Quartz sorting with laser

Top quality quartz for silica production is gained by means of laser sorting. This process requires coarse grained quartz (SiO2) that is reduced to silicon (Si) in melting furnaces.
Apart from a grain size of 20–120 mm, that quartz must have a low content of iron, aluminum and titanium.
After extensive tests in the test centre specialized to mining in Wedel near Hamburg, the first TOMRA multi-channel laser sorter for this sorting task has been brought into operation in October 2016 in a production line in Spain.
The customer mines wall gravel in open-pit mining, the gravel is pre-sieved in the mine, transported to the treatment plant, washed intensively, classified and sorted. To date, material with a grain size of 40–120 mm was sorted by hand. On average, this required 12–16 employees.
The installed laser sorter sorts the fraction of the grain size range from 20 to 70mm with a performance of 70t/h. The coarse fraction + 70 mm is still sorted by hand, but with fewer employees.
In addition to the reduced work costs and the safety issues, there are two other advantages:
  • The customer additionally sorts the fraction 20–40 mm, which increases the total yield of the plant.
  • They can now process worse wall gravel qualities which before could not be sorted into the required qualities manually. This increases the yield, the turnover, and the life time of the mine.

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