Quartz – Silica
Quartz is a crystalline mineral of silicon dioxide, also referred to as Crystalline Silica. Quartz is the most abundant mineral on the earth’s surface and the second most abundant mineral in the earth’s crust. Beach and desert sand is primarily composed of quartz crystals due to quartz’s high resistance to mechanical and chemical weathering. Quartz can be found in sand deposits, high purity crystal deposits and is found to some degree as a minor component in most mineral formations.
Quartz is highly abrasive with a Mohs hardness value of 7.0. It is also very chemical resistant and durable.
Ground quartz is used as fillers in the paint, adhesives and plastic industries. Quartz powder provides strength, durability and resistance to wear. It also provides chemical inertness. Ground quarts can be added to achieve high solids content with low viscosity impact. High purity quartz will also provide a bright whiteness.
The most common equipment that Hosokawa provides for the milling of quartz is the Hosokawa Alpine Super-Orion Ball Mill in circuit with a Hosokawa Alpine Air Classifier. For quartz applications, the ball mill will typically be constructed with Aluminum Oxide media and ball mill lining. The most common Hosokawa air classifier used for quartz is the Hosokawa Alpine Stratoplex (ASP) which is used for a cut point (top size) of 20 to 200 microns. For super-fine applications, the Hosokawa Alpine Turboplex (ATP) air classifier is used, with a cut point (top size) of 5 to 50 microns, with single and multi-wheel options. Both classifiers are made with Aluminum Oxide Classifier Wheels, and with interior Aluminum Oxide tiling for both fine grinding and durability. Hosokawa has the experience and expertise to set up quality systems for these challenging applications.
For very high purity applications, the Hosokawa Alpine AFG Fluidized Opposed Jet Mill is the mill of choice. The particle-to-particle impact avoids equipment wear providing a high purity product. In the Hosokawa Alpine AFG Jet Mill, material is fed into the milling chamber to form a bed. Opposing nozzles create high speed air streams (up to 1000 MPH) which fluidize the powder and cause the powder to impact against each other in the center of the chamber. The flowing air eventually rises up the chamber and flows into the rotating classifier wheel, which allows the particles which meet the particle size specification to flow through, while forcing the larger particles to fall back into the fluidized bed and be re-ground. Various pressures, nozzle sizes and variable speed classifier wheel provide a wide range of particle sizes that can be achieved with the AFG Jet Mill.