Research On Novel Technology Of Reverse Flotaton And Purification By Pressure Leaching For Vein Quartz

Prepare ultra high purity quartz from vein quartz which is abundant deposited,can provide key functional materials for solar energy, optical fiber, semiconductor,integrated circuit, laser, aeroppace, military, nuclear energy (radiation protection),borosilicate glass. In this study, magnetic separation, reverse flotation, hot-pressingleaching were used to prepare ultra high purity functional quartz from vein quartz ofSichuan.The mineralogy analyses showed that the main inclusions in the quartz aremineral inclusions and fluid inclusions. Inclusions in the size of1-5μm mainlydistribute like tape, band or clumps, aggregate near the cracks of the grains. And someinclusions smaller than1μm, take the cloud-like dispersion distribution. Test resultsshow that the homogenization temperature of fluid inclusion is200℃-400℃, itindicates that when heated above400℃, these fluid inclusions will be eliminated. Themain impuritie minerals in the quartz are mica, feldspar, ferrous mineral, pyroxeneand secondary contamination of iron. The oxide content of main metal impurityelements are as follows/μg.g-1: Al2O3144.45、Fe2O391.86、Na2O63.13、K2O37.19、CaO53.7、MnO10.64, accounting for88%of the content of total metal impurityelements. Some mica and feldspar that exist in the form of macroscopic grain can beseparated by flotation, but most impurities are in the quartz grain with the form of tinyinclusions, and can hardly separated by general mineral processing method.Firstly, high gradient magnetic separator was used in the experiment to separateimpurity minerals with magnetism. When magnetic density is1.2T, pulsationfrequency is300r/min, the impurity element removal rate of the concentrate quartz inthe magnetic separator operation are as follows/%: Al12.94, Fe38.82%. The resultshows that: high gradient magnetic separator can remove iron chips and part ofdisintegrated magnetic minerals effectively.Other impurities minerals that have been disintegrated were separated byflotation. Flotation experiment was composed of three parts: the reverse flotation offerrous mineral carried out in sodium oleic system under neutral condition; starch wasused to inhibit quartz in the reverse flotation of mica; mixed collector was used toseparate feldspar. After flotation, the total amount of impurities element in the quartzsands were decreased by117.1μg/g, the removal rate in flotation operation is40.93%. Finally, to remove inclusions wrap in quartz grain, roasting-water quenching wasused, trying to make fracture on the interface of mineral inclusions and quartzes, andproviding favorable conditions for leaching. Orthogonal experiments of leachingunder constant pressure at60℃have be taken in different particle size; pressureleaching of different particle size have be taken at150℃and200℃. The resultsshowed that: roasting-water quenching pretreatment can making fracture in theinterface of mineral inclusions and quartzs for different thermodynamic property.In a pressurized environment, the rise of temperature, the increase of activationenergy and amount of activated molecule, enhanced the speed of metal bond breaking,produced more crystal defects on the interface of mineral inclusions and quartzs, andincreased chemical activity of high energy region. All of this speed up the chemicalreaction between metal elements and acids, and purify the quartz.