A factory on the island of Phu Quoc in southern Vietnam has started turning sea sand into construction sand using a method patented by a Vietnamese engineer some eight years ago, VN Express reports.
There is a global shortage of construction sand, but sand from deserts, beaches or the sea bed cannot usually be used because desert sand grains are too round and fine, and sea sand contains impurities. Â
Vietnam has been one of the countries most concerned about the issue: last year the Ministry of Construction made an official declaration that the country may run out building-grade sand altogether by 2020 (see Further Reading, below).
In 2011 the engineer Vo Tan Dung developed a technique for blasting beach sand with water to remove salt and organic impurities, then filtering it to get the right mix of grains.
A test by the Vietnam Institute for Building Science in March last year found that the amount of dust, clay, organic impurities and mud dropped significantly in the beach sand, making it suitable for construction.
Now, the technique has been licensed by Phan Thanh Construction, and the company has completed the factory on Vietnam’s largest island capable of producing 200 cubic metres of construction-grade sand an hour.
Dung said he hoped the sand cleaning technique will contribute to cooling down the construction sand fever that has been raging across Vietnam, leading to "sand mafias" extracting the material illegally from rivers and coastal areas.
A report by the UN Environment Programme in May warned that with global demand for sand and gravel was at an unsustainable level – 40 to 50 billion tonnes a year – and that extraction from rivers had led to pollution, flooding, lowering of water aquifers and worsening droughts.
Image: The Phu Quoc factory in operation (Phan Thanh Construction)