How to improve the thermal shock resistance of high alumina bricks?

How to improve the thermal shock resistance of high alumina bricks?

Using grade 1 bauxite clinker and fused white corundum powder as raw materials, adding an appropriate amount of expansion agent, forming and heat treatment at 800 ℃, high-alumina bricks with good thermal shock stability can be obtained

Using grade 1 bauxite clinker and fused white corundum powder as raw materials, adding an appropriate amount of expansion agent, molding and heat treatment at 800 ℃, high-alumina bricks with good thermal shock stability can be obtained. in

The chemical composition of grade 1 bauxite clinker is (%): Al2O3: 83.50, SiO2: 9.39, Fe2O3: 1.29, K2O+Na2O: 0.86

The Al2O3 content of fused white corundum powder is 95.36%

Clay particle ratio: 15~35% of first-grade soil clinker <5mm, 20~40% of first-grade clinker fine powder <0.088mm, 5~10% of fused white corundum powder, andalusite and

Sillimanite compound expansion agent 6~15%, chemical binder 6~10%.

Mixing is carried out in a mixing machine. First add 50% chemical binder to the coarse particles, after mixing for 3~5min, then add the fine powder, compound expansion agent and the rest of the chemical binder

The particle size composition of the mud is as follows: 5~3mm: 18.4%, 3~1mm: 26.7%, 1~0.5mm: 3.5%, 0.5~0.1mm: 8.2%, <0.1mm: 43.2%,

The moisture content is 3%, and the material is trapped for more than 2h. The bricks are formed on a 300t friction brick press, and the bulk density is greater than 2.85g/cm3. After the bricks are dried at 160 ℃, they are heated at 800 ℃ in the pouring flame density.

Heat treatment for 4 h. The physical and chemical indicators of this brick are as follows: Al2O3: 70.01%, SiO2: 13.71%, apparent porosity 20.4%, compressive strength at room temperature 57.4MPa, load

The melting temperature is 1530 ℃; 1500 ℃, 2h reburning line change rate +3.7%. Thermal shock stability (1100℃, water cooling) is more than 10 times. This kind of brick is used for 5t electric furnace roof, no falling or chipping phenomenon

There are also units that have patented inventions for a kind of high-abrasion-resistant and thermal-shock-resistant high alumina bricks used in different dense furnaces, which include the following components by weight:

3~5m super bauxite aggregate 5~-15 parts; 1~3mm super bauxite aggregate 30~40 parts 0~1mm super bauxite aggregate 10~20 parts super ground fine powder (220 mesh)

20~30 parts zirconium carbide fine powder (320 mesh) 5~7 parts; Suzhou No. 2 mud 1~3 parts; chromium carbide fine powder (320 mesh) 2 parts; composite binder 8~10 parts; water 4-6 parts .

The high alumina bricks produced by the above formula ratio can effectively improve the thermal shock resistance.