Sodium dichromate

About: Sodium dichromate is a research topic. Over the lifetime, 421 publications have been published within this topic receiving 6202 citations. The topic is also known as: Disodium salt & sodium bichromate.

Process for the production of sodium dichromate

Abstract: The invention relates to a process for the production of sodium dichromate and sodium dichromate solutions by oxidative roasting of chrome ores under alkaline conditions, leaching of the furnace clinker obtained with water or an aqueous chromate-containing solution, adjustment of the pH to from 7 to 95, removal of the insoluble constituents by filtration, a sodium monochromate solution being obtained, conversion of the monochromate ions of this solution into dichromate ions by acidification and crystallization of sodium dichromate by concentration of this solution, characterized in that the acidification is carried out with carbon dioxide under pressure with removal of sodium hydrogen carbonate, the remaining solution is then very largely freed from sodium monochromate by cooling to a temperature below 10° C and filtration, any monochromate ions still present in the remaining solution are converted into dichromate ions by addition of an acid and the sodium monochromate filtered off is added to the sodium monochromate solution before conversion with carbon dioxide into a sodium dichromate solution

Textile fiber drafting element and method of making same

Abstract: A textile fibre drafting element, e.g. a drafting apron, spinning roll or roll cover, has a surface of a rubber-like conjugated diene polymer or copolymer which has been modified by reaction with an aqueous solution of sulphuric acid containing dichromate ions, the concentration of the sulphuric acid being at least 1 per cent. but not sufficient to effect substantial deterioration of the rubber-like material, and its dichromate ion concentration being at least 0.01 mol. per litre. The treatment may be carried out before or, preferably, after vulcanization. Specified rubber-like materials, are polychloroprene, polyisoprene, polybutadiene, and copolymers of butadiene with styrene, acrylonitrile or acrylic esters. Specified dichromate ion substances are potassium dichromate, ammonium dichromate and sodium dichromate. It is preferred that the aqueous solution contains 1 to 25 per cent. sulphuric acid and from 0.01 to 0.5 mols. per litre of dichromate ion. Specification 643,666 is referred to.

Silica Sulfuric Acid/Sodium Dichromate Dihydrate as an Efficient Heterogeneous Method for the Oxidation of Alcohols Under Mild Conditions

Abstract: A combination of silica sulfuric acid and sodium dichromate dihydrate in the presence of wet SiO 2 were used as an effective oxidizing agent for the oxidation of alcohols to their corresponding aldehyde or ketone derivatives in dichloromethane or toluene with excellent yields.

Corrosion-inhibiting pigments, their production and use

Abstract: The invention relates to corrosion-inhibiting pigments containing metallic oxides, phosphates and/or molybdates, wherein the metals are zinc, aluminum, iron, barium, strontium, calcium, magnesium and titanium, singly or in combination, wherein the pigments also contain 0.03-2% by weight of soluble sodium dichromate or equivalent amounts of potassium dichromate, ammonium dichromate or equivalent amounts of respective chromates or chromic acid, singly or in their mixture. The invention also relates to a process for the manufacture of the pigments by thorough homogenization of the chromate components with the pigments, and to the use of the pigments in primers for ferrous and non-ferrous metallic substrates.