| abstract |
Apparatus and method for regenerating spent pickling liquor from the acid pickling of a metal are disclosed. Acid pickling of a metal uses a first acid and forms a spent pickling liquor (SPL). A second acid added to the spent pickling liquor, under specificlow temperatures produces a metal salt of the second acid. The me salt of the second acid is crystallized and removed from a regen first acid. In one aspect, hydrochloric acid is regenerated fropickling process for iron or steel, using sulfuric acid as the seacid, and ferrous sulfate heptahydrate crystals are produced. Regenerated hydrochloric acid is recycled to the acid pickling process. |