Steel pickling

Pickling agent Pickling of steel Pickling solutions Pick s disease Pidoram [1918-02-1]... 

The balance of hydrogen fluoride is used ia appHcations such as stainless steel pickling inorganic fluoride production, alkylation (qv), uranium enrichment, and fluorine production. Hydrogen fluoride is used to convert uranium oxide to UF which then reacts with elemental fluorine to produce volatile UF. ... 

In the North American HF market, approximately 70% goes into the production of fluorocarbons, 4% to the nuclear industry, 5% to alkylation processes, 5% to steel pickling, and 16% to other markets (41). This does not include the HF going to aluminum fluoride, the majority of which is produced captively for this purpose. 

Sa.lts Salting out metal chlorides from aqueous solutions by the common ion effect upon addition of HCl is utilized in many practical apphcations. Typical data for ferrous chloride [13478-10-9] FeCl2, potassium chloride [7447-40-7] KCl, and NaCl are shown in Table 9. The properties of the FeCl2-HCL-H2 0 system are important to the steel-pickling industry (see Metal SURFACE TREATMENTS Steel). Other metal chlorides that are salted out by the addition of hydrogen chloride to aqueous solutions include those of magnesium, strontium, and barium. 

Aqueous Hydrochloric Acid. Muriatic acid consumption in 1993 was about 1.57 million metric tons (100% basis). The largest captive use of aqueous HCl is for brine acidification prior to electrolysis in chlorine/caustic cells and the largest merchant markets for HCl are steel pickling and oil-well acidizing, which accounted for 25 and 16% of merchant production, respectively, during 1989. 

Metal Cleaning. About 204 thousand metric tons of HCl (100% basis) was consumed in 1993 for steel pickling, wherein the hydrochloric acid readily dissolves all of the various oxides present in the scale formed during the hot rolling process. Using suitable inhibitors such as alkyl pyridines, HCl reacts very slowly with the base metal rendering the surface so clean that it must be passivated with a mild alkaline rinse. 

Reduce nitrogen oxide emissions by use of natural gas as fuel, use low-NO, burners, and use hydrogen peroxide and urea in stainless steel pickling baths. 

Parker Amchem. Rodine Acid Inhibitors for Industrial Cleaning and Steel Pickling Operations. Technical and marketing document. Parker Amchem, Inc. (Henkel), USA. 

Wet air pollution control (WAPC) devices are used to treat exhaust gases from stainless steel pickling operations, thereby generating wastewater, which are treated using the selective catalytic reduction (SCR) technology in which anhydrous ammonia is injected into the gas stream prior to a catalyst to reduce NO, to nitrogen and water. The most common types of catalysts are a metal oxide, a noble metal, or zeolite. 

Pickling is conducted by continuous, semicontinuous, or batch modes depending on the form of metal processed. In developing a National Emission Standard for the steel pickling industry, U.S. 

Source U.S. EPA, Steel Pickling, U.S. Environmental Protection Agency, Washington, DC, June 2008. Available at http //www.epa.gov/tri/TWebHelpAVebHelp/hcl section 3 l 4 steel pickling.htm... 

In order to estimate emissions from pickling facilities, U.S. EPA developed 17 model plants to represent five types of pickling operations and one acid regeneration process.12 The model plants include one or more size variation for each process model. The model plants were developed from information obtained from a survey of steel pickling operations and control technologies. U.S. EPA estimated emission rates for model facilities. Using these emission rates and the production and hours of operation for the model pickling plants, emission factors were calculated. These appear in Table 28.12. 

Annual Emission Estimates from Steel Pickling Operations... 

A National Emission Standard for Hazardous Air Pollutants (NESHAP) for new and existing hydrochloric acid process steel pickling lines and HC1 regeneration plants pursuant to Section 112 of the Clean Air Act as amended in November 1990 has been proposed (62 FR 49051, September 18,1997). The purpose of this rulemaking is to reduce emissions of HC1 by about 8360 megagrams per year. 

F-S [Ferrous sulfate] A process for removing ammonia, hydrogen sulfide, and hydrogen cyanide from coke-oven gas by scrubbing with aqueous ferrous sulfate solution obtained from steel pickling. A complex series of reactions in various parts of the absorption tower yield ammonium sulfate crystals and hydrogen sulfide (for conversion to sulfur or sulfuric acid) as the end products. Developed in Germany by F. J. Collin A.G. 

Ruthner A process for recovering hydrochloric acid and iron oxide from steel pickling liquors. Invented in 1968 by A. Hake and P. Borsody at Ruthner Industrieplanungs, Vienna. See also Dravo-Ruthner. 

High ceiling diuretics, 5 169 High chrome-nickel stainless steels, pickling, 16 223... 

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