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.

Method for reducing trace element lead in sodium dichromate and chromic anhydride products

Abstract: The invention discloses a method for reducing trace element lead in sodium dichromate and chromic anhydride products. The method includes the steps as follows: taking sodium chromate neutral solution in the production of calcium-free roasted sodium dichromate; adding lead acetate or lead seed crystal which accounts for 0.02%-0.1% sodium chromate neutral solution in mass until the lead content in the solution reaches 300ppm-500ppm; adjusting the pH value to 8-10 by sodium hydroxide solution with mass percent concentration of 30%; adding a heavy metal precipitation flocculant; and reducing the lead content in the sodium chromate neutral solution below 2ppm after the processes of heat insulation, aging, filtration and the like, so as to achieve the purpose of reducing the lead content in the sodium dichromate and the chromic anhydride products. Lead flocculant precipitates are generated, and the lead flocculant precipitates can serve as lead seed crystals to use continuously after being washed by water and treated with hydrochloric acid.

Method of preparing liquid self-hardening mixtures

Abstract: 1293837 Foundry mould compositions VSESOJUZNY PROEKTNO - KONSTRUKTORSKO - TEKHNOLOGICHESKY INSTITUT STROIDORMASH 4 Dec 1970 57786/70 Heading C3N A method of preparing a liquid self-hardening mixture for making casting moulds and cores comprises mixing together: (i) a filler; (ii) a binder comprising at least one salt of lignosulphonic acid (sulphite lye); (iii) a foaming agent; (iv) a solidifying agent comprising a hexavalent chromium compound or a persulphate; (v) at least one water-soluble inorganic compound of copper, iron or aluminium; and (vi) water. The hexavalent chromium compound may be chromic acid anhydride or sodium dichromate whilst the persulphate may be ammonium persulphate. Component (v) may be copper sulphate, ferric chloride or aluminium chloride and the foaming agent may be an alkylaryl sulphonate. The filler may be quartz sand optionally together with a minor proportion of refractory clay. Preferably the components are taken in the parts by weight quartz sand 92-100, refractory clay 8-0; binder containing salts oflignosulphonic acid (45-55% by weight aqueous solution) 1A5-8A0; foaming agent 0A1-6; solidifying agent 0A1-1A5; watersoluble inorganic compound 0A1-2A0; and additional water 0-5A0.

Preventive and remedy for steroid cataract

Abstract: PURPOSE:The titled remedy that contains 1-hydroxy-5-oxo-5H-pyrido[3,2-a]phen oxazine-3-carboxylic acid or its salt CONSTITUTION:A preventive or remedy for setroidal cataract is obtained by using 1-hydroxy-5-oxo-5H-pyrido[3,2-a]phenoxazine-3-carboxylic acid or its salt The above-stated effective ingredient is obtained by adding conc sulfuric acid to an aqueous solution of 4,5,6,8-tetrahydroxyquinoline-2-carboxylic acid and adding drowise saturated potassium ferricyanate or sodium dichromate to form 4,6-dihydroxyquinoline-2-carboxylic acid, dissolving the product and o-aminophenol in acetic acid and concentrating the mixture under reduced pressure The drug may be orally or parenterally administered, but is the most effective, when it is given in the form of eye drop (1-2 drops a 1 application, 5 applications a day)

Method for preparing sodium dichromate through ultrasonic-microwave combination

Abstract: The invention relates to a method for preparing sodium dichromate through ultrasonic-microwave combination and belongs to the technical field of chromium salt production. The method comprises steps as follows: firstly, chrome iron ore is crushed and ground until particle size is 200 meshes or lower, sodium carbonate is added and mixed with obtained powder uniformly, under the microwave power being 1500 W, a mixture is subjected to microwave heating to reach 400-450 DEG C, the temperature is kept for 30-60 min, and the mixture is naturally cooled to the room temperature after constant-temperature treatment and is ground into a powdery material; distilled water is added to the powdery material, a mixture is subjected to leaching under the ultrasonic condition and subjected to suction filtration after leaching, and a ferric oxide solid impurity and a leachate are separated out; dilute H2SO4 is added to the obtained leachate until pH is 7-8, filtration and separation are performed again to remove an aluminium hydroxide solid impurity, dilute H2SO4 is added to a leachate obtained through refiltering until pH is lower than 5, a mixed solution is evaporated, concentrated, cooled and filtered, a product is washed and dried, and sodium dichromate can be obtained. The invention aims to reduce reaction temperature, increase conversion rate of chromium and reduce technological process.