Ultrafine quartz powder is a high-quality neutral inorganic filler, due to its strong acid resistance, stable physical and chemical properties, good light transmittance, high dielectric, high humidity resistance, radiation resistance, excellent high temperature resistance and high Purity, low ion content, low expansion, low stress and other properties, widely used in plastics, rubber, paints, coatings, ceramics, inks and catalytic and gas filter materials and other fields. Moreover, ultrafine quartz powder is also a functional material, and its combination with new functional materials has shown broad application prospects, so the development of ultrafine quartz powder has practical significance.
The preparation of ultra-fine quartz powder requires the use of various mechanical equipment, including: ball mills, vibrating mills, stirring mills, jet mills, high-speed impact mills, colloid mills, etc., and fine grading equipment as supporting equipment. Among them, the high-energy ball milling method requires less equipment and simple process to prepare ultra-fine quartz powder, but there are many factors that affect the composition and performance of the final product. The main factors are raw material properties, milling intensity, milling environment, milling atmosphere, material-to-ball ratio, milling time and milling temperature.
01 Influence of raw material properties
The composition of the material system and the ratio of each component are the material basis for determining the composition of the final product. Different raw material compositions and component ratios will result in different ball milling products even under the same ball milling conditions.
02 Influence of ball milling strength
The high-speed and high-frequency impact and collision of the grinding medium on the material in the high-energy planetary mill is beneficial to the conversion of energy and the transport and diffusion of molecules, atoms and ions.
03 Influence of ball milling environment
There are usually two grinding methods for inorganic non-metallic grinding: dry method and wet method. The dry method is easy to operate, and the wet method can often obtain smaller particle size of the grinding product.
04 Effect of slurry concentration
In the process of wet ball milling, the slurry concentration is also an important process parameter, which is directly related to the particle size of the powder and the ball milling efficiency. It can be seen from the experiment that with the increase of slurry concentration, the effect of ball milling becomes better and better, but when the slurry concentration reaches a certain value, the influence of ball milling time on the particle size of powder becomes smaller.
05 Effect of grinding media size
Smaller cemented carbide balls, zirconia balls, alumina balls, etc. are often used in high-energy ball mills, because small-sized balls are conducive to increasing the friction area between the grinding medium and the material.
06 Influence of material-ball ratio
In order to obtain higher ball milling energy, the material-to-ball ratio is usually much smaller than that of ordinary ball mills. When the loading amount and the ball diameter are constant, the mean free path of the ball movement depends on the loading amount. When the amount of balls loaded is too small, that is, when the material-to-ball ratio is too large, the chance of the material being ground is reduced; on the contrary, if the material-to-ball ratio is too small, the mean free path of the ball is reduced, and its mechanical force cannot be fully utilized, thus reducing the chance of mechanical chemical reaction. degree.
07 Effect of ball milling time
The length of ball milling time directly affects the composition and purity of the milled product. The MA amorphization and crystal transformation of some metals or alloys can only be carried out within a certain time range. When the grinding time is too short, the internal energy accumulation of the material is too small to destroy its binding valence bonds; the grinding time is too long , and other chemical changes may occur. For the mechanochemical synthesis of inorganic non-metallic materials, ball milling for a long time is usually required.
08 Effect of ball milling rate
The effect of ball milling speed on product particle size is similar to that of ball milling time.
09 Influence of grinding aids
Grinding aids are chemical substances that can significantly improve crushing efficiency and reduce energy consumption during the powder preparation process, mainly surfactants, dispersants, etc. Adding a small amount of grinding aid during the ball milling process can improve the ball milling efficiency.
10 Effect of temperature
During the grinding process, due to the friction and impact of the ball mill on the powder, the temperature of the powder will rise, and the local temperature rise is conducive to the solid phase reaction, but the rise of the overall temperature will aggravate the agglomeration of materials and their interaction with the ball and the cylinder wall. Adhesion, when grinding some organic matter, the temperature is too high will lead to its decomposition and so on. It is generally believed that the temperature rise of the powder during grinding should not exceed 350K.