The beneficiation of silica ore is to increase the content of SiO2 in silica ore and reduce the content of other impurity minerals. The silica after beneficiation and purification is called silica sand. The higher the content of SiO2 in silica sand, the higher its value. Next, let's take a look at the process of silica ore beneficiation.
The specific process of silica pre selection is as follows: the raw silica is fed to the jaw crusher through the vibrating feeder for crushing, the crushed products are sent to the circular vibrating screen by the belt conveyor for screening, the qualified materials under the screen enter the next link, and the unqualified materials above the screen enter the crusher again for crushing.
The film iron and mud containing impurities on the surface of silica can be removed by mechanical force and friction between mineral particles. The main scrubbing methods include mechanical scrubbing, rod grinding scrubbing and ultrasonic scrubbing. The specific process of silica scrubbing is as follows: crushed silica is sent to the powder bin for stockpiling by the belt feeder, and then sent to the rod mill for grinding by the feeder. Qualified silica is sent to the blocked settler by the slurry pump to enter the next stage.
Magnetic separation can effectively remove magnetic minerals, such as hematite, including intergrowth, from silica, and the finer the silica particles, the better the iron removal effect. The magnetic separation process of silica should be formulated according to the specific use of silica after beneficiation and purification. There are two common types:
Silica separation process of foundry sand
The coarse concentrate treated by grinding and the first blocked settler is pumped to the second blocked settler for secondary settlement, and the qualified part is sent to the vibrating screen for treatment. The slurry left by screening will flow into the slurry pump and be sent to the tertiary sedimentation treatment, and the qualified concentrate obtained will be dehydrated through the dewatering screen to obtain the sand for casting.
Silica separation process of sand for glass
Glass sand has high requirements for the purity of silica, so its separation process is more complex than that of casting sand. As mentioned above, three-stage settlement treatment is adopted in the production of casting sand, and the lower part of the first settlement process in the three settlements is used to produce glass sand. The specific process is as follows: the slurry under the settlement flows into the flat magnetic separator for sorting operation to remove the impurities with weak magnetism. The products after impurity removal need to be settled twice, and the settled concentrate flows into the dewatering screen for dehydration treatment to obtain qualified silica sand concentrate for glass.
In order to further remove impurities and improve the purity of silica, flotation method is usually used. The flotation purified silica is mainly used to remove the nonmagnetic associated minerals such as feldspar and mica from the ore. The specific flow of silica flotation is: mining
With XFb single cell flotation machine, H2SO4 is used as the adjusting agent, pH=2.5-3, sodium petroleum sulfonate as the collector, and terpineol oil as the foaming agent, quartz is obtained by flotation. After flotation, mica can be removed by about 70%, and Fe203 content can be reduced to below 0.013%.
After grinding and settling, the impurities and minerals are directly sent to the thickener for thickening and dehydration. The dehydrated products are mixed through the mixing tank, and then pumped into the filter press for dehydration again, so that the water content is less than 20%, and then sent to the tailings pond for stockpiling with a belt conveyor.
The above is the process of silica ore dressing. Through the above five steps, the purity of SiO2 in silica can be improved. The purity after flotation is conservatively estimated to be more than 99%. If higher purity silica is required, acid leaching process can also be used. The specific process shall be determined through beneficiation test.
