Recycling of dilute hydrochloric acid/sulfuric acid
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Located in Yunnan, the extraction of traditional Chinese medicines generates acidic waste liquids with a pH of around 2, consisting of hydrochloric acid or sulfuric acid; the concentration is estimated to be a few hundredths percent, with volumes of 10 tons per day each. This poses a significant burden on the wastewater treatment system. I am seeking solutions for recycling these wastes; I’m not sure whether it’s possible to recycle them. Thank you very much.
Sulfuric acid can be recovered using a sodium filter membrane; the filtrate obtained after this process is then used in an RO process to recover hydrochloric acid, which allows for a 80% reduction in consumption
Regarding the sulfuric acid concentration mentioned last year – it seems that with GE’s membranes, a recovery rate of around 12% can be achieved, while the recovery rate is about 90%. What is the progress now? Is it convenient to let me know?
The membrane is fine now; it’s the high-pressure pump that has a problem – the corrosion on the pump is quite severe
Hydrochloric acid can have the water removed from it through vacuum distillation. By increasing the acid concentration to the azeotropic acid concentration, the top of the tower contains virtually no acid. Sulfuric acid is also concentrated using such methods; current technologies for concentrating sulfuric acid are quite mature
After checking around, the concentration is too low – only a few parts per thousand. Energy is required to increase it, and currently sulfuric acid costs only a few hundred yuan per ton, so it’s not cost-effective. It is only worthwhile to concentrate by more than 10%, or when there are metal by-products such as iron in the acid.
How much does it cost to increase the sulfuric acid concentration from 30%–40% to 75%?
How much does it cost to increase the sulfuric acid concentration from 30%–40% to 75%?