Study On Calcined Carbonaceous Shale As Active Blending Material

Carbonaceous shale is one kind of clay rock symbiotic with coal seam,composition is more complex, which contains a large number of dispersed carbonizedorganic matter, widely distributed in western region of China. Carbonaceous shale hasnot been effective resource utilization, abandoned carbonaceous shale not only takes upa lot of land but also easy to cause environmental pollution. For carbonaceous shale andclay mineral characteristics of burnt clay with activity, this paper proposes the idea ofcalcined carbonaceous shale, which was used for activity blending material.Firstly, X-ray diffraction analysis (XRD), X-ray fluorescence spectroscopy (XRF),TGA-DTA (TG-DTA) combined with high-temperature furnace calcination were usedto study the high-temperature decomposition process of carbonaceous shale and theactivity generated area, to determine the optimum calcining system of carbonaceousshale. Research of calcined carbonaceous shale under different calcination system usedas reactive blending materials, influence on cement, mortar. Meanwhile, Electrolyticmanganese residue(EMR) was combined with carbonaceous shale for calcination, usingsulfate of EMR to stimulate activity of calcined carbonaceous shale, as well as thepresence of limestone under the conditions, can generate favorable development on thestrength properties of quasi-sulphoaluminate cementitious materials to do the research.Results showed that: carbonaceous shale main minerals are quartz, illite, chlorite,anorthite, the main chemical ingredient is SiO2and Al2O3, etc.; Carbonaceous shale bycalcining dehydration and decomposition temperature range is400~800℃, chloritebasically been completely decomposed at600℃, the decomposition temperature of illiteis wider, until there is a small presence of900℃, there is no new diffraction peaks wereobserved after decomposition of chlorite and illite, indicating that chlorite and illitetransformed into amorphous SiO2and Al2O3, which is then calcined carbonaceous shalehas been the source of activity.The best calcination system of carbonaceous shale is that heating rate controlled at10℃/min, carbonaceous shale calcined at800℃, holding0.5hours with high activity,the activity can reach84%, to meet the national standard requirements for pozzolanicactivity of activity blending material. Too high or too low calcination temperature isdetrimental to the development of the activity, the longer the holding time, the lower theactivity. Calcined carbonaceous shale as cement admixture, the calcined carbonaceous shalehas great influence on cement setting time, with good retarding effect, Content greaterthe retarding effect is more obvious. The dosage of calcined carbonaceous shale is10%~40%, the best effect is10%, with the increase of dosage, the decrease of strengthof cement; Comprehensive carbonaceous shale resource utilization and maximize itsimpact on the performance of cement to the best content of30%,28d strength can bereached to51.83Mpa, is a kind of good admixture.Calcined carbonaceous shale as admixture, the dosage is10%~30%, the addition ofcalcined carbonaceous shale to mortar working performance is well. Water curing isbetter than standard curing for the favorable development of volcanic activity；In thestudy of different calcined carbonaceous shale dosage on the performance of mortar,30%at best. Research results showed that the different ratio of modified carbonaceousshale has different activity. Under the same calcination temperature, the modificationeffect G1is better, the activity of modified carbonaceous shale as the carbonaceousshale content ratio decreases and lower, indicating that the activity of the modifiedcarbonaceous shale mainly by calcined carbonaceous shale provided; while the sameratio,800℃calcined is best. Calcined at800℃G1was the best modification effect,the activity can reach87%, to meet the national standards for active pozzolanic activityblending material requirements.