Glass calcium sodium silicate

Phase Diagram Calcium silicates are the most important constituents of hydraulic Portland cements (see Chapter 5), as well as of basic and acidic blast furnace slags and stabilized refractories based on dolomite they also occur as devitrification products of some technical CNS (calcium sodium silicate) glasses. The phase diagram is complicated, as shown in Figure 3.24. 

The compound occurs in nature as the mineral, berlinite. Also, it occurs in nature in minerals, amblygonite, [NaAl(P04)(0H)j augelite, [Al2(P04)(0H)3] lazulite, [(Mg,Fe)Al2(P04)2(0H)2] variscite [(Al,Fe3+)(P04) 2H20] andwavel-lite, [Al3(0H)3 (P04)2 5H20]. It is used as flux for ceramics as cement in combination with calcium sulfate and sodium silicate and in the manufacture of special glasses. It is also used in dried gel and therapeutically as an antacid. 

AIPO4 is isoelectronic with silica and, as such, readily forms glasses and Si02-like crystalline materials. As well, framework stmctmes similar to zeolites may be prepared by the use of amines as templates. Like zeolites, these are active in catalytic reactions such as methanol conversion to hydrocarbons (seeZeolites) As a ceramic material, AIPO4 is an infusible material that is insoluble in water but is soluble in alkali hydroxides. It is often used with calcium sulfate and sodium silicate for dental cements. AIPO4 is also used as a white pigment that also acts as a corrosion inhibitor. 

Sand, 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... 

The raw materials are blended and charged into the glass furnace, which is a refractory lined bath covered by a refractory roof. The furnace is heated to about 2000 °C by burners in the space above the molten glass. As the raw materials enter the bath, the carbonates decompose and evolve carbon dioxide, which helps to agitate the bath and to disperse the solids in the melt. The solids react to produce the sodium/calcium/magnesium silicate which is the principle constituent of most glasses. 

From this we concluded that the replaced feldspar preparation was mostly a method for preparing hydrous silica containing a little alumina but substantially free of other metallic ions due to the extensive acid treatment to remove the alkali and calcium ions. We also concluded that purified silica hydrogel could be made less expensively from water glass (sodium silicate). 

Glass is an amorphous material. In such a substance, submicroscopic units are randomly oriented relative to one another. This is distinguished from a crystal, in which submicroscopic units arc arranged in a periodic and orderly fiishion (Section 6.3). Glajss can have a variety of chemical composition-s. Common glass is a mixture of sodium silicate, NajSiO, and calcium silicate, CaSi03. It is formed by heating a blend of sodium carbonate, calcium carbonate, and silica ... 

Many methods were used to eliminate collapsibility in the research process of collapsible loess. Silicified method is one of the ways. It uses water glass (sodium silicate) as main agent solution which was injected into loess under pressing, generates cementations material after action of earth calcium... 

Precipitated silicas and silicates have widespread applications in rubber. They have two distinct functions in rubber (1) as a reinforcing filler and (2) as an integral part of proprietary bonding systems. The products are produced by precipitation from sodium silicate (water glass) by reaction with acids. Replacement of the acid, in part or in total, by metal salts (of calcium or aluminium) results in the production of metal silicates. Because of the purity of the water glass used, the products are free from contaminants. The precipitate is filtered and dried using a variety of techniques. 

Basic copper(ll) carbonate Cobalt(ll) stannate Cobalt(ll)-doped alumina glass Calcium copper(ll) silicate Sulfur radical anions in a sodium aluminosilicate matrix Barium manganate(VII) sulfete Copper(ll) phthalocyanine Basic oopper(ll) sulfete Iron(lll) hexacyanoferrate(ll) Cobalt(ll) silicate Basic copper(ll)... 

Ordinary sodium silicate and calcium silicate are, in fact, metasilicates. Sodium silicate may be made by heating sodium carbonate, Na2C03, with pure sand, Si02, in a furnace to form a glass. Window glass (soda glass) is made by a continuous process in which sand reacts at 1 400 °C with fused carbonates of sodium, potassium and calcium (limestone and some sodium sulfate). At these temperatures the carbonates behave as a mixture of the oxide and carbon dioxide gas (for instance, CaO + CO2). The liquid is stirred by the evolution of CO2, H2O (from the hydrated salts) and SO3. 

---