Forsterite

After firing, the bricks are checked for stabilization. This is done by keeping the fired brick in boiling water for 24 h. If the brick is not changed by this treatment, then it is stabilized. 

A cheaper variety of dolomite brick is known as semi-stabilized dolomite. This is prepared from the calcined dolomite without the separate addition of silica. Fe203 and AI2O3 are added to the calcined dolomite for bonding purposes. Heavy oils are also added that uniformly spread the Fe203 and AI2O3 particles in the mixture. These oils also keep out moisture. Thus, a reaction between moisture and calcia is prevented until the bricks are fired. The firing is done is a kiln at a temperature of 1400°C. If the fired bricks are not put into service immediately, they are coated with a tarry material. 

Forsterite is magnesium silicate. The origin of this refractory is olivenes. On decomposition, olivenes gives rise to serpentine, talc, and steatite. All these minerals are used to make forsterite bricks. The magnesia content in the bond is increased by adding very fine MgO. The mixture is then dry-pressed to make the brick. The green bricks are then fired. 

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Forsterite. Pure forsterite is rare in nature. Most natural magnesium orthosiUcates form soHd solutions of fayaUte, Fe2Si04, and forsterite. Forsterite refractories are usually made by calcining magnesium siUcate rock such as dunite, serpentine, or oHvine with sufficient magnesia added to convert all excess siUca to forsterite and all sesquioxides to magnesia spinels. 

Temp, °C Fkeday SiHca Brick Magnesite Chrome Forsterite MulHte Cristobahte Peridase Comndum... 

Refractory Magnesite, 92% MgO Magnesite—chrome, CB CB Fired Forsterite, stabih2ed Chrome, fired 90% 70%... 

Forsterite Refractories. Refractories made from forsterite, Mg2Si04, resist alkah attack and have good volume stabiUty, high temperature strength, and fak 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. 

Chrysotile (serpentine) occurs in both clino and ortho stmctures. Both one-layer ortho and clino, and six-layer ortho (as in nacrite) stmctures have been observed. Chrysotile transforms at high temperature to forsterite [15118-03-3] and siHca. Particularly fibrous varieties are called asbestos (qv). 

Other types of refractory that find use are forsterite, zirconia, and zircon. Acid-resisting bricks consisting of a dense body like stoneware... 

The silicates which will occur are orthosilicates, R++2Si04, metasilicates, R++Si03, etc. This is verified by observation no basic silicates of such cations are known, although many normal silicates such as forsterite Mg2Si04, etc., exist. 

From these vievqjoints, we have developed a femtosecond NIR laser microscope with a home-built cavity dumped chromium forsterite (Cr F) laser as an excitation light source whose output wavelength is centered at 1260 run. In the following the set-up of the NIR laser microscope and its application to multiphoton imaging are presented. 

Confocal Microscope with a Chromium Forsterite Ultrafast Laser as an Excitation Source... 

Other types of refractory that find use are forsterite, zirconia, and zircon. Acid-resisting bricks consisting of a dense body like stoneware are used for lining tanks and conduits in the chemical industry. Carbon blocks are used as linings for the crucibles of blast furnaces, very extensively in a number of countries and to a limited extent in the United States. Fusion-cast bricks of mullite or alumina are largely used to line glass tanks. 

The ammoniacal systems do not cause corrosion problems and this allows use of standard materials of construction. The process is mainly applicable to high iron limonitic laterites. The amount of acceptability of the transition ore (S-ore) is limited due to nickel loss caused by forsterite formation during the roasting process. 

A2Si04-B2Si04 Olivine Mg2Si04-Fe2Si04, end members forsterite and fayalite, sobd solution is olivine... 

Frster-Dewar-Knott (FDK) rule, 20 510 Frster energy transfer, 22 218 Forsterite, as a refractory raw material, 21 490, 518... 

Table 1.5. A mineralogical matrix (mole fractions) for the enstatite-forsterite-quartz assemblage.

Figure 1.4 A reactional assemblage enstatite-forsterite-quartz in the 2-dimensional space Si02-MgO. Enstatite can be decomposed as 3/4 forsterite plus 1/4 quartz.

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