| Vein quartz is one of nature's most common siliceous mineral raw materials,thermal SiO2 solution when the rock cooled underground magma formation,SiO2content is generally higher than 99%,and it's easy to be processed into SiO2 content above 99.9%purity quartz sand.Because of its good temperature resistance,low thermal expansion,excellent chemical stability,unique optical property and other characteristics,high-purity quartz is an important raw material to manufacture monocrystalline silicon,polycrystalline silicon and other high-performance materials,and it's widely used in many fields.Actively explore quartz mineral purification technology,improve the quality of quartz processing products,realize the batch of industrialization,to promote the development of new energy and other high-tech industry have a positive impact.This thesis utilized sichuan and other region vein quartz as the research object,studied the relationship between the different raw materials and processing quality of high-purity quartz,the relationship between the calcination temperature and high-purity quartz processing quality,reagents and container affected the processing of containers of high-purity quartz,finally carried out the processing of 4N8 standard grade high purity quartz applied experimental optimization process by vein quartz.Then using inductively coupled plasma atomic emission spectroscopy?ICP-OES?made chemical composition analysis for experiment samples,using polarized light microscopy and XRD made structural and phase analysis.Using our research group published about the optimization of acid formula processed 4N high purity quartz,selected the ore which fit to continue processing from 13mines in different region,VQ02,VQ03,VQ04,VQ09,high temperature treatment these four ores,analysis the influence of the quality of high purity quartz processing from calcination temperature and experimental water,reagent and container,under laboratory conditions,SiO2 content can meet the qualification of high-purity quartz high-end product standard,and carry out the processing of 4N8standard grade high purity quartz applied experimental optimization process by vein quartz,processing the samples meet the U.S.unimin IOTA-STD requirements.The research results obtained in this paper and the experiment progress is as follows:1.The relationship between different veins quartz and high purity quartz processing qualityAfter processing,the content of each individual impurity element mines were decreased,the corresponding amount of impurities is reduced.When choosing to do further processing,the principle are cost savings and equipment resources,then choose the ore containing fewer impurities in these vein quartz,so that priority should be given aluminum,alkali metal,alkaline earth metal content of the ore less.Taking all these factors,chose VQ02,VQ03,VQ04,VQ09 from these 13 shortlisted.2.The relationship calcination temperature and high-purity quartz purification processing quality?1?VQ04 can achieve the level of standard grade high purity quartz through high-temperature calcination,the optimum calcination temperature is 1400?,holding1h.VQ04 mine XRD illustrated,when carrying out high-temperature calcination,the temperature exceeds 1400?,the crystal inside occurs crystal transformation,the quartz transformed into cristobalite,the impurities would promoted the transition;?2?VQ02 ore cannot be used for the further purification process through high-temperature calcination.VQ03,VQ09,have reached at 1000?and 650?calcination and water quenching,for cost savings and other issues,VQ03,VQ09 are no need to further processing through high-temperature calcination.3.The influence of reagent and container to the purification processing effect of high-purity quartz?1?Distilled water and Wahaha purified water used in the experiment,and the impurity content of 10%nitric acid,are only 4.0677×10-6,these had a very small impact on the trial,completely negligible,but we found that Na element is the easiest introduction in the purification process;?2?When purification processing,using container 1 will be introduced Na,K and other impurity elements,it had great influence on the results of the test sample,but using the container 2 can avoided this phenomenon,significantly improve the purification effect.4.The optimization process applications experimental of 4N8 standard purity quartz by vein quartz.?1?After acid leaching,samples of different size had different loss rate,the smaller the particle size,the greater the loss rate,but the relationship is not linear,the finer the particle size;?2?VQ02 and VQ04,tow ores cannot be used for processing particle size of 80to 140 mesh,the purity of SiO2 reached 4N8 standard grade high purity quartz;?3?After processing,VQ03 and VQ09,meet Al element content less than16.2×10-6,meet the requirements of unimin IOTA-STD standard.Through this optimization process,VQ03 can be used for processing particle size of 80 to 140 mesh,impurity content is lower than 20×10-6,the purity of SiO2 reached 4N8 standard grade high purity quartz;?4?Compared with United States unimin standard grade samples of the XRD analysis and micrographs,VQ03,VQ09 are consistent among the phases and the appearance of the structure;?5?In summary,the optimization of process conditions,in particle size,chemical composition,phase and structure,VQ03,VQ09 have reached the U.S.unimin IOTA-STD requirements. |
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