The Research On Durability Of Petroleum Coke Desulfuration Residues Aerated Concrete

Petroleum coke desulfuration residues are industrial wastes which are made fromhigh sulfur petroleum coke with circulating fluidized bed combustion technology,containing mainly CaO and CaSO₄Ⅱ.The aerated concrete with petroleum cokedesulfuration residues instead of some lime and gesso is called petroleum cokedesulfuration residues aerated concrete. It may increase the content of CaSO₄Ⅱinaerated concrete and influence the durability of the aerated concrete such as poorstability for dehydrate gypsum making the volume expansion, that petroleum cokedesulfuration residues displace some lime and gesso. Aiming at this issue, the papersystematically studied on the petroleum coke desulfuration residues aerated concreteproducts which had the different substitution rate, and found out the optimalreplacement ratio of petroleum coke desulfuration residues, and proved that CaSO₄Ⅱwas stable in the aerated concrete. In addition, it established the foundation forpetroleum coke desulfuration residues applied in the aerated concrete.The subject is based on the program of the research of the application of milledhigh-sulfur petroleum coke desulfuration residues. It mainly includes:1) Preparingcalcareous materials used in aerated concrete called composite lime with desulfurationpetroleum coke residues and lime slag mixed and grinded by1:2.2) Based on theactual mix proportion in an aerated concrete plant （factory mix ratio for short）,preparing aerated concrete with composite lime instead of all of the lime and gypsumin the factory mix ratio respectively according to the lime dosage of95%,100%,105%,110%and120%.3) Researching on the change rule of the physical andmechanical properties of aerated concrete along with the increase of lime replacementratio.4) Studying on the change rule of aerated concrete products of differentreplacement ratio under different condition （natural state, standard curing, long-termfull water）.5) Researching on the durability of aerated concrete products of differentreplacement rate, including the long-term water resistance, dry shrinkage, frostresistance and stability of carbide.6) Taking the aerated concrete products under different condition （natural state, standard curing, long-term full water）, analyzing thechange rule and stability of anhydrite in aerated concrete by micro analysis （XRF andXRD）.The results are as follows:1) with the improvement of composite limereplacement ratio, compressive strength of aerated concrete firstly increases and thentends to be stable. When replace rate is110%, specific strength is the largest, that isthe performance is optimal.2) The aerated concrete block under the natural state, hasbetter strength than that in the factory. Compared with the factory and naturalconditions, standard curing is more conducive to improving the strength of theproducts; the strength of aerated concrete products under the condition of long-termfull water reduces and decreases deeply with the increment of replacement ratio.3)The softening coefficient of aerated concrete increases with the increment ofreplacement ratio and ranges between0.68and0.79. Drying shrinkage test shows that,with the improvement of replacement ratio, the largest dry shrinkage value decreases;when the replacement ratio is110%, the frost resistance of products is best. When infactories or replacement ratio is95%or100%, the frost resistance of the productscan’t meet the requirements. After complete carbide, the strength of the block greatlyreduces, and carbonation coefficient tends to improve with the increase ofreplacement ratio and ranges between0.65and0.83.4) No matter the aeratedconcrete is in natural state, standard curing or under the condition of long-term fullwater, the diffraction peak of CaSO₄2H₂O are not found clearly in XRD spectrum,which proves that the anhydrite in aerated concrete is stable.5) The test results showthat when the composite lime replacement ratio is110%, any performance of productsis best and meets the standard requirements.