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High alumina bricks, clay brick molding brick often encountered problems

In the high alumina brick, clay brick molding process of forming the internal structure of the brick, the most commonly encountered problems are:
(1) green body fracturing (or called cracking), which is formed during the pressurization process perpendicular to the pressure direction of the layered cracks. In addition to the reasons for this phenomenon caused by the mold, mainly due to the blank in the air is not discharged due. When the billet moisture is especially prone to such dehiscence; In addition, excessive powder, binder is too small, and the pressure is too high and other unreasonable process parameters are also factors that cause dehiscence.
(2) uneven green body density. The reason is due to the billet pressure, the particles and particles between the particles and the mold wall there is friction between the impede the pressure evenly transmitted to the blank body parts of the uneven pressure, resulting in each part of the dense Degree is different. In addition, the billet filling height and the ratio between the size of the size of the pressure is also an important factor in uneven density. The larger the ratio between the filling height and the area under pressure, the more uneven the pressure transmission. In the direction of pressure, the pressure decreases from the pressing surface along the height of the green body, and the density distribution of the green body correspondingly increases from compact Loose; if double-sided pressure, the density of the body was dense between the two ends and the middle sparse. Therefore, to reduce the density difference between forming the body, you need to pay attention to mold design and molding pressure way.
Molten brick first dried in a drying room at 50 ~ 60 ℃ to a residual moisture of not more than 2.5%, before being transported to the firing section kiln firing. The firing of refractory brick products is carried out in a down-furnace or tunnel kiln. Kiln method using paperback, special products and large, special-shaped refractory bricks, you need to use specially designed tool bricks. See the burning system of thin-walled products firing system. Burn finished, with the kiln cooling. In order to speed up the turnover of the kiln, the first kiln door can be opened after the flameout, the second kiln door opened after 8h, and the third kiln door opened after 8h. 72h after the flame can be cooled to the kiln blast. Of course, this cooling system with the size of the kiln and make the appropriate changes.
Out of the kiln after the product should be quality inspection and final shape and size of the cold. In particular, like the assembled corundum on behalf of the platinum crucible bricks, the need to assemble close-fitting, therefore, the dimensional tolerances, flatness, surface roughness, and so have high requirements, must be accurately processed in accordance with the drawings.
Fully meet the quality requirements of the product, and ultimately as a finished product storage.
High alumina brick, clay brick products specifications and shape there are many. Such as the standard brick, bricks, straight brick, ax brick, knife blade, banana brick, arch foot brick, vaulted brick, brick burner, and various types of bricks. Divided by chemical composition of high alumina brick, clay brick, pure corundum brick, corundum brick containing titanium, chromium-containing corundum brick, containing mullite corundum brick, carbon-containing corundum brick, the corresponding quality indicators are also some differences.