The Research On The Composition And Alkali Resistance Of Chrome Free Refractory For Alkali Recovery Furnace

Magnesia chromite refractory is the traditional refractory material for lining ofalkali recovery furnace, but when it is manufactured and used, hexavalent chromecompounds will give rise to detrimental effect on environment and human’s health.With the gradaual awakening of the people’s consciousness about environmentprotection, to prepare one kind of bricks for alkali recovery furnace which areenvironmental, high quality and long life is urgent affair. In this article, the alkaliresistance of white corundum, tabular corundum, andalusite, CaAl4O7/MgAl2O4(CA2/MA), alumina-rich MgAl2O4spinel AR90and AR78were fist studied. Theresults show that alkali reacts with AR90, AR78, CA2/MA respectively, causing smallvolume expansion, which generate a small amount of low density of compounds.However the reacts between tabular corundum, white corundum, andausite and alkalicause the larger volume expansion, which generate a large amount of low densitycompounds.Then, in order to research the influence of the addition of the types and quantityof powder on property of magnesia refractory, the powder of CA2/MA(65/35) andAR90replacing magnesia were added to magnesia refractory. The results show that,the physical properties of the samples which add the powder of CA2/MA are superiorto the samples which add the powder of AR90, the physical properties of the samplesare best when the adding of CA2/MA powder is20%and sintering temperature is1600℃. Due to the poor permeability resistance of magnesia material, the alkaliresistance testing find that alkali salt has more penetrative in the sample.In order to solve the problem of the poor permeability resistance of magnesia,magnesia was replaced of AR78and AR90. Using inorganic salt as binding agent,different sample preparations were used to research the property of MgO-MgAl2O4unburned refractory. The results show that with increasing the adding of spinel in samples, the volume expansion decreased, the bulk density first decreased and thenincreased, apparent porosity first increased and then decreased and the compressivestrength increased. When the proportion of added spinel is100%, the physicalproperties of sample is a little worse than chromite and the alkali resistance betweenspinel unburned refractory and chromite has little difference.Finally, adding spinel micropowder to spinel unburned refractory replacedequivalent spinel powder, for which researching the influence of adding spinelmicropowder on the property of spinel unburned refractory. The results show that withincreasing spinel micropowder added, the bulk density and the compressive strengthincreased, the volume expansion and apparent porosity decreased. The physicalproperty of AR90spinel can be comparable to chromite and the alkali resistanceproperty is superior to chromite.