Ferrous producing

Fenton s reagent. To a solution of tartaric acid or a tartrate add 1 drop of freshly prepared ferrous sulphate solution, i drop of hydrogen peroxide solution and then excess of NaOH solution an intense violet coloration is produced, due to the ferric salt of dihydroxyfumaric acid, HOOC C(OH) C(OH)COOH. 

Upon boiling the alkaline ferrous salt solution, some ferric ions are inevitably produced by the action of the air upon the addition of dilute siilphurio acid, thus dissolving the ferrous and ferric hydroxides, the ferrocyanides reacts with the ferric salt producing ferric ferrocyanide (Prussian blue) ... 

Another reducing titrant is ferrous ammonium sulfate, Fe(NH4)2(S04)2 6H2O, in which iron is present in the +2 oxidation state. Solutions of Fe + are normally very susceptible to air oxidation, but when prepared in 0.5 M 1T2S04 the solution may remain stable for as long as a month. Periodic restandardization with K2Cr20y is advisable. The titrant can be used in either a direct titration in which the Fe + is oxidized to Fe +, or an excess of the solution can be added and the quantity of Fe + produced determined by a back titration using a standard solution of Ce + or... 

When processing municipal solid wastes, an eddy current separation unit is often used to separate aluminum and other nonferrous metals from the waste stream. This is done after removal of the ferrous metals (see Fig. 1). The eddy current separator produces an electromagnetic field through which the waste passes. The nonferrous metals produce currents having a magnetic moment that is phased to repel the moment of the appHed magnetic field. This repulsion causes the nonferrous metals to be thrown out of the process stream away from nonmetallic objects (13). 

Make acid yields coumaUc acid when treated with fuming sulfuric acid (19). Similar treatment of malic acid in the presence of phenol and substituted phenols is a facile method of synthesi2ing coumarins that are substituted in the aromatic nucleus (20,21) (see Coumarin). Similar reactions take place with thiophenol and substituted thiophenols, yielding, among other compounds, a red dye (22) (see Dyes and dye intermediates). Oxidation of an aqueous solution of malic acid with hydrogen peroxide (qv) cataly2ed by ferrous ions yields oxalacetic acid (23). If this oxidation is performed in the presence of chromium, ferric, or titanium ions, or mixtures of these, the product is tartaric acid (24). Chlorals react with malic acid in the presence of sulfuric acid or other acidic catalysts to produce 4-ketodioxolones (25,26). 

As can be seen in Figure 8, the proportion of world pig iron produced in the United States has decreased dramatically since 1950. Also notable is the widening gap between pig iron and steel production, indicating the increasing use of recycled iron or scrap (see Recycling, ferrous metals) and alternative iron sources such as DRI and HBI. The increased demand for scrap is reflected in scrap iron prices (Fig. 9), which in turn have spurred growth in direct reduction processes. 

Acidic Properties. As a typical acid, it reacts readily with alkaUes, basic oxides, and carbonates to form salts. The largest iadustrial appHcation of nitric acid is the reaction with ammonia to produce ammonium nitrate. However, because of its oxidising nature, nitric acid does not always behave as a typical acid. Bases having metallic radicals ia a reduced state (eg, ferrous and staimous hydroxide becoming ferric and stannic salts) are oxidized by nitric acid. Except for magnesium and manganese ia very dilute acid, nitric acid does not Hberate hydrogen upon reaction with metals. 

Hydroxjiamine is used as a substitute for the ferrous sulfamate (26). These systems are called salt-free flow sheets. The main purpose is to ease the problems associated with the processing and storage of the Hquid waste streams (27). Another approach is to use an electropulse column to electrolyticaHy produce to reduce Pu to Pu on a continuous basis (28,29). The half reactions for the flow sheets are... 

Various methods of home-dyeing cotton and wool materials using natural dyes made from hulls of butternut, hickory nut, pecan, eastern black walnut, and Knglish walnut have been described (149). As far back as during the Civil War, butternut hulls have been used to furnish the yellow dye for uniforms of the Confederate troops. More recent attempts have been made to manufacture yellow and brown dyes from filbert shells on a commercial scale. The hulls are treated with copper sulfate and concentrated nitric acid to produce a yellow color, with ferrous sulfate to produce oHve-green, or with ammonia to produce mby-red (150) (see Dyes AND DYE INTERMEDIATES Dyes, natural). 

Iron oxide yellows can also be produced by the direct hydrolysis of various ferric solutions with alkahes such as NaOH, Ca(OH)2, and NH. To make this process economical, ferric solutions are prepared by the oxidation of ferrous salts, eg, ferrous chloride and sulfate, that are available as waste from metallurgical operations. The produced precipitate is washed, separated by sedimentation, and dried at about 120°C. Pigments prepared by this method have lower coverage, and because of their high surface area have a high oil absorption. 

Cyanide iron blues can be prepared by several methods. The most common one is the indirect, two-step process. In the first step, a white precipitate (Berlin white), is produced by the reaction of sodium, potassium, or ammonium ferrocyanide and ferrous sulfate ... 

The PGM concentrate is attacked with aqua regia to dissolve gold, platinum, and palladium. The more insoluble metals, iridium, rhodium, mthenium, and osmium remain as a residue. Gold is recovered from the aqua regia solution either by reduction to the metallic form with ferrous salts or by solvent-extraction methods. The solution is then treated with ammonium chloride to produce a precipitate of ammonium hexachloroplatinate(IV),... 

Primary consumers for ferrous scrap are the iron and steel mills and foundries. Minor consumers iaclude ferroalloy producers, copper producers for use ia copper precipitation (see Recycling, nonferrous metals), and the chemical iadustry. The steel iadustry consumes about three-fourths of the total. Scrap consumption for ferroalloy production, copper precipitation, and the chemical iadustry total less than one million t. The United States is the leading exporter of ferrous scrap, exporting almost nine million t ia 1994, valued at about 1.3 biUioa. Total value of domestic scrap purchases and exports ia 1994 was 8 biUioa (2). 

A comprehensive history of ferrous scrap recycling ia the United States beginning ia 1646 has beea pubUshed (3). Some selected eveats of iaterest iaclude the first opea-hearth steel produced (1868) the first commercial direct-arc electric furnace steel produced ia the United States (1906) the first large iaduction furnace iastaHed ia the United States (1914) the first basic oxygen steel produced ia the United States (1954) the rise of continuous casters and scrap-based minimills (1965) the first thin-slab continuous caster at a minimill (1989) U.S. exports and imports of ferrous scrap at record highs (1990) and the end of production of open-hearth steel (1991). 

The avadabihty of prompt iadustrial scrap is directiy related to the level of iadustrial activity. Producers geaeraHy do aot accumulate prompt iadustrial scrap because of storage requiremeats and iaventory control costs. Thus, it is rapidly available to the scrap consumer or the ferrous scrap iadustry. Prompt iadustrial scrap comes from imported steel as well as domestic steel mill products. Obsolete scrap, also known as old or post-coasumer scrap, is widely used. Treads ia aew steelmaking capacity and the reduced proportions of premium scrap iadicate that use of obsolete scrap should be expected to iacrease. 

NKK s Bio-SR process is another iron-based redox process which instead of chelates, uses Thiobacillusferroidans )2iQ. - 2i to regenerate the solution (9). This process absorbs hydrogen sulfide from a gas stream into a ferric sulfate solution. The solution reacts with the hydrogen sulfide to produce elemental sulfur and ferrous sulfate. The sulfur is separated via mechanical means, such as filtering. The solution is regenerated to the active ferric form by the bacteria. 

Bromide ndIodide. The spectrophotometric determination of trace bromide concentration is based on the bromide catalysis of iodine oxidation to iodate by permanganate in acidic solution. Iodide can also be measured spectrophotometricaHy by selective oxidation to iodine by potassium peroxymonosulfate (KHSO ). The iodine reacts with colorless leucocrystal violet to produce the highly colored leucocrystal violet dye. Greater than 200 mg/L of chloride interferes with the color development. Trace concentrations of iodide are determined by its abiUty to cataly2e ceric ion reduction by arsenous acid. The reduction reaction is stopped at a specific time by the addition of ferrous ammonium sulfate. The ferrous ion is oxidi2ed to ferric ion, which then reacts with thiocyanate to produce a deep red complex. 

The ferrous hydroxide then combines with oxygen and water to produce ferric hydroxide, Fe(OH)2, which becomes common iron mst when dehydrated to Fe202. 

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