A production line produces high-purity, low-iron quartz sand from construction waste. [Photo/en.xmu.edu.cn]
A research team led by Associate Professor Xu Qingchi of Xiamen University has developed an innovative mineral recovery system that converts industrial waste into high-value raw materials. By applying fluid dynamics and physical screening principles, the technology reduces energy consumption while yielding significant financial returns for small and medium-sized enterprises.
The breakthrough addresses inefficiencies in traditional tailings recovery, which often results in the loss of 12 to 15 percent of fine sand through high-power slurry pumps. Associate Professor Xu's team introduced a specialized decelerator at the front end of conventional sand washing machines. This device slows the water flow to increase sedimentation time, capturing an additional 800 to 1,000 metric tons of sand daily and reducing total tailings waste by up to 15 percent.
Beyond tailings, the research team also works on transforming construction waste into high-purity minerals. Through a zero-emission process involving high-pressure washing and magnetic separation, the team extracts quartz with over 99 percent silica purity, meeting the rigorous standards for photovoltaic glass production. Other byproducts, including porcelain clay and magnetite, are reclaimed for industrial use, while process water is entirely recycled.
Currently deployed at a pilot project in Nanjing county, Zhangzhou, Fujian province, the technology processes one million tons of construction waste annually. The project generates 300,000 tons of high-quality quartz sand and provides localized raw materials for the solar industry while preserving land resources and eliminating secondary pollution.
