Photovoltaic plant drinks 300 tons of hydrofluoric acid in a year: diffusion dialysis does not plug in electricity, sending the acid in the waste acid back to the production line

A medium-sized fluorite mine with an annual output of approximately 50000 tons of fluorite. The hydrofluoric acid consumed by China's photovoltaic industry in a year is equivalent to consuming several such mines - with a battery production capacity of over 1000GW at the manufacturing end, 200-300 tons of hydrofluoric acid are used per GW per year for silicon wafer production, cleaning, and etching. Where did the used acid go? Most of them turn into fluorine-containing waste acid, and spend disposal fees and pile up fluorine-containing sludge to leave the site. The industry data is shocking: in 2026, the theoretical production of hydrofluoric acid from industrial waste in China is about 450000 tons, of which 62% have a concentration higher than 30% and high recycling value - that is to say, nearly 280000 tons of "usable acid" are treated as wastewater every year.
Diffusion dialysis (DD) is the most low-key membrane family: without power or pressure pump drive, it relies solely on concentration differences to work. A stack of anion exchange membranes separates a thin channel, with waste acid flowing on one side and clean water flowing on the other side - acids (hydrogen ions and fluoride, nitrate ions) freely pass through the membrane along the concentration difference, while metal ions and impurities are blocked in place by the membrane. The result is one in two out: the recovered acid flows out from the clean water side and can be directly replenished to the velvet making tank; The concentration of metals and fluorine in the residual liquid increases and the volume decreases, and it is handed over to the next station for centralized processing. The only power consumption in the entire process is a few transfer pumps, and the "membrane passing cost" of one ton of waste acid is often less than half an kilowatt hour - an order of magnitude lower than thermal processes such as evaporation and distillation.
Fluorite is a strategically controlled mineral, and fluorine is the lifeline that both chips and photovoltaics cannot escape - dumping the acid in waste acid not only incurs disposal costs, but also an 'invisible fluorite mine'. What diffusion dialysis does is this: without plugging in electricity, send the acid back to production