Around 400 ton/month of H2SO4 (spent) is generated as a by-product in our manufacturing process. This acid mainly consists of 40% H2SO4 and 4-5% HNO3. It is yellowish in colour and can have a small amount of organic material. The organic material consists of traces of solvent that is used in the process and finally gets separated from spent acid.
To convert this to usable product we have tried the following:
None of the above have given satisfactory results. The main constraint in processing H2SO4 is the presence of Nitric acid, occasional presence of slight organic layer and also issues related to safety.
We need a solution to convert this into a concentrated product (conc. > 70%) at low cost. The operating temperatures should not be greater than 80o C.