Ground calcium carbonate (GCC) is used in papermaking as a filler as well as a coating pigment for surface finishing, whereby the ultimate fineness of the final product is achieved only by single or multi-stage milling processes using GAW Ultramill technology.
GAW technologies Ultramill.
The vertical GAW Ultramill is unique as an extension of conventional horizontal grinding ball technology. It enables the treatment of particles of the desired order of magnitude adapted to the application.
The agitator ball mill is made of mild steel/stainless steel. The parts that are particularly exposed to moisture are made of highly resistant composite material lined with resistant and contamination-free polyurethane resin. The grinding chamber, which is encased in cooling water, is divided into different sections for easy inspection and maintenance.
The grinding discs are built in an exclusive GAW design. They are configured in a modular concept to enable different-end- product characteristics.
All operating parts (e.g. grinding discs, spacers, ball separators and the intake rotor) have been designed to slide over the shaft in any required configuration. This feature provides great flexibility in design, optimizes energy consumption, milling efficiency and maintenance costs.
Depending on the design and intended application, the mill is filled with grinding media of adequate diameter. The product to be ground is introduced through the distributor at the bottom of the mill.
For this purpose, a controlled pump with adjustable speed is used, regulated by a mass flow meter (Coriolis principle). Performance, particle size distribution, fineness and the grinding speed of the system are managed by automated production control. Immediately after entering the mill via the distributor at the bottom, the product is homogeneously dispersed by the intake rotor and the bottom grinding disc.
The agitator ball mill drive is equipped with a frequency converter. As a result, the rotational speed and configuration of the grinding discs can be optimized. As soon as the product is dispersed, the product and grinding balls rise in a spiral- like rotary motion to the height of the agitator ball mill.
The spiralling, upward movement provides a zone of high pressure while a low-pressure zone forms around the shaft.
The strong vortex movement prevents the exit of the grinding balls because they move along the shaft, spiralling downward. The rotation of the grinding media takes place in a closed circuit. In combination with the tremendous working speed, this achieves the ultimate grinding efficiency.
GAW Ultramills grindl calcium carbonate into fillers and ultrafine coating pigment. It achieves fineness from 60% ≤ 2 micron up to 98% ≤ 2 micron. Hundreds of installed agitator mills in GCC grinding plants worldwide ensure system capacities of 30,000 tons up to 1,000,000 tons per year.