Development of Alumina-Modified Tsaragi Aluminosilicate Clay for High-Performance Furnace Lining Applications

Introduction:
The development of locally sourced refractory materials is essential for reducing dependence on imported raw materials and supporting sustainable industrial growth. This study investigates the refractory properties of Tsaragi Aluminosilicate clay (ASC) obtained from Edu Local Government Area, Kwara State, Nigeria, and evaluates the influence of alumina addition on its suitability for refractory brick production and furnace lining applications. Despite its abundance, Tsaragi clay remains relatively underexplored for high-temperature engineering applications.

Methods:
Tsaragi ASC was blended with alumina at compositions ranging from 20 to 40 wt.% and processed into refractory brick specimens. The physical and mechanical properties of the developed refractories were evaluated through measurements of bulk density, apparent porosity, permeability, linear shrinkage, cold crushing strength, and thermal shock resistance. The effect of increasing alumina content on the performance characteristics of the refractory composites was systematically analyzed.

Results:
The results revealed that increasing alumina content improved the refractory characteristics of the clay. Linear shrinkage decreased from 2.30% to 2.00%, while apparent porosity decreased from 18.54% to 13.26%, indicating enhanced densification and dimensional stability. Permeability also decreased with increasing alumina addition. Thermal shock resistance improved from 26 to 33 cycles at 30 wt.% alumina, demonstrating enhanced resistance to repeated heating and cooling. Cold crushing strength increased from 18,500 kN/m² to a maximum of 20,300 kN/m² at 30 wt.% alumina before declining at higher alumina contents. Bulk density decreased slightly from 1.81 to 1.70 g/cm³ across the investigated compositions.

Conclusion:
Alumina addition significantly improves the refractory performance of Tsaragi ASC. An alumina content of approximately 30 wt.% produced the optimum balance of mechanical strength, thermal shock resistance, and dimensional stability. The findings demonstrate the potential of alumina-modified Tsaragi clay as a viable indigenous refractory material for high-temperature industrial applications.