Glass forming float process

Glass manufacturers use hydrogen as a protective atmosphere in a process whereby molten glass is floated on a surface of molten tin. As the glass hardens, it forms a much smoother surface than is attainable by other production techniques. Hydrogen is used as an atmosphere to prevent the oxidation of molten tin. In the working of leaded glass,... 

Plate glass Glass formed by the float glass process. See Glass, plate. 

In the float process a glass melt is poured continuously from a furnace onto the surface of molten tin, where it floats because of the density difference. The floated glass melt spreads to form a ribbon with a defined thickness and... 

The difference between macroscopic and microscopic objects is clear from everyday experience. For example, a glass marble will sink rapidly in water however, if we grind it into snb-micron-sized particles, these will float or disperse freely in water, prodncing a visibly clondy soln-tion , which can remain stable for honrs or days. In this process we have, in fact, prodnced a colloidal dispersion or solution. This dispersion of one (finely divided or microscopic) phase in another is quite different from the molecular mixtures or true solutions formed when we dissolve ethanol or common salt in water. Microscopic particles of one phase dispersed in another are generally called colloidal solutions or dispersions. Both nature and industry have found many uses for this type of solution. We will see later that the properties of colloidal solu-... 

Ions of precipitate particles are adsorbed or attached at the surface of bubbles rising through a liquid, and are thereby separated. A substance which is not surface-active itself can be made so through union with, or adherence to, a surface-active agent (surfactant). Froth flotation involves separation (pre-concentration) by frothing. If an insoluble product is formed in interaction between the ion to be separated and a surfactant, the process is called ion flotation. If the ion is first precipitated and the precipitate is then floated with or without the addition of a surfactant, the process is called precipitate flotation. Flotation is accomplished in a special cylindrical vessel provided with a sintered glass disk at the bottom to break the gas (nitrogen, air) stream into small bubbles [92]. 

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