Glasses alkali attack

Fused alkalis attack glass if several preparations are to bo carried out, a copper flask should be used. 

The alkali metal hydroxides are also readily absorb CO2 and H2S to form carbonates (or hydrogencarbonates) and sulfides (or hydrogen-sulfides), and are extensively used to remove mercaptans from petroleum products. Amphoteric oxides such as those of Al, Zn, Sn and Pb react with MOH to form aluminates, zincates, stannates and plumbates, and even SiC>2 (and silicate glasses) are attacked. 

Determination of resistance of Glass to Attack by Boiling Aqueous Solution of Mixed Alkali, ISO R695 1968 ... 

Alkali ions in solution increase the pH, with two consequences. The rate of silica extraction increases with the rise in pH value above 9 and the rate of alkali exchange is reduced. However, since the higher alkalinity favours solution (of silica) further alkali is released by the lattice. The quantity of alkali extracted can be used as a measure of the resistance of glass to attack... 

Forsterite Refractories. Refractories made from forsterite, Mg2Si04, resist alkali attack and have good volume stability, high temperature strength, and fair resistance to basic slags. Uses include nonferrous metal furnace roofs and glass-tank refractories not in contact with the melt, ie, checkers, ports, and uptakes. 

Soft glass Alkali-resistant glass Poor More sensitive than borosilicate Attacked by alkali solutions Boron-fi ee. Trademark Coming... 

This paper described some of the principal wear mechanisms of basic refractories used in glass tank regenerators. Alteration of refractories by V2O5 and depletion of CaO from refractories exposed to sodium sulfate was discussed. Alkali attack on forsterite-bonded basic brick was described. Properties of a new type of forsterite-bonded brick that offers the potential for improved performance were presented. 

Chemical reactions are often increased or decreased by the presence of other components. Alkali attack on glass is thus hindered by certain ions, particularly those... 

Because acid and alkali attacks on glass are fundamentally different, silica-gel layers produced by acid attack obviously are not necessarily effective against alkali solutions and may be destroyed. Conversely, the presence of ions that inhibit alkali attack does not necessarily represent protection against acids and water. The most severe chemical exposure is therefore an alternating treatment with acids and alkaline solutions. As in all chemical reactions, the intensity of the interaction in-... 

Alkali resistant (AR) glass fibres have been developed with a specific formulation that includes a substantial amount of zirconia (Z1O2). The higher the zirconia content, the better the resistance to alkali attack of the fibres. 

Cohen, E. B., Diamond, S. (1975) Validity of flexural strength reduction as an indication of alkali attack on glass in fibre-reinforced cement composites , Proc. RILEM Symp. Fibre-reinforced Cement and Concrete, Sheffield, pp. 315-25. 

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