Oxidation with Chrome(VI) in a sulfuric acid medium is a widely used oxidation process in the pharmaceutical industries. After the oxidation step the synthetic product is usually extracted into a hydrophobic organic solvent, and the remaining Chrome(III) containing aqueous phase is collected in tanks. The remnant Chrome(VI) content of the aqueous phase is usually reduced to Chrome(III) by sodium-sulfite, and later via the addition of Ca(OH)2 the Chrome content is precipitated in the form of Cr(OH)3. The Chrome-hydroxide precipitate and the co-precipitating CaSO4 are washed, and are deposited as hazardous waste. For the subsequent oxidation steps brand new Chrome(VI) and sulfuric acid are to be used.
As a by-product of a medicine intermediate production such a Chrome(III) containing sludge is produced in the Dorog Affiliate of the Gedeon Richter pharmaceutical company. Applying the electrochemical technology of the G.I.C. Ltd., the Chrome(III) content of the reaction mixture can be regenerated to Chrome(VI), and then re-used as an oxidizer in the intermediate production process.
Major advantages of our Chrome regeneration technology are the following:
- Chrome containing waste is not produced during the intermedier production. It is not needed any more to buy new
- Chrome(VI) containing chemical for the subsequent batches of the production.
- Working with carcinogenic Chrome(VI) containing powders can be avoided completely; the Chrome content is present always in a dissolved form.
- During the regeneration, the organic content of the aqueous waste is also eliminated.
The electrochemical regeneration technology removes all the heavy metal traces that get into the solution during the production.
Summarizing the advantages of our technology one can state that the regeneration of the Chrome(III) content and the removal of the remaining organic content are carried out simultaneously allowing the complete re-using of the Chrome content as oxidizer in the subsequent batches of the intermediate production.