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1、外文原文Measurement of magnetic susceptibility in titanium minerals processingInstitution The University of Queensland Publication date 2004 Supervisor(s) Dr. Peter HolthamDr Toni Kojovic Magnetic separation is routinely used in the processing of titanium minerals, and the efficiency of these operations
2、 can be determined by measuring the magnetic properties of the process streams. The valuable components in the feed to a titanium minerals plant have specific magnetic susceptibilities ranging from -10-9 m3kg-1(zircon) to 10-6 m3kg-1 (ilmenite). However, in an industrial environment, in which the mi
3、neral temperature may range from 20 to 120C, it is difficult to measure susceptibilities lower than about 10-7 m3kg-1. Hence laboratory testing of spot samples from magnetic separators is currently required to obtain accurate performance data. This is an inherently slow process and where feed grades
4、 are variable, optimum performance of separators is generally not achieved. This thesis describes the development of an inductance-based instrument for measuring down to low levels of magnetic susceptibility online in harsh plant environments. The major difficulties in developing this device were te
5、mperature induced changes in the resistance/ capacitance of the inductance coil and phase stability of the inductance coil excitation current. Coil temperature problems were solved by using a physical small coil in batch operation. Phase stability was overcome by designing a phase extraction system
6、that used the coil excitation phase information as part of the phase extraction algorithm. Investigations were made into calibration and measurement error of the instrument. Calibration at low levels of magnetic susceptibility was performed using a range of chemical salts. For higher susceptibilitie
7、s no well defined calibration standards were found and a method to measure high levels of susceptibility was formulated. The method relies on diluting the highly magnetic material with salt to prevent magnetic interaction between particles. It was found that the resolution of the electronics was the
8、 most significant error and the homogeneity of the sample the least significant. Plant samples were tested and the device was able to determine the zircon content in a zircon magnetics circuit, determine the TiO2 content in the non-mag stream of a magnetic circuit, determine the iron content in the
9、mag stream of a magnetic circuit and determine the metallic iron content of reduced ilmenite. The device has also been used in a system to determine the mass distribution of the magnetic properties of a titanium mineral sample in less that 1 minute. Previously, the distribution was determined using
10、a laboratory scale magnetic separator (e.g. an Ore Sorters Permroll), with it taking approximately 40 minutes to process each sample. The system is best described as an hourglass with mineral flowing from a hopper through a small inductance coil. The impedance of the coil is proportional to the mean
11、 magnetic susceptibility of the number of particles within the coil (i.e. each measurement is the mean magnetic susceptibility of a fixed size group of particles). An algorithm has been developed to determine the percentage of the feed material at each level of magnetic susceptibility. Hence the res
12、ults are identical to those determined using a laboratory magnetic separation. Accuracy of the device has been proven by simulation and by testing of plant samples using the new system and comparing the results with measurements made using a Permroll separator. The thesis also presents recommendatio
13、ns for future work and future potential applications of magnetic susceptibility measurement to mass flow of titanium minerals, measurement of moisture content and jigging operations.According to early literature reports, VCl3 reacts quickly with alcohols to give vanadium(IV)/(V) alkoxides leaving fr
14、ee chloride in solution.Moreover, vanadium(III) is highly oxophilic and produces stable vanadyl complexes in the presence of traces of moisture or O2. Strict dioxygen and moisture exclusion conditions are needed to avoid oxidation and hydrolysis involving the metal. The formation of the desired VCl2
15、Ti2(OPri)9 by the route described in this work is dependent on the preservation of the metal oxidation state and cannot be accomplished if vanadyl species are formed in the reaction mixture. Simple Schlenk line conditions give reproducible results for this preparation, but do not appear to be adequa
16、te to give the heterometallic product. Product 1 has been used as a precursor to nanosized particles of TiO2 by a sol-gel process. Details of these preparations will be described elsewhere.中文译文钛矿物加工磁化率测量机构 昆士兰大学出版日期 2004监事 彼得Holtham博士 托尼Kojovic博士磁选钛矿物加工中经常使用的，可以通过测量过程流的磁学性质决定的，这些行动的效率。钛矿物植物饲料中的有价值的成分，具有特定的范围从10-9 m3kg-1（锆石）到10-6 m3kg-1（钛铁矿）的磁化率。然而，在工业环境中，其中矿产温度范围可从20至120C，它是很难衡量的敏感性低于10-7 m3kg
