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One invention helps a local industry to flourish

The Micron mill was used in a variety of fields such as cosmetics, pharmaceuticals, lead powder, dyes, pigments and paints. Amongst other things, they were widely used to produce heavy  calcium carbonate, a powder made by grinding limestone, which is found in many parts of Japan. If you think that there is such a thing as "heavy", then there must be such a thing as "light", you would be correct. They are called "GCC" and "PCC" for short, and sometimes collectively "charcoal". Our machines are used in the production of both types of powder. For more information on the uses of these powders, how they are made and the differences between them, please visit the websites of the Japan Lime Association.
Now, GCC is a material that is often mixed with something else. It is therefore difficult to mix and use unless it is made into small particles (fine powder). Until the beginning of the Showa period (1926-1989), it was very difficult to reduce limestone to such a small size. For example, in the Chugoku region in Japan,  one of the main limestone producing areas, especially in the mountainous areas of Hiroshima and Okayama Prefectures, the following process was adopted to produce such fine powdered GCC.

  1. Limestone is dug out of the mountain and crushed.
  2. The crushed limestone is further ground into small particles in water (wet grinding).
  3. The liquid mixture of water and fine limestone is divided into heavier and lighter (smaller) particles.
  4. The lighter particles are removed from the liquid.
  5. Drying to obtain particles smaller than 10 μm.
GCC factory

This was a very time-consuming and energy-intensive process.
However, with the advent of the Micron mill, it became possible to produce large quantities of fine powder in a dry process, i.e. without the use of water. This had a tremendous impact on the industry, and between 1931 and 1941, several hundred units were delivered, setting off a movement in the heavy coal industry in the Chugoku region.