Another type of brick is lime brick. Sand-lime brick is a type of brick in which water, silica and quicklime (coa) are used. Lime bricks first began to be developed industrially in Germany in 1884, and then England became one of the major producers of this product around the world. Ajr online website (website selling bricks all over Iran) will guide you further byidentifying calcium silicate bricks the specifications and features of this product. In fact, the baking curve of this brick is at a temperature of 1420 to 1480 degrees Celsius, and the linear expansion during baking is equal to 4-5%. In industrial and factory conditions, this brick withstands temperatures up to 1700 degrees Celsius, which is due to the presence of liquid phase in its main ingredients. Types of silica bricks You can buy these products in two different colors. In the market, this product is available in red and brown, which you can buy according to the facade of the structure as well as the climatic environment. Advantages of silica brick The first and most important advantage of using this brick is its very high melting temperature. After that, it can be high pressure resistance, high resistance to acidic environments, resistance to moisture and temperature, and no formation of crusts and cracks on the surface of the brick. This product has a low volumetric weight and high thermal conductivity, and finally, the price of silica firebrick is the next main issue, which, along with all its advantages, has an affordable price. Community Verified icon. 
This product, like all building materials, has disadvantages. One of these things is the low shock resistance of this product. In this way, it is shocked at temperatures less than 500 degrees Celsius, and in alkaline environments, or in case of contact with game slags, it undergoes changes in the physical and chemical texture of the product. Advantages of silica bricks: 1) Cheap raw materials 2) Tolerating relatively high pressures at high temperatures. For example, it can withstand a pressure such as PSI 50 up to its melting point (1710-1730). 3) Good resistance against iron oxides and CaO and generally acidic slags 4) Low shrinkage when used at high temperatures 5) Good abrasion resistance Disadvantages of silica bricks: 1) Low resistance to thermal shock below 600 degrees Celsius 2) Low resistance against game slag and alkalis. Significant standards of silica brick: • Silica refractory brick 97-416 (2007) C • Silica brick 12475-1 Community Verified iconAbove 800 degrees Celsius, the reaction between the free surfaces of quartz and lime begins. For simplicity, this reaction is considered as a dissolution reaction (ie dissolution of quartz in lime) which causes the formation of siliceous-lime glass. With increasing temperature and time, the percentage of silica in this glass increases. The mentioned glass can crystallize and produce cristobalite at a temperature of 1300 degrees Celsius. The use of silica in the production of sand-lime bricks is one of the many uses of this precious mineral, which has led to the production of light and resistant bricks in various colors. The silicas used in these bricks have different sizes and their diameter and particle size are determined according to the type of brick in question. Stay with us to learn more about the reasons for using Crane's silica dioxide in the production of sand-lime brick and its advantages and disadvantages. 
how to make silica bricks
In 1960, the steel industry consumed 3/4 of all silicon refractories produced. Other industries that used these refractories were: glass industry and carbon industry (preparation of coke, etc.). In 1969, the consumption of silicon bricks in the steel industry decreased to 1.3 and that of the carbon industry to 1.4 in 1960. The reason for this reduction in the case of the steel industry was the retirement of steel production by the Siemens-Martin (HO) method and its replacement by the D.L method.In the case of electric arc furnaces that had silicon roofs, it should be noted that these bricks are now being replaced by high alumina bricks. There are other uses, such as making room and tunnel furnaces. But these applications are relatively few. Alkaline refractories are now used in the roof of copper smelting furnaces, which previously used silica refractories. Semi-silica bricks with 88-93% silica are still used and are used in generators and the roof of heat treatment furnaces. Their resistance to thermal shock and volume stability are better than silica bricks and they are cheaper. 
These refractories, which are prepared from a mixture of sand and clay, unlike silica refractories, when in contact with slag, their surface is glazed and prevents the penetration of metal into the refractories. But due to its high thermal conductivity and impermeability against gases, nowadays it is mostly used to cover the inner wall of glass paste production furnaces in glass factories, gas coking furnaces and ceramic furnaces. Silicon oxide is an acidic oxide. Therefore, the chemical resistance of silica brick against acid melts is very good. But vapors and gases containing alkaline compounds cause corrosion of these bricks. The main producing countries of silica bricks are European countries, especially Germany, France, Austria and Spain, and Asian countries such as China, Japan, Korea and India. The main consumer countries of this type of product are France, Germany, Czech Republic, Italy and China. Terms of import and export of silica brick: There is no restriction on the import of this product and due to the fact that it is not produced domestically, it has low import duties. Baking is done at a temperature between 1430-1500 degrees Celsius. This process is done in a tunnel furnace and it takes about 250 hours in total (heating is done with a thermal gradient of 5-10°C). 
The reactions performed in the baking stage of silica bricks: up to a temperature of 750 degrees Celsius, the brick is composed of a mixture of quartz particles in a field of lime, quartz powder and very fine quartz particles. Above 800 degrees Celsius, the reaction between the free surfaces of quartz and lime begins. For simplicity, this reaction is considered as a dissolution reaction (ie dissolution of quartz in lime) which causes the formation of siliceous-lime glass. With increasing temperature and time, the percentage of silica in this glass increases. The mentioned glass can crystallize and produce cristobalite at a temperature of 1300 degrees Celsius.