntroductionManganese is widely used in industry. The amount of manganese used in steel industry is very huge and 90% manganese is used in steel industry. Manganese ore resources are rich in China, yet with fewer rich ore but more low-grade ore which accounts for 93.6% and fine refractory ore. The constitution of the ore is very complex and more than 73% of all the manganese ore contains iron[l,2]. With the increasing of consumption of steel, the demand for manganese is becoming larger and larger and the imported ore accounts for more than 50%. Therefore, how to use the manganese ore efficiently has very significant meaning. The main method is manganese residual, which is simple and stable. However, the development of the method is limited by the quality of manganese ore, the huge amount of manganese residual, the technology of blast furnace process and economics[3,4]. Chemical benefication which may pollute environment and is difficult to recover iron is still being researched[5,6]. The paper investigated the process in which anthracite coal was the reducing agent for coal-based direct reduction and magnetic separation of the ore, and SEM with EDS measurements were employed to examine the transformation of phase in reduced sample and the mechanism was revealed[7,8]."

Jan 1, 2013

By J. E. Danoczi

ABSTRACT A diamond processing plant is being designed for the Star–Orion South diamond project in central Saskatchewan. Key to the plant is diamond liberation, which occurs in the comminution section and is the process of breaking up kimberlite rock as gently as possible to minimize diamond damage, particularly in larger, high-value diamonds. Kimberlite from the crater area of a volcanic pipe is generally softer than kimberlite from the diatreme zone. Softer kimberlite, comprising the majority of Star– Orion South deposits, can be readily broken up using abrasion and attrition by autogenous grinding mills, the preferred comminution method for minimizing diamond damage.

Jan 1, 2013

By Jun Li, Lin Chen, Tian-zu Yang, Wei-feng Liu, Wan-da Bin

"The Chinese bismuth production accounts for more than 80% all over the world in 2011. The main raw materials of bismuth smelting are bismuth concentrate and by-products of Cu or Pb smelting process. Many traditional methods of bismuth smelting in china was reviewed in this paper, such as reverberating furnace smelting, blast furnace smelting, fire-refining, ferric chloride leaching-hydrolysis, slurry electrolysis, and so on. But all the traditional pyrometallurgy or hydrometallurgy process have such shortages of low recovery, poor environment, and high cost. Therefore new technologies are introduced into the smelting process of bismuth concentrate, such as low-temperature alkaline smelting and side-blown bath smelting with oxygen-enrichment. These technologies have got great progress on energy saving, emission reduction, and friendly environment. Finally the development direction of new technology on bismuth smelting was prospected.IntroductionAs a green metal, bismuth has a wider applications, just extending from the traditional medicine, metallurgical-chemical engineering, low-melting alloys, solders, catalyst, and electronics to cosmetics, flame retardant, storage battery, semiconductor, supper conductor and nuclear energy etc[1,2,3,4,5,6,7]. This will increase the production of bismuth and promote the development and progress of bismuth smelting technology. At present, The major bismuth-product countries are China, Mexico, Peru, KZ, Bolivia and Canada etc, and China are dominating. A survey from the USGS[8] showed that Chinese bismuth production were 12,500 tonnes and got 80% of the world's in 2011. Thus the technology of Chinese bismuth smelting have a great representativeness."

Jan 1, 2013

By J. Paraszczak

ABSTRACT Diesel-powered loaders are a pillar of modern underground metal mining. As these mines are getting deeper and hotter and the emission regulations stricter, ventilation costs are soaring, affecting production cost. Also, the cost of diesel fuel is expected to rise. These may make the use of diesel engines more problematic. Electric load-haul-dump machines (LHDs) are an interesting alternative. This paper compares features and performance of diesel and electric, cable-powered LHDs. It overviews equipment offerings, and compares, analyzes and discusses technical parameters, operational problems and cost issues. The paper gives some conclusions about electric LHD applicability and performance, indicates possible applications, and suggests further research work.

Jan 1, 2013

By W. B. Lambert

A common decision in openpit mining is to determine the extraction sequence of notional three-dimensional production blocks so as to maximize the net present value of the extracted orebody, while adhering to precedence and operational resource constraints. This openpit block sequencing (OPBS) problem is commonly formulated as an integer program, with binary variables representing if and when each block is extracted. In practical applications, the number of blocks can be large and the time horizon can be long; therefore, instances of this problem can be difficult to solve using the exact approach of optimization. The problem is even more challenging to solve when it includes explicit minimum operational resource constraints. Our maximum value feasible pit (MVFP) algorithm generates an initial integer feasible solution for OPBS problems, in which minimum operational resource constraints are strictly enforced. As an exact approach, we present a Tailored Lagrangian Relaxation (TLR), in which the selection of constraints to dualize is guided by information provided by the MVFP algorithm. We present results and graphics to demonstrate the utility of our techniques for instances containing up to 25,000 blocks and 10 time periods.

Jan 1, 2013

By Michael Casson

With the mining industry changing rapidly due to mergers, acquisitions and fluctuating market pricing, today?s market for coal, minerals, ores and aggregates demands electrical apparatus that perform every time with maximum efficiency and with consideration for personnel safety. This is especially true in existing mining operations where every payload counts. Draglines are the workhorses of surface mining operations, and reliable and efficient operation is absolutely critical to success. However, the inherent disadvantages of using dc motors and motor-generator (MG) sets can significantly impact productivity and return on investment (ROI).

Jan 1, 2013

By Todd Burchett

Mining engineers spend countless hours and resources when designing a new underground coal mine. Their primary objective is to design the safest and most efficient operating mine with regards to coal production. A key variable often overlooked in this design stage is the slope conveyor. Typically, a slope conveyor is expected to operate with a 98-percent or higher availability. However, too often little effort is put forth by the mining engineer to optimize its design. Coal companies will rely on engineering, procurement, construction and management (EPCM) companies for the preliminary design, because the slope conveyor will be considered part of the surface material handling processes. This preliminary design will be used when soliciting quotations for the slope conveyor. Unfortunately, EPCMs may not have enough expertise with conveyors to optimize the design. This expertise is available with an original equipment manufacture (OEM) of conveyors, which ultimately may be responsible for supplying the slope conveyor. Each OEM will provide a bid package that represents what it considers to be the optimal design.

Jan 1, 2013

By San-chuan Tang, Wen Chen, Shun-ming Ning, Kan-ping Yu, Qiang Zhao, Xue-yong Xing

"A new type of desilication agent (PA-2) was selected by experiment based on the analysis of the characters of silica gel, and the influence of desilication type, desilication dosage, pH value, temperature and aging time on the desilicating effect was studied. The test results showed that on the conditions that pH was 2.0, temperature was 20""C, aging time was12 hours and the dosage of desilication agent was 0.23%, the desilication rate was higher than 93% in solution.IntroductionVanadium is an important strategic resources, which applies to steel industry and petrochemical industry. The main materials for vanadium product are steelmaking vanadium slag, stone coal and containing vanadium waste catalyst, etc. And stone coal is a low-grade carbonaceous silicified vanadium resource, which is unique material for vanadium extraction in China. Meanwhile, our stone coal reserves is No.l throughout the world.The silica acid solution containing vanadium is produced by acid leaching of raw stone coal or its roasted ore. The silica content of this solution is mostly high, besides, when pH is higher than 2 , the solution is unstable. Furthermore, it is very easy to generate gel substance with the increasing of pH value and standing time. 'Ibis silica gel is composed of colloidal particles with the size in 0.001 - 0.1 um. As a result, it is very hard even impossible for the following operation of solution."

Jan 1, 2013

By Norman Paley, Finn Ouchterlony

Detailed fragmentation data for different blast delay timing tests at the Red Dog mine in Alaska are analyzed. This work is a continuation of previous work in which the crusher output was found to be better described by the three-parameter Swebrec function than by the Rosin-Rammler function. For a crusher model, the x50 variable sufficed to describe changing crusher input while b and xmax could be considered fixed. For the crusher output from aggregated stockpile rock, as measured by digital image analysis using Split-Online, the constancy of b was not as apparent. In this paper detailed stockpile data, single Split data series, and sieved belt cuts of crusher product are analyzed using the Swebrec and truncated Rosin-Rammler functions. The variability of b is confirmed. By using specific fraction passing sizes a shortcut is presented that removes the need to do curve fitting to determine the three Swebrec function parameters.

Jan 1, 2013

By Jian Li, Guo Chen, Bingguo Liu, Hongying Xia, Jinhui Peng, Libo Zhang

"Decomposition of ammonium tetramolybdate to prepare Mo03 using silicon carbide crucible in microwave fields was investigated. The results were analyzed Using TG-DTG and X-ray diffraction. Meanwhile, the effects of heating rat, material thickness, socking time, socking temperature on the structure of preparing Mo03 were studied. TG-DTG curves show that the decomposition process of ammonium tetramolybdate is only one stage, in the temperature range 300-350°C, whose begin to decompose when temperature increases beyond 300°C. The molybdenum trioxide was prepared by thermal decomposition. The quality ofMo03 was not affected under the heating rat is 12°C/min. It was beneficial for decomposition ratio with the lower material thickness, longer soaking time, and higher soaking temperature. XRD curves showed that it is viable method for preparation of Mo03 by decomposition from ammonium tetramolybdate in microwave fields.IntroductionMolybdenum is widely used in national defense, aviation, industrial and agricultural production as rare refractory metal. Molybdenum trioxide is vital raw materials for the process of preparation of molybdenum. The traditional production technology of molybdenum oxide is that ammonium tetramolybdate is calcined in rotary kiln or 4-tube furnace [J,2J. But the longer production time, the higher production cost, the lower furnace thermal efficiency, and bigger the energy consumption, especially the powder is easy to leak, the working environment is poor by using rotary kiln [ 3 l _ The particle of molybdenum oxide is non-uniform by using 4-tube furnace because of the uneven temperature of every tube and the poor exhaust of boat bottom [4l _ However microwave heating is quick and uniformity, it is a meaningful research that the microwave is used in the process of calcining ammonium tetramolybdate."

Jan 1, 2013