China has begun turning waste from its coal mines into a new source of construction sand, a method that could ease pressure on rivers and quarries.
The key is in coal denima hard and polluting rock that, for decades, accumulated near mining explorations and was considered an environmental problem.
According to , the most notable case is located in Gaopingin Shanxi province, one of the country’s main coal regions. A recycling unit has come into operation at this location, capable of transforming this industrial waste into useful materials for the construction of infrastructures.
The installation produces approx. 1000 tons per day of sand, gravel and bricks. At first glance, the result could be confused with that of a conventional quarry, but its origin is very different. It comes from the waste generated after coal extraction and washing, a byproduct that can cause dust, water pollution and even fires.
The scale of the challenge explains China’s interest in this technology. The country accumulates around 7000 million tons of coal waste, according to available official data. Until now, less than 60% of this material had been reused, so a considerable portion continued to represent an environmental burden for mining-dependent cities.
The process combines automated x-ray separation, crushing, sieving and impurity removal. Subsequently, the material is transformed into manufactured aggregates and bricks with less environmental impact, as they do not require the firing phase at high temperatures.
Applications can also extend to ceramic industry and even the coatings used in space technology.
China consumes almost half of the sand and gravel used in construction worldwide, a demand that has harming ecosystems. Replacing part of the natural sand with mining waste reduces the accumulation of this waste and reduces the extraction of aggregates in rivers and quarries.
However, this advancement does not make coal waste a universal solution. Industry experts warn that these recycled aggregates continue to represent only a very small fraction of China’s annual consumption.
Furthermore, due to their structural limitations, they cannot be used in elements of high resistance or those subject to critical loads, such as pillars of skyscrapers or large bridges. It will also be essential to maintain strict toxicity controls to prevent heavy metals from infiltrating materials intended for housing.
Finally, old coal mining waste is beginning to be seen as a strategic raw material for construction, along with other projects aimed at extracting lithium, gallium or germanium from industrial by-products.
