Impact of Chemical Composition of Fused cast AZS on Its Crystal Structure

The chemical composition of Fused cast AZS is one of the key factors that determines its crystal structure and physical and chemical properties. Effective control of its chemical composition is important to stabilize and improve the quality of fused cast AZS.

First select high pure raw materials, especially the main chemical composition such as Al2O3, SiO2, ZrO2 and Na2O. Reduce or avoid impurities such as Fe2O3, TiO2, CaO and MgO. With high pure raw materials, the crystal structure can be optimized and the physical and chemical properties can be improved.

Any change of chemical composition can change the crystal structure. If the content of SiO2 is too high, SiO2 can form mullite with Al2O3 in the alkali-free environment. The formation of mullite will reduce the glass phase and corundum in the crystal structure. As a result, the high performance mineral structure will be destroyed and become loose, and the baddeleyite and corundum will be bare and scattered.

ZrO2 has characteristics of high temperature resistance, high mechanical strength, good corrosion resistance to glass liquid and stable chemical property. The higher the content of ZrO2, the better its corrosion resistance. However, it has bad thermal chock resistance at 1000-1200?. If the content of ZrO2 is too high, the production of fused cast AZS can be difficult and the crystal structure become loose. The baddeleyite may drop into the glass liquid and cause pollution and glass defects such as stripes, stones and bubbles, which will not only influence the quality of glass but also damage the glass furnaces and reduce its service life.

The content of Na2O can affect the quality of fused cast AZS too. Na2O can constitute a structure for modifying the network of the matrix glass and exhibits an action to control the viscosity of the matrix glass and an action to inhibit the formation of mullite. If the content of Na2O is too low, the formation of mullite is accelerated and the fused cast AZS block is apt to crack. However, if it is too much, the superior non-exudation characteristic of matrix glass can not be obtained.

Impurities such as Fe2O3, TiO2, CaO, MgO, S and P should be avoided. They can affect the crystal structure and its physical and chemical properties and damage the glass furnace.