Purifying quartz sand - physical method

Physical purification quartz Silica sandis washed and classification desliming, scrub, magnetic separation, flotation and ultrasonic method.
1.1 washing and classification desliming this approach is mainly aimed at containing a large amount of clay minerals quartz sand. Because as quartz sand particles and the grade of the SiO2 decreases, and the grade of iron and Aluminium hydroxideimpurities such as mineral increase, so the rounding out the top of water concentration and classification of quartz sand ore desliming is very necessary, and the effect is also evident in the 18 j. It only as a method of the pretreatment of the ore candidate before application earlier are also common, but for the exist in the thin film on the surface of the quartz sand iron and adhesion impurity minerals, its removal effect is not significant. Scrubbing is 1.2 with the help of a mechanical force and sand grain peel force to remove the film on the surface of the quartz silica sandgrinding impurity iron, bonding and clay mineral and further chopped into single mineral aggregate, then through classification work to achieve the effect of quartz sand further purification. At present, the main two methods have good friction and mechanical scrubbing washing. For mechanical scrubbing, the related mechanical equipment structure, configuration and process flow of scrubbing washing time and concentration are the main factors influencing the scrubbing effect. Due to the factors that affect it too much, make the mechanical scrubbing the recovery rate is very low, only about 40%, so the mechanical scrubbing effect is not ideal. Compared with the mechanical scrubbing, great friction wash effect is much better than it. In great friction washing process, add the appropriate reagents, increase of impurity mineral and quartz particles on the surface of the electric repulsion, enhance impurity minerals and quartz particles mutual separation effect, increase the recovery rate of scrubbing to 80%, great friction wash is almost twice the mechanical scrubbing, but for the purification of high purity quartz sand, it is just a way of ore pretreatment. 1.3 magnetic separation magnetic separation method can remove the quartz sand particles maximum contains some impurities, hematite, limonite and biotite of weak magnetic impurities such as minerals and strong magnetic minerals mainly magnetite. Mineral often choose for weak magnetic impurities in strong magnetic machine more than 100000 e, for strong magnetic mineral impurities often adopt magnetic machine in the weak magnetic machine or magnetic separation. In general, the number of magnetic separation and magnetic field strength has important influence on magnetic separation effect of iron, with the increase of the number of magnetic separation, the iron content gradually reduce; And under a certain magnetic field strength can remove most of the iron, the magnetic field intensity even improve a lot since, in addition to iron rate also do not have changed much. In addition, quartz sand particle size is fine, in addition to iron, the better the results, the reason is that fine particle high mineral content of iron impurities of quartz sand. Tian Jinxing in experimental research progress of the study on the purification technology of high purity quartz sand, the results show that along with the increase of magnetic field intensity, impurity removal rate rise, magnetic field intensity of 100000 e, impurity removal rate increase is not obvious. Therefore appropriate magnetic field strength should be 100000 e. After magnetic separation, 40 mesh Si02 grade can reach 99.05%, with 0.071% Fe203:40-80 mesh Si02 grade is 99.09%, 0.070% Fe203 content; 80-140 mesh Si02 grade is 99.14%, 0.067% Fe203 content: 140-200 mesh Si02 grade is 99.10%, 0.069% Fe203 content. But are too many impurities in the quartz sand, especially containing more weak magnetic or nonmagnetic impurity, with magnetic separation is not only purified into high purity quartz sand. 1.4 flotation
Flotation is to remove the quartz sand in feldspar, mica and other non-magnetic minerals associated impurities. At present there are mainly with fluorine flotation and two methods of fluorine-free flotation. Fluorine flotation is using cationic collector and hydrofluoric acid as activator in the acidic pH range. But given the fluoride waste water serious impact on the environment, people are turning to non-fresno flotation. Use of quartz, feldspar differences in structure, reasonable ratio of ion of Yin and Yang of mixed collector with depth and dosage, using their Zeta potential of different, preferential flotation of feldspar, realize the separation of the two llo,. Have been reported in the neutral condition, join non-fresno flotation reagents, the silica micro powder Si02 content increased from 99.1% to 99.1%, accordingly Fe203 content decreased from 0.081% to 0.081%, a 85% yield at 83%. This indicates that no flotation can significantly improve quality of silica micro powder. Shang Yafei, sodium hexametaphosphate as dispersant and flotation agent, twelve amine collector, can remove the iron impurities from quartz fine powder, Fe2O3 content from 0.09% to 0.02%, the yield reached 85%. 1.5 the ultrasonic method, ultrasonic method is a kind of sound waves, depending on the media to spread it is mechanical energy, in the heart of the communication process will cause interaction with the media, to produce a variety of effects (mechanical effect, thermal effect and the cavitation effect). Using ultrasonic grinding head on the liquid, the liquid internal changes, pressure or tension, when the tension reaches a certain intensity, produce cavitation effect, causing the tiny bubbles, the bubbles with ultrasonic vibration is compressed stress decreased; When the bubble reaches a critical scale (the scale determines the frequency of the ultrasonic wave), the bubble will burst, produce a great pressure, engaged in fierce impact of solid particles in liquid, under the intense impact, trace impurity or water film on the surface of the particles, quickly from the particle surface spalling, suspended solids under the action of dispersant, become a subtle, from quartz sand, after washing the separation, to make the purity of quartz sand is greatly improved. Liao Qing in water and a small amount of dispersant media such as medium, the 0-15 mm depositional quartz sandstone particles, powder by ultrasonic treatment, including Fe2030.12 %, quartz sand to contain Fe2030 S10299.42 %. 01%, 8 i0299. 8%, recovery rate over 99%, reached the standard of optical glass with sand.