Recycling of waste acid from titanium dioxide production
Thread Content
I want to use the waste acid generated in titanium dioxide production, with a concentration of 60%, for other manufacturing processes. However, it contains impurities of ferrous sulfate, and I would like to remove that ferrous sulfate. Who can do this?
Anhui Tongling Chemical Company possesses patented technologies; they have also built production facilities to remove ferrous sulfate from the waste acid resulting from titanium dioxide production, and use it in the manufacture of ordinary calcium carbonate, with excellent results.
Is there anything else? practically operated
Yes, there are such companies; Shanghai Xien Company has this technology. However, it seems that the efficiency is not very high except for in the case of ferrous sulfate, where it’s only 60%. You might want to consult them first.
They have equipment in operation at Shandong Dongjia Company
Except that the efficiency of ferrous sulfate is not very high, at only 60% – isn’t that too low? Is it the same thing you told me?
The treatment of waste acid from titanium dioxide production must be quite mature by now!
The equipment operated by Shanghai Xien at Shandong Dongjia was put into use two years ago; it seems to be idle now. The contract signed at that time specified the removal of 60% of the salt, but in reality less than 50% was removed. Moreover, the high water consumption led to secondary pollution, which is why this technology was developed back in 2005 – and it simply couldn’t be scaled up for widespread use.
Is that so? Are there no other technologies?
Sichuan Zhuoyue uses a three-effect evaporation method to concentrate waste acid to 60% through three stages of heating and evaporation. The concentrated sulfuric acid is then cooled and homogenized, before being pumped to a diaphragm filter press to remove ferrous ions. The sulfuric acid after iron removal is pumped back to the titanium dioxide production system via storage tanks. The heater is a tubular graphite heat exchanger, and the evaporator is steel-lined graphite.
I have here the flowcharts and equipment list for the on-site concentration of waste acid produced by Xuexia, and I can send them to you if you need them.