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Manufacturing procedure for zeolitized or geopolymerized material and produced material
P202330759
The invention relates to the procedure for manufacturing a new, more sustainable mineral material with, among other aspects, improved mechanical resistance, obtained after pre-firing macroscopic pieces of clay, with or without additives (for example, pore-forming residues), and subsequent alkaline hydrothermal treatment of these. This material is characterized by presenting significant contents of zeolite and/or geopolymeric gel, both developed during the hydrothermal treatment. The formation of these phases favors the closure of pores and, with it, the densification of the structure, the reduction of water absorption and a significant increase in mechanical resistance, compared to the starting ceramic material. Crystallized zeolites can, in turn, provide decontamination capacity. An also important advantage is that the pre-firing temperature can be much lower than those usually applied in the ceramic sector, resulting in significant energy savings, thereby reducing the economic and environmental cost of manufacturing. The proposed method and the developed material are potentially applicable in different sectors, such as construction, agriculture, geotechnics, civil and environmental engineering.
It starts from a pre-sintered piece, which can be prepared at relatively low temperatures (200-600ºC). An alkaline hydrothermal treatment is carried out on the piece to zeolitize it and harden it. This differs from the usual synthesis of zeolites with powdery precursors, which subsequently require sintering to form hardened pieces, which can generate loss of zeolite or low mechanical resistance if no prior pressing is applied. Apart from the functionality due to the presence of zeolites, there is a significant increase in the mechanical resistance of the pieces obtained by densification. This could be interesting, for example, in the ceramic sector to manufacture parts at lower temperatures and with mechanical resistance equal to or higher than usual. Highly zeolitized materials can be obtained with the desired shape by taking advantage of the plasticity of the raw material (clay), which can be extruded and molded according to needs, without the need for pressing or using molds. The products obtained could replace traditional ceramic construction materials, which would now be zeolitic, and could, for example, present decontaminating capacity.