Sand is a highly sought-after raw material and is used, among other things, for the production of glass and computer chips. However, by far the largest part is processed in construction. Because sand is absolutely necessary for the production of concrete. The global construction boom of recent years has helped annual sand consumption triple to about 50 billion tons. The problem: Sand cannot be produced just like that, but is the result of long-term natural processes. Moreover, sand is not just sand. For example, the abundant desert sand cannot be used for the production of concrete. As a result, the deposits that can be developed without any problems are slowly running out. In some cases, therefore, entire stretches of coast are illegally cleared. Or sand is removed from the seabed – which shakes the local ecosystems enormously. Scientists from Australia and Switzerland may have now found a solution.
Mining waste is piling up in gigantic quantities
They are dependent on so-called ore sand. It will also be demolished today. Because it is a waste product of mining. Mining waste is generally produced in huge quantities. It is estimated that this is the largest waste stream of all, with 30 to 60 billion tons per year. The mining companies all have to make a huge effort to safely store these amounts of unwanted material. This does not always work: in Brazil alone, there have been several fatal accidents in recent years due to dam breaches at catchment basins. However, if the sand-like materials could be separated and sold to the construction industry at an early stage, it would greatly reduce the quantities produced. The researchers therefore teamed up with mining company Vale and took corresponding samples at a Brazilian iron ore processing plant. The result: some of the alleged waste can actually be used as a substitute for sand in industrial processes and in the production of concrete.
The ore sand can in many cases be used locally
Theoretically, this could solve two problems: less sand should be extracted from environmentally hazardous locations and the amount of mining waste would be reduced. The climate can also benefit. However, the balance here largely depends on the transport routes. The researchers therefore examined the location of the mines in question. At least a third of them have a sufficiently large demand for sand within a radius of less than fifty kilometers. Only China would be able to replace one billion tons of sand per year in a climate-friendly way. The challenge now is to develop processes with which the valuable ore sand can be separated easily and cheaply from the rest of the waste stream. It could help in this regard that, for example, the Brazilian government has already issued stricter rules for handling mining waste. So the corporations would be happy to get rid of at least some of it.
Via: The Standard