Experimental Study Of Processing Low Iron Quartz Sand Used For Ultra White Glass By Quartzose Sandstone Of Muchuan Huangdan, Sichua

Low iron quartz sand is the main raw material of ultra white glass including solar glass, upscale automobile glass, high-grade construction glass and so on. In recent years, Chinese photovoltaic industry is developing very quickly. Due to the rapid development of China photovoltaic industry, the demand of solar glass increased year after year, causing dosage of high-quality low iron quartz sand has been on the rise. There is quite big gap existed in raw material of high-quality low iron quartz sand in some places and this can just play a very limited role in satisfying the needs of the national economic economy construction.The reserves of quartzose sandstone mine in Huangdan, Muchuan County of Sichuan is above ten millions of tons. The scale is very large and the mining condition is good with convenient transportation. If the quartz sandstone there can be purified and processed, this region will become the base of high-quality low iron quartz sand supply and promote the development of glass and new energy industry of Sichuan. This also will convert the superiority of mineral resources to the superiority of economy. In order to provide a scientific basis for the purification and utilization of the quartzose sandstone in Huangdan, Muchuan County of Sichuan, the study of mineralogical characteristic and mode of occurrence of Fe element have been carried out for this quart sand via variety modern test and analysis method, including polarizing microscope, XRD, XRF, SEM-EDX, etc. Based on this, using pilot sample (HZ06-08) and adopting the integrated processing technology, we did further processing purification and successfully developed low iron quartz sand with its components meet the industrial standard for ultra white glass. The main research results or progresses are as follows:1.The characters of petrology and mineralogy of quartzose sandstone of Muchuan Huangdan: The mine is a kind of silicon muddy containing feldspar quartz sandstone. The range of quartz sandstone sand with grain shape of clastic texture, no directional massive structure. The particle size range of quartz debris is from 0.2 mm to 0.5mm(32 mesh -80 mesh). Its raw ore chemical composition change range respectively is: SiO₂91.23-97.79; Al₂O₃1.80-5.97; Fe₂O₃0.04-0.39; TiO₂0.0291- 0.2533; CaO 0-0.061; MgO0.02-0.19;K₂O 0.3238-1.9233; Na₂O0.0003-0.0171. This raw mine is mainly composed of quartz , which is about 90%, with high degree of crystallinity and high purity . Meanwhile, there are still a few or a small amount of other mineral impurities, including illite, montmorillonite, kaolinite, microcline feldspar and calcite, as well as pyrite, rutile, brookite, zircon , etc.2. The occurrence of iron and other impurities in quartzose sandstone of Muchuan Huangdan: Al₂O₃, K2O, CaO, MgO style etc harmful components occur in illite, montmorillonite, kaolinite, microcline feldspar and calcite in minerals such as. TiO2 occur in rutile and brookite. Fe₂O₃ mainly occur in pyrite, also have stems partly from clay minerals between quartz particles or the small dissolution pit on the grain surface of quartz, and trace Fe₂O₃ from rutile and plate over-mining etc.3. The research of miniature magnetic iron-separating device: according to the job needs and ore characteristics, a kind of miniature magnetic iron-separating device with magnetic field intensity of 10,000 gaussian has been developed and it has been proved to be reasonable design and remarkable effect after mine separating test. It is especially applicable to the study of magnetic separating, processing and purifying of small amount of mine sample.4. The magnetic separation for removing iron purification experiment of quartzose sandstone of Muchuan Huangdan: magnetic separation technology experiment showed that sample heating temperature of magnetic separation for removing iron purification have great effect and the suitable roasting temperature is 450℃. Roasting can ascend magnetic separation an effective removal, because roasting treatment can change the pyrite iron-bearing minerals such as the magnetic characteristics, make its magnetic enhanced. Except quartz, the separated component by roasting includes pyrite, microcline, illite, kaolinite, rutile, brookite, zircon and calcite etc. The acid pickling experiment for magnetic material shows that in the purification processes the magnetic separation is a very important link.5. The pickling for removing iron purification experiment of quartzose sandstone of Muchuan Huangdan: Pickling process experiment showed that acid pickling type on removing Fe have certain effect, comprehensive consideration of the hydrochloric acid is preferred. The heating temperature of sample have great effect on acid pickling on removing Fe and the best effect is at 400℃or so of roasting. Taking the upstream technology into consideration, 450℃is to optimize the roasting temperature; acid pickling time experiment showed that the extension of pickling time can effectively improve the quality of the sample and the appropriate pickling time is 6-10h.6. The optimization experiment of processing low iron quartz sand used for ultra white glass by quartzose sandstone of Muchuan Huangdan: optimization experiment indicate that, according to the above results by adjusting the initial sample size and tail treatment, of ascension threw sample have more apparent effect. Adopting the optimization process, we can processing the low iron quartz sand with its components meet the industrial standard for ultra white glass. Its chemistry component (wt%) is: SiO₂99.47,Al₂O₃0.39,Fe₂O₃0.013,TiO₂0.0238,MgO 0.01,K₂O0.1023. The optimized process was: particle size -60⁺140 mesh; sample roasting condition: 450℃for 1h; magnetic field intensity 10000GS for 6 times; Pickling condition: 20% HCl, pulp concentration 40%, pH 1.5, temperature of water bath 80℃, time of pickling 10h.