Introduction to properties of co sintered magnesia chrome bricks

3) Re bonded magnesia chrome brick

The rebonded magnesia chrome brick is a refractory product made of high temperature sintered magnesia chrome or fused magnesia chrome raw materials by re sintering at above 1750 ℃; The re bonded magnesia chrome brick has uniform spinel phase distribution and good direct bonding between grains. The re bonded magnesia chrome brick has better corrosion resistance and erosion resistance than ordinary silicate bonded magnesia chrome brick and direct bonded magnesia chrome brick.

(4) Semi re bonded magnesia chrome brick

Semi rebonded magnesia chrome brick is a transitional product between rebonded bricks and direct bonding bricks, where a part of directly bonded magnesia chrome brick raw materials are used to replace the pre synthetic raw materials in the rebonded bricks. Due to the use of high-grade magnesia sand and other non pre synthetic raw materials, it has better thermal shock resistance than the rebonded magnesia chrome bricks.

(5) Co sintered magnesia chrome brick

Co fired magnesia chrome bricks, also known as full synthetic magnesia chrome bricks, are made of high-quality sintered magnesia chrome sand with high pressure ball press or ultra-high temperature. All of them are used as raw materials for making bricks and are fired at high temperatures. They have good corrosion resistance and high temperature volume stability.

(6) Cast magnesia chrome brick

The fused cast magnesia chrome brick is a refractory specially designed for copper smelting industry. The production adopts the fused casting principle, that is, after the raw materials and additives are pretreated by mixing, crushing, pressing and other methods, the materials are melted into liquid in an electric furnace, the rough billets are cast in a grinding tool, and finally the rough billets are processed by cutting and other methods to melt the fused cast magnesia chrome bricks.

Fused cast magnesia chrome brick has unique advantages in slag penetration resistance, but it is difficult to produce and expensive. Besides, it can be regarded as a rigid body after overall molding, with fewer pores and microcracks for cushioning, and poor thermal shock resistance.

Since the 1950s, silicate bonded magnesia chrome bricks have been used in the copper smelting industry. With the development of copper smelting technology, silicate bonded magnesia chrome bricks have faded out of the sight of copper smelting, but they are still used in some converters, mainly for upper furnaces, flue openings and other locations.

At present, the process of directly bonding magnesia chrome bricks, directly bonding magnesia chrome bricks to build the furnace body, and electric melting combined with magnesia chrome bricks to build the converter lining at the tuyere, furnace mouth and other locations has been widely used in the converter.

Taking the lining construction of a 150t copper converter in a factory in Inner Mongolia as an example, the ordinary silicate bonded magnesia chrome bricks are used to build the cylinder and end wall lining, and the direct bonded magnesia chrome bricks with high chromium content are used to build at the positions such as the slag line of the tuyere where the erosion is serious, which has achieved good results.

A copper plant in Yunnan has also achieved good results by using improved electric melting combined with magnesia chrome bricks to build the tuyere, extending the furnace life and reducing the period of minor repair.

Generally speaking, ordinary magnesia chrome bricks are mostly used to build furnace lining in China, and direct bonding bricks or electric melting and then combining magnesia chrome bricks to build tuyere, slag line, furnace mouth and other positions are the general methods for laying copper converter furnace lining.