Chrome alum

I947) 294 3)Kirk Othmer 1 (1947), 655 4)Cond Chem Dict(1956), 52 Potassium-Chrome Alum(Chrome Alum),... 

ALUM (see Alum, ammonia Alum, chrome, potassium Alum, potassium and Aluminum sulfate) ALUM, AMMONIA... 

Cauttorr. Wear gloves and a mask when working with the powder, and use ventilation. CHROME ALUM (see Alum, Chrome)... 

SYNS CHROME ALUM CHROME POTASH ALUM CHROMIC POTASSIUM SULFATE CHROMIC POTASSIUM SULPHATE CHROMIUM POTASSIUM SULFATE (1 1 2) CHROMIUM POTASSIUM SULPHATE CRYSTAL CHROME ALUM POTASSIUM CHROMIC SULPHATE POTASSIUM CHROMIUM ALUM POTASSIUM DISULPHATOCHROMATE(III) SULFURIC ACID, CHROMIUM (3+) POTASSIUM SALT (2 1 1)... 

Gypsum barite blue vitriol Epsom salt alum ammonium alum chrome alum other sulfates. 

Potassium Chromium Alum, Chrome Alum, KjSOj. Cr2(S04)3.24H20, first isolated by Mussin-Pusehin, is obtained by the reduction of a mixture of potassium dichromate and sulphuric acid by sulphurous acid, alcohol, oxalic acid, etc. ... 

Basicity chrome alum CCRIS 7532 Chrome alum Chrome potash alum Chromic potassium sulfate Chromic potassium sulphate Chromium potassium bis(sulphate) Chromium potassium sulfate (1 1 2) Chromium potassium sulfate (CrK(S04)2) Chromium potassium sulphate Chromium(lll) potassium sulfate Crystal Chrome Alum EINECS 233401-6 Potassium chromic sulfate Potassium chromic sulphate Potassium chromium alum Potassium chromium disulfate (KCr(S04)2) Potassium disulphatochromate (III) Sulfuric acid, chromium(3 ) potassium salt (2 1 1). Mordant for dyeing fabrics uniformly [dodecahydratej mp = 89° d = 1.83 soluble in 4 parts H2O. 

But the admirable researches of Gay-Lussac and of Mitscherlich have established the fact, that in many instances, different compounds assume the same form. Thus, the following substances, and many others, take the form of the cube, tetrahedron, or regular octohedron, which are geometrically connected. Chloride of sodium (sea-salt), chloride of potassium, sal ammoniac bromide of potassium iodide of potassium sulphuret of lead fluoride of calcium bisnlphuret of iron arseniuret of cobalt sulphate of alumina and potash (alum) ammonia alum chrome alum, iron alum sesqnioxide of iron, sesquioxide of aluminum, sesquioxide of chromium. In like manner, other crystalline forms are found to be common to many different compounds, although none occurs so frequently as the cube and its congeners. 

Now if we substitute ammonium for potassium, we have AmO, SO3 + AI3O3, 3SOj + 24HO and this is the formula of ammonia alum. Chrome alum is... 

Manuf./Distrib. Atomergic Chemetals http //www.atomergic.com, Nichem Chromium potassium sulfate CAS 10141-00-1 7788-99-0 (dodecahydrate) Synonyms Chrome alum Chrome potash alum Chromic potassium sulfate Chromium potassium sulfate (1 1 2) Chromium (III) potassium sulfate... 

Alum, chrome (see Chromium potassium sulfate) Alum, potassium (see Aluminum potassium sulfate) Alum, sodium (see Aluminum sodium sulfate)... 

The dichromate ion oxidises iron(II) to iron(III), sulphite to sulphate ion, iodide ion to iodine and arsenic(III) to arsenic(V) (arsenate). Reduction of dichromate by sulphite can be used to prepare chrome alum, since, if sulphur dioxide is passed into potassium dichromate acidified with sulphuric acid, potassium and chromium(III) ions formed are in the correct ratio to form the alum, which appears on crystallisation ... 

Chrome alum is also obtained if the acidified dichromate is boiled with ethanol, the ethanal formed distilling off. 

All compounds of chromium are colored the most important are the chromates of sodium and potassium and the dichromates and the potassium and ammonium chrome alums. The dichromates are used as oxidizing agents in quantitative analysis, also in tanning leather. 

CsAl(SO 2 -12H20 iron alum [13463-29-1], KFe(SO12Rp- chrome alum [7788-99-0], KCr(SOimp- and chromoselenic alum [17855-06-0],... 

Sodium thiosulfate is still used in chrome leather tanning as a reducing agent in two-bath processes to reduce dichromate (hexavalent chromium) to chrome alum (trivalent chromium) (see Leather). 

Chrome Alum Electrolysis. In the chrome alum process (Fig. 2) typified by the 2000 tons per year Flkem Metals Co. plant at Marietta,... 

Ohio, high carbon ferrochromium is leached with a hot solution of reduced anolyte plus chrome alum mother Hquor and makeup sulfuric acid. The slurry is then cooled to 80°C by the addition of cold mother Hquor from the ferrous ammonium sulfate circuit, and the undissolved soHds, mostiy siHca, are separated by filtration. The chromium in the filtrate is then converted to the nonalum form by conditioning treatment for several hours at elevated temperature. 

Fig. 2. Flow sheet for production of electrolytic chromium by the chrome alum process at the Marietta Plant, Flkem Metals Co., Marietta, Ohio.

The mother Hquor from the cmde ferrous sulfate crystallisation contains neady all the chromium. It is clarified and aged with agitation at 30°C for a considerable period to reverse the reactions of the conditioning step. Hydrolysis reactions are being reversed therefore, the pH increases. Also, sulfate ions are released from complexes and the chromium is converted largely to the hexaaquo ion. Ammonium chrome alum then precipitates as a fine crystal slurry. It is filtered and washed and the filtrate sent to the leach circuit the chrome alum is dissolved in hot water, and the solution is used as cell feed. 

Fig. 3. Principal electrolytic ceU reactions and electrolyte concentrations in chromium production by the chrome alum process.

Table 5. Solution Concentrations in Electrolysis of Chrome Alum, g/L...

Table 6. Operating Parameters for Electrowinning of Chromium from Chrome Alum...

The metal obtained by this process contains less iron and oxygen than that from the chrome alum electrolyte. The gas content is 0.02 wt % O, 0.0025 wt % N, and 0.009 wt % H. If desired, the hydrogen content can be lowered still further by a dehydrogenation treatment. 

Specification Chrome alum Basic chrome chloride Chrome acetate... 

The reaction is cataly2ed by all but the weakest acids. In the dehydration of ethanol over heterogeneous catalysts, such as alumina (342—346), ether is the main product below 260°C at higher temperatures both ether and ethylene are produced. Other catalysts used include siUca—alumina (347,348), copper sulfate, tin chloride, manganous chloride, aluminum chloride, chrome alum, and chromium sulfate (349,350). 

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