International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The development refers to an innovative technology and technological scheme of a workshop for the production of beehives made of amorphous quartz ceramics. The conditions for obtaining stable suspensions from quartz glass are emphasized and investigated. The time for the treatment of the glass in the grinding device, the amount of water, the influence of the modifiers in stabilizing the suspension by adjusting the pH level, as well as the most suitable sedimentary composition of the glass particles are established. The factors determining the speed and degree of sintering of the ceramics are investigated and established. They include the density of the raw products, the dispersion of the quartz glass particles and its purity, as well as the environment in the furnace and the sintering mode.

The results of the plastic forming of ceramic pavers with a large volume and size are observed to produce better compaction of the raw material. The used ceramic mixture is based on a sedimentary rock with relatively high moisture content and firing shrinkage which gives the common yellow colour after a high-temperature liquid phase synthesis. The results of one-fold pressing revealed the occurrence of deformation processes in the drying stage and during the temperature regime. As a consequence, the pressing pressure should be increased and the residual water amount needs to be reduced to an optimal content.

The phase and petrographic analysis of a part of previously prepared test samples of coloured petrographic materials coloured with different contents of CuO, SnO2, CoO, Cr2O3 were studied. The raw materials are based on metamorphic rocks – dolomite marbles from the village of Ustrem and the village of Mramor, processed by melting at 1450°C, so that after crystallization, petrographic phases are obtained, which are confirmed by X-ray phase and petrographic analysis. The main characteristics of the colouring aggregates and their effect on the mineral composition and crystal structure are described.

The research is related to the creation of new compounding formulations for the production of “yellow” paving stones. This was necessary due to denied access to a potential source of suitable raw material from the deposit near the village of Svetlen, Popovo municipality. Marlstone raw material from this deposit has the necessary qualities for such production, as a result of which, after hightemperature liquid-phase synthesis, new petrurgic phases with high physicochemical and mechanical properties can be formed. The new compounding formulation of the molding mass was developed on the basis of marlstone sedimentary rock from the Alexandra deposit, located near the village of Lovets, Targovishte district. The use of this compounding formulation makes it possible to obtain appropriate physicochemical and mechanical properties and a yellow coloring equivalent to that of the reference samples.