WP3 – Synthesis of clinker products from CaO-poor industrial waste and marl clays
Start and end of the work package: from Month 07 to Month 27
The main work of the third stage will be related to the laboratory synthesis of clinker products, in which pyroxene and/or anorthite crystal phases are formed, combining CaO-poor industrial waste with marl clays.
Similar to the WP2 work, high-temperature microscopy and optical dilatometry tests will be carried out to determine the starting compositions, which can be characterized by an extended sintering interval and reduced sintering temperature. Particular attention will be paid to the interrelation between the processes of phase formation and sintering from the point of view of the position of the compositions in the crystallization fields of the separated crystalline phases.
One of the aims of these studies will be the synthesis of compositions with a good degree of sintering and increased crystallinity, which is a prerequisite for improved mechanical indicators. In similar ceramics obtained with traditional industrial clays [5] it was shown that phase formation also occurs during cooling and that this is associated with the formation of additional crystallization porosity. Therefore, it is planned to study the processes of crystallization during cooling and the related change of structure in these ceramics as well.
Then, as in WP2, research is planned with the selected compositions, which includes determination of optimal temperatures and times of heat treatment of each of them, DTA analyses, accurate determination of phase composition and structure of the samples with XRD and SEM-EDS analyses, determination of water absorption and total porosity.
Plasticity measurement studies are also planned. In this case, however, due to the use of the reduced amounts of marl clays in the batch compositions, calcination of part of the marls is not predicted. Instead, in some cases it is possible to apply preliminary heat treatment of the waste or its grinding to obtain different fractions. The change of initial porosity with forming pressure will also be investigated. It is important to compare firing shrinkage and the associated reduction in heat treatment time. Computed tomography will also examine the possible change in the structure of samples.
At the workshop organized under WP2, results obtained under RP3 will be also presented and discussed. The materials will be presented on the project site. As a result, articles will be prepared that will be directed to specialized international journals. These materials will be reported at international conferences.
The head of WP3 is Prof. Karamanov.