Borax, molten

To produce amorphous anhydrous borax, the molten borax is mn between two large water-cooled roUs, forming sheets about 1.6 mm thick, which ate then cmshed and screened to the desired particle size. Because the borax is cooled rapidly by the roUs, it remains largely amorphous, though it may contain some crystalline anhydrous borax. 

Sihcon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. Chemical reactions do, however, take place between sihcon carbide and a variety of compounds at relatively high temperatures. Sodium sihcate attacks SiC above 1300°C, and SiC reacts with calcium and magnesium oxides above 1000°C and with copper oxide at 800°C to form the metal sihcide. Sihcon carbide decomposes in fused alkahes such as potassium chromate or sodium chromate and in fused borax or cryohte, and reacts with carbon dioxide, hydrogen, ak, and steam. Sihcon carbide, resistant to chlorine below 700°C, reacts to form carbon and sihcon tetrachloride at high temperature. SiC dissociates in molten kon and the sihcon reacts with oxides present in the melt, a reaction of use in the metallurgy of kon and steel (qv). The dense, self-bonded type of SiC has good resistance to aluminum up to about 800°C, to bismuth and zinc at 600°C, and to tin up to 400°C a new sihcon nitride-bonded type exhibits improved resistance to cryohte. 

Miller A process for purifying and removing silver from gold by passing chlorine gas through the molten metal, covered with borax. The silver forms silver chloride, which floats to the top. Bismuth, antimony, and arsenic are eliminated as their volatile chlorides. Developed by F. B. Miller at the Sydney Mint in Australia in 1867 and soon in world-wide use. 

Anhydrous horax is made from its hydrated forms by calcination and fusion. In the United States, it is produced by US Borax and Kerr-McGee Corporations. The starting material is horax decahydrate. The amorphos form is obtained by rapid cooling of molten borax. The molten material on long standing produces the crystaUine form. 

Boric oxide is produced by treating borax with sulfuric acid in a fusion furnace. At temperatures above 750°C, the molten boric acid layer separates out from sodium sulfate. It then is decanted, cooled, and obtained in 96-97% purity. Boric acid above 99% purity may be obtained by fusing granular material. 

After being strongly ignited, niobium pentoxide becomes insoluble in all acids other than hydrofluoric acid, but is dissolved by molten potassium hydrogen sulphate, ammonium hydrogen sulphate, and borax. It is also insoluble in solutions of alkalis, but is converted into the alkali niobates by fusion with alkali hydroxides and carbonates. 

This metal is obtained on a commercial scale both by reducing antimony oxide with carbon and by reducing antimony sulphide by means of metallic iron. The second method possesses the advantage that antimony sulphide, a natural product, is used directly and does not need to be first converted into the oxide. The iron sulphide formed by this method is fusible and forms an immiscible layer which floats on top of the molten antimony. The addition of borax facilitates the separation of the liquid layers, and thus the globules of melted antimony are allowed to sink more easily to the bottom of the crucible and form a metallic regulus. The upper layer furthermore covers the surface of the metal and hinders its oxidation and the escape of the volatile Sb203. 

Molten carbonate fuel cell technology was developed based on the work of Bauers and Ehrenberg, Davy tan, and Broers and Ketelaar in the 1940s [8], The electrolyte is a molten salt such as sodium carbonate, borax, or cryolite. This type of fuel cell requires a high temperature to keep the electrolyte in a molten state. The following 30-40 years saw great successes, with the development of MCFCs and MCFC stacks that could be operated for over 5000 hours. 

When platinum is dissolved in a great excess of molten tellurium under borax and the mass allowed to cool slowly, the ditelluride crystallises out in octahedra and may be separated from the excess of tellurium by treatment with cold, dilute nitric acid. 

Miller s dry parting process 3 involves the action of chlorine on molten gold covered with a layer of borax to prevent spurting. The gold is not attacked, but the silver is converted into chloride. When the gold has solidified, the molten silver chloride collected on the surface is run off, carrying with it a small proportion of gold. When silver is the chief... 

The reaction between boron(III) oxide (or boric acid, borax, kernite or colemanite) and phosgene in a molten salt (AlClj/NaCI) has been patented as a commercial route to boron(III) chloride [148] ... 

Sodium tetraborate (Spectroflux 200 , Johnson and Matthey Co.) was tried with much greater success. Disks produced by fusion of 0.5000 g of calcined gypsum and 6.00 g of sodium tetraborate (Table 1) produced absolutely clear and transparent disks with perfect surfaces. The use of a higher specimen to flux ratio was dictated by the lower solubility of anhydrite in molten borax. 

Shen Tsin Nan and Yu.K. Delimarskii, Solubility of Oxides of Titanium, Molybdenum and Tungsten in Molten Borax, Ukr. Khim. Zh. 27 (1961) 454-457. 

We are interested in vanadoborate cluster materials both as precursors to porous solids and as a new class of molecular magnets. We have synthesized a variety of vanadoborate cluster compounds 1-7, primarily by use of two different synthetic routes. The first involves hydrothermal synthesis, using sodium tetraborate ( borax ) as the boron source and the second uses molten boric acid as the reaction medium. In general anionic clusters are found. Herein we report that these have novel electronic and bonding arangements which affect their magnetic behaviour and also that they may be cross-linked together by metal centers such as Cd to form stable microporous phases. 

---