Alumina Hollow Ball Brick Making Process

[China Aluminum Network] Manufacturing Process First, alumina hollow spheres are prepared and alumina hollow bricks are made.

Step 1. Preparation of alumina hollow spheres Alumina hollow spheres were prepared using industrial alumina as a raw material, melted by eutectic melting and then blown. Electrofusion equipment is an electric arc furnace. The molten pool is made of graphite or other refractory materials, a flow opening is built on the edge, a nozzle for compressed air is installed on the outside of the flow opening, the nozzle is connected to the compressed air device by a pipeline, the furnace body can be tilted, and the electrode is a graphite product.

After the industrial alumina powder is added into the molten bath, it can be melted by electricity. When the temperature of the molten metal reaches or exceeds 2200°C, the molten metal is tumbling, that is, the furnace body is swayed to make the melt flow out; at the same time, the molten liquid is blown with compressed air. Due to the viscosity and surface tension of the melt, the melt forms a hollow sphere that envelops the air during the blowing and condensation process. After collection and screening, the pellets are stored separately according to different particles.

The proportion of alumina hollow spheres with different particle sizes varies with the pressure of the compressed air. The greater the pressure, the greater the number of small spheres.

The wall thickness of the hollow sphere varies with the particle size. When the particle size fluctuates in the range of 5 to 0.5 mm, the wall thickness correspondingly fluctuates in the range of 0.3 to 0.1 mm.

The larger the particle size of the hollow sphere, the smaller the natural bulk density; the smaller the particle size, the larger the natural bulk density. For example, when the particle size is 5.13 to 3.22mm, the natural bulk density is 470g/L; when the concentration is 3.22 to 2.0mm, 670g/L; when it is 2.0 to 1.0mm, it is 810g/L; 1.0 ~0.5mm, 915g/L.

Step 2 Manufacture of Alumina Hollow Sphere Bricks Alumina Hollow Sphere Bricks Alumina hollow spheres, sintered alumina fine powders and binders are compounded, formed, dried, and fired in certain proportions to obtain alumina hollow sphere bricks.

Alumina fine powder is produced by industrial alumina as a raw material and calcined after 1500°C, pickling, and drying.

The binder used for making bricks is usually an aqueous solution of aluminum sulfate or an aqueous solution of aluminum dihydrogen phosphate.

Alumina hollow spheres generally have a particle size of 5 to 0.5 mm, a rainfall of 65% to 70%, a fine alumina powder of 30% to 35%, and a binder dosage of 5%.

The above materials are mixed evenly and formed by vibration molding method. After the bricks are dried, they are fired at 1500-1800 DEG C to obtain fired bricks. The fired products can also be obtained without firing, or the linings can be directly constructed with amorphous materials.