Mineralogical, chemical, and geological aspects of four types of clay deposits in Las Aguilas Formation northwest of Barker in Buenos Aires Province, Argentina, indicate that these products of lateritic alteration of Precambrian granite are predominantly kaolinitic with minor amounts of halloysite, illite, and chlorite. Minor amounts of quartz, feldspars, and ferric oxides are also present. Of the four types, one is suitable for high quality refractories, another can be used for wall tiles and china, and a third, the most abundant, can be used for red ceramics; the fourth has no special use. The abundance of the clays is calculated to exceed eleven million metric tons.

Three clay materials (codded MY3, KG and KK) from western Cameroon were selected and investigated for the production of refractory bricks. Samples MY3 and KG are kaolinite-rich materials, having clay mineral contents of 88% and 72%, respectively, whereas KK is a sand-rich material with a total clay content of 44%. Chamottes were prepared using each clay, and the ground chamottes were later used in the refractory formulation, with each raw clay used as a binding phase. After firing, the X-ray diffraction analyses of all of the refractory bricks indicated the same mineral assemblage made of quartz, cristobalite and mullite. The cristobalite is due to high-temperature conversion of quartz, whereas the mullite is due to clay mineral conversion. The evaluation of the linear shrinkage, physical properties (including bulk density and open porosity) and mechanical testing through refractoriness under load and compressive strength indicates that all of these clays could be used as raw materials for standard clay refractory materials. These results stand as a proof for the potential for these locally available materials to be used as raw materials for refractories that could be locally produced to reduce the cost of access to refractory raw materials faced by industries located in Cameroon.

Refractory castables containing alumina-magnesia/self-forming spinel(MgAl2O4) are used in impact pads of steel ladles in steelmakingprocesses. In order to understand the wear mechanisms of refractory materials, severalrecipes were tested from a corrosion, slag resistance and thermal shock point of view. Theresults show that the corrosion is extremely limited at the slag/refractory interface forall cases. Nevertheless, for higher cement alumina content castables, the formation ofcracks is observed in refractory castables into which slag can penetrate. The slag reactswith the alumina to form a new phase such as hibonite (CA6) and calcium dialuminate (CA2).The volumetric change of these reactions involving CA2 and CA6 lead to the apparition ofmacro-cracks. Thus, the penetration of slag and steel are increased, causing hotmechanical properties to degrade. For lower cement alumina castables, the formation ofmicro-cracks is avoided by controlling volume expansion. Thus, the slag deposit reactswith alumina grains and the matrix at the slag/refractory interface to produce amonomineral layer of hibonite. In this way, the monomineral layer acts as a barrier andlimits the penetration of slag and steel into the refractory lining. Thus, to increase thelifetime of refractory castables containing alumina-magnesia/self-forming spinel, it isadvised to control volume expansion in order to avoid the formation of cracks and limitthe penetration of secondary metallurgy steel ladle slag.