What are refractory minerals?
Refractory minerals can be defined as minerals or synthetic inorganic crystal phases that have high melting points. They should also be resistant to deformation and to softening at high temperatures. Refractories are usually classified as acid, basic, or other.
What are the types of refractory materials?
The typical refractory materials include fireclay refractories, high alumina refractories, silica brick, Magnesite refractories, Chromite refractories, Zirconia refractories, Insulating materials and Monolithic refractory.
How many types of refractory are there?
Refractory materials are classified into three types based on fusion temperature (melting point).
What is the purpose of refractory?
Refractory parts are generally found in the combustion and post combustion chambers/zones of a biomass or biogas boiler. The main purpose of refractory material is to contain the heat generated by combustion, the material has a high melting point that maintains it’s structure at very high temperatures.
What is refractory work?
Refractory jobs involve working with refractory materials and equipment, such as a furnace, broiler, and kiln. A refractory bricklayer or refractory mason also works to build ovens and other structures for containing heated materials such as molten metal. Masons bond bricks or other equipment with specialized mortar.
What is refractories and classification?
Refractories are classified according to their physical form. These are the shaped and unshaped refractories. The shaped is commonly known as refractory bricks and the unshaped as monolithic refractories. Brick shapes are usually divided into two types (i) standard shapes and (ii) special shapes.
What is the best refractory material?
5.15 Thermal Behavior Magnesium oxide has the highest coefficient of expansion of the refractory materials commonly used. Silicon carbide has a comparatively low coefficient of expansion and fused or vitreous silica has the lowest expansion of all the refractory materials commonly used.
Which is a basic refractory?
The basic refractory materials include alumina, silica, magnesia and lime.
What does refractory mean in medical terms?
(reh-FRAK-tor-ee) In medicine, describes a disease or condition that does not respond to treatment.
Which is an example of a refractory oxide?
A refractory oxide layer is chosen as the outermost layer, due to the compatibility of the oxide with the oxygen in the environment. Examples of the refractory oxide are hafnium oxide (HfO 2) with a melting temperature 2758°C, and yttrium oxide (Y 2 O 3) with a melting temperature of 2425°C.
What makes a silica refractorie an acidic refractory?
At high temperatures, acidic refractories may also react with limes and basic oxides. Silica refractories are refractories containing more than 93% silicon oxide (SiO 2 ). They are acidic, have high resistance to thermal shock, flux and slag resistance, and high spalling resistance.
Is the cost of refractory oxide going down?
Longer campaigns justify a disproportionately higher investment in refractories as proven by the result that the costs of refractories per ton of iron and steel produced have been steadily declining since the early 1980s.
What kind of materials can be used in refractory conditions?
Silicon carbide and carbon ( graphite) are two other refractory materials used in some very severe temperature conditions, but they cannot be used in contact with oxygen, as they would oxidize and burn. Binary compounds such as tungsten carbide or boron nitride can be very refractory.
