The iron impurities in quartz sand mainly exist in the form of Muscovite, pyrite and ferric oxide. The existence of iron impurities greatly reduces the use value of quartz sand and affects the quality of the product. In actual production, quartz sand iron removal needs water elution raw materials, and then mechanical scrubbing, magnetic separation, flotation, ultrasonic cleaning, acid leaching, etc., to remove the iron element in quartz sand, improve the use value of quartz sand. So, how much quartz sand is the most suitable for mineral processing and purification?

      The content of Fe₂O₃ in quartz sand with particle size greater than 60 increases with the increase of particle size, and the content of SiO₂ decreases with the increase of particle size. The content of Fe₂O₃ in 50-mesh quartz sand is as high as 0.0522%, and the content of SiO₂ is the lowest at 98.32%. This is because the particle size of +50 mesh quartz sand is larger than that of quartz particles, so there will be many quartz particles in a single quartz sand particle, and the iron inclusion between quartz particles is not separated, resulting in the increase of iron content in +50 mesh quartz sand.

      The content of Fe₂O₃ and SiO₂ in quartz sand with particle size less than 180 increases with decreasing particle size, and the content of SiO₂ in quartz sand with particle size less than 180 decreases with decreasing particle size. Among them, the content of Iron in quartz sand with -300 mesh is as high as 0.0587%(3 times of quartz sand sample with -200 300 mesh), and the content of SiO₂ is the lowest at 98.81%. This is mainly because the particle size of iron-bearing minerals in quartzite is generally less than 0.01M. When quartzite is ground to 50μ M, most of the iron-bearing minerals in the impurity phase of quartz fall off into -300 mesh quartz sand, resulting in high iron content in -300 mesh quartz sand.

      The above data indicate that the smaller the particle size, the higher the impurity content, which is why quartz sand is graded and de-bonded prior to beneficiation and purification. In addition, the variation of iron content with grain size of quartz sand is as follows: When the grain size of quartz sand is more than 60 mesh, the iron content increases with the increase of grain size. When the grain size of quartz sand is less than 180 mesh, the iron content increases with the decrease of grain size.

      Therefore, in the separation and purification process of quartz sand, the first raw material for washing mud, quartz sand particle size control between -60 ~ 180 mesh, effectively improve the quality of the product, reduce the content of iron impurities in the quartz sand. For quartz sand with particle size greater than 60 mesh and less than 180 mesh, magnetic separation can be strengthened to effectively reduce the content of iron impurities in quartz sand.