Glass raw materials

The selection criteria for raw materials for glass manufacture are particularly influenced by the purity required for the application, availability, potential for undesirable emissions and cost. Since in the case of the main ingredient in glass production, sand, the transport costs considerably exceed the actual cost, it should generally be available nearby. 

preferably fine particulate, is used as the source of Si02 in the manufacture of silicate glasses. Raw materials for the standard network-modifiers are lime, dolomite (CaC03 MgC03) for the alkaline earth oxides, sodium carbonate for sodium oxide, feldspar (sodium potassium calcium aluminum silicate), or other naturally occurring aluminum silicates, for aluminum oxide. Boron is used in the form of boric acid, borax and other boron minerals, e.g. ulexite (NaCa[B505(0H)6] 5H2O) or colemanite 

Main utilization sectors for recycled glass container glass, mineral insulation fibers 

Quality of glass depends on the efficiency of raw material mixing 

Undesirable coloring through iron-content of the batch. Maximum permissible Fe20j-content for flat glass 0.10% 

---

The main source of silica in antiquity, as today, was sand and, very occasionally, crushed rock or pebbles. The most common modifier was soda, which was obtained from natron lakes, as in ancient Egypt, for example, or from vegetable ash. Most lime was derived from limestone, although some lime could also enter the mixture of glass raw materials together with soda... 

KotSmId F., Glass Raw-Materials (in Czech), SNTL, Prague, 1971 (Sklafske suroviny, SNTL, Praha). 

Uses Clarifying agent in glass prod. glass raw material defoliant for cotton reducing agent Manuf./Distrib. Allpro Wm. Blythe Ltd http //www. wm-blythe. co. uk... 

Uses Specialty glass raw material for tinting glass reducing agent intermediate in prep, of stannous salts used in pharmaceuticals soft abrasive... 

For the future prospect, we would improve the DFC burner for the continuous flow process and apply to heat other powdered material as well as the glass raw material. 

Modem analytical techniques have not only aided glass producers, but also enabled suppUers of raw materials to produce a more consistent product. Closer monitoring of purity and on-site blending of raw materials are now used by many producers. A stable and uniform raw material is the key to the manufacture of high quaUty glass. 

---