Njerwa zapamwamba za alumina

A. High alumina brick application

Mainly used for lining of blast furnaces, hot blast furnaces, electric furnace tops, blast furnaces, reverberatory furnaces, and rotary kilns. In addition, njerwa zapamwamba za aluminas are also widely used as open hearth regenerative checker bricks, plugs for pouring systems, nozzle bricks, etc. However, the price of high alumina bricks is higher than that of clay bricks, so it is not necessary to use high alumina bricks where clay bricks can meet the requirements. To

B. Performance of high alumina bricks:

(1) Refractoriness

Kukonzanso kwa njerwa zapamwamba za alumina ndikokwera kwambiri kuposa njerwa zadothi komanso njerwa za silika, mpaka 1750 ~ 1790 ℃, zomwe ndi zida zapamwamba zopangira. Refractoriness imakhudzidwa makamaka ndi zomwe zili, mtundu ndi kuchuluka kwa Al2O3, ndipo kukonzanso kumawonjezeka chifukwa cha zomwe Al2O3 ikuwonjezeka.

(2) Load softening temperature:

Chifukwa njerwa zapamwamba za alumina zimakhala ndi Al2O3 yokwanira, zosowa zochepa, komanso matalasi ocheperako, kutentha komwe kumachepetsa kutentha kumakhala kwakukulu kuposa njerwa zadongo. Komabe, chifukwa makhiristo a mullite samapanga maukonde, kutentha kochepetsa kutentha sikukhala kofanana ndi njerwa za silika.

(3) Thermal conductivity:

Njerwa zapamwamba za alumina zimakhala ndi matenthedwe abwino kuposa njerwa zadongo. Chifukwa chake ndikuti pali magalasi ochepa omwe amakhala ndi matenthedwe otsika kwambiri pazinthu zamagetsi apamwamba, pomwe kuchuluka kwa mullite ndi corundum makhiristo okhala ndi matenthedwe otenthedwa bwino kumachulukirachulukira, komwe kumathandizira kutentha kwa mankhwala.

(4) Thermal shock resistance:

Kutentha kwamphamvu kwa njerwa zapamwamba za alumina kuli pakati pazinthu zadongo ndi zinthu za siliceous. Kutentha kwamadzi kozizira pa 850 ° C ndi 3 kapena 5 kokha. Izi zili choncho makamaka chifukwa chakuti corundum imakhala yotentha kwambiri kuposa mullite popanda kusintha kwa kristalo. Pakadali pano, ndizotheka kukonza tinthu tating’onoting’ono ta mankhwala, kuchepetsa zomwe zili ndi ufa wosalala, ndikuwonjezera kukula kwakukulu ndi tinthu tating’onoting’ono ta clinker kuti tithandizire kukana kwamphamvu kwa malonda.

(5) Slag resistance:

Njerwa zapamwamba za alumina zili ndi Al2O3 yambiri, yomwe ili pafupi ndi zida zotsalira, ndipo imatha kukana kukokoloka kwa slag acidic ndi slagine slag. Chifukwa cha kuphatikizidwa kwa SiO2, kuthekera kokana slag yamchere ndikofooka kuposa slag acidic. Kuphatikiza apo, kukana kwa slag kwa njerwa zapamwamba za alumina kumakhudzanso kukhazikika kwa malonda mu slag. Nthawi zambiri, pambuyo poumba kuthamanga kwambiri ndikuwombera kotentha kwambiri, zopangidwa ndi porosity zochepa zimakhala ndi kukana kwakukulu kwa slag.

The parameter index of high alumina bricks varies widely, and its physical properties should be determined according to the grade of the product and the place of use when it is used. At present, the general high alumina brick standard GB2988-88 is generally adopted. If you need to use super high alumina bricks, please refer to GB/T 2988-2012 standard physical and chemical indicators. The index of high alumina brick is the basic performance requirement. According to the conditions of use, creep resistance and thermal shock resistance should also be considered. The chemical resistance directly depends on the A12O3 content and porosity.

(6) Physical and chemical indicators: