Information profile @ a Glance
- Steel pickling is part of the finishing process in the production of
certain steel products in which oxide and scale are removed from the
surface of strip steel, steel wire, and some other forms of steel, by
dissolution in acid.
- Both sulfuric and hydrochloric acid are in common use for the
pickling of steel to be galvanized
- Hydrochloric acid is not without disadvantages, for example, more
tankage is required because the
pickling rate is 1/3 slower, and the price of the acid per ton pickled
is higher than sulfuric. Also, spent sulfuric acid can be reclaimed by
refrigeration based processes whereas no current process effectively
recycles hydrochloric.
- PICKLING is the chemical removal of surface oxides or scale from
steel by immersion in an aqueous acid solution. While wide variations
are possible in the type, strength and temperature of the acid solutions
used, sulfuric and hydrochloric acids are the most common pickling acids
for carbon steel.
- Pickle liquors become contaminated with dissolved metals through
use. As the metal concentration increases, the free acid concentration
decreases and pickling efficiency
drops. Additions of fresh concentrated acid are made from time to time
to rejuvenate the bath but eventually it becomes spent and must be
discarded
- Recovery of spent pickle liquors can potentially reduce many of the
costs.
- Plants are for regenerating exhausted pickling solutions from
sulfuric acid pickling baths
- In these plants, the ferrous sulphate accumulated in the acid is
crystallized by cooling and separated as ferrous sulphate heptahydrate
- The pickling of mild steel sheets with sulfuric acid produces an
aqueous waste stream containing ferrous sulfate and sulfuric acid.
Cooling of that solution forces ferrous sulfate to crystallize as
FeSO4.7H2O. From the viewpoint of the mother liquor composition, this is
a way to purify the solution.
- At the same time, the seven molecules of water that is removed with
the crystallized ferrous sulfate causes the reconcentration of the
sulfuric acid. The solution thus treated can be recycled to the pickling
bath.
- Ferrous sulphate is a compound largely used in agriculture
|
Basic Information
-
About Sulfuric Acid Pickling and Recovery
-
Hot dip Galvanizing
-
Spent pickling liquor
-
Sulfuric Acid Plants
Technology Information
- Spent Acid Regeneration Technology
- Sulfuric acid & Ferrous sulfate recovery from spent pickling liquor
- Sulfuric Acid Alkylation Technology
- Regenerating spent pickling liquor
- Recovery of spent sulfuric acid from steel pickling operations
- Recovery Process of
pickle liquors
- Mass Crystallization from solutions
- Spectrophotometric determination of iron(III) and total iron by
sequential injection analysis technique
- Waste Pickle Liquor recovery process patent
Industry Scenario
- Company - USA
- Company - Service Provider
- Pickling acid recovery unit purifies spent sulfuric acid
- Best Available Techniques in the Ferrous Metals Processing Industry
- Recovery of acid and oxide by-products from spent pickling liquor
- Waste Iron Sulphate
- Dezincing of Galvanized Steel
Project / Equipment Suppliers
- Regeneration plants for sulfuric acid pickling
- Technology offer
- Chinese Technology
- Equipment supplier
- Project Consultant
- Processes for reducing production cost
- Red iron oxide - project profile
Order the CD ROM Today |