Uses of industrial waste clays for the manufacture of a supplementary cementitious material (SCM), wherein the industrial waste clays are kaolinitic clays selected from reject tails, cyclone tails, overburden/interburden from a refractory, ceramic, paper, oil or kaolin industries are described herein. A supplementary cementitious material (SCM) derived from calcined industrial waste clays wherein the obtained SCM maintain the same performance in comparison with other materials traditionally used and a method for manufacturing said SCM.

A pore-forming microsphere homogenizing device and method include steps of: firstly homogenizing the pore-forming microspheres made of the cow dung into the clay paste; secondly homogenizing the materials by using the kneading gear and the ejection cylinder rotating in opposite directions for kneading the clay paste while ejecting the pore-forming microspheres; and thirdly homogenizing the materials by using the telescopic kneading part and the ejection cylinder together for further kneading the clay paste while ejecting the pore-forming microspheres. With the foregoing processes, uniform and complete closed pores are uniformly distributed in the clay bricks, so that the strength of the clay bricks remains unchanged while clay usage is reduced.

A pore-forming microsphere homogenizing device and method include steps of: firstly homogenizing the pore-forming microspheres made of the cow dung into the clay paste; secondly homogenizing the materials by using the kneading gear and the ejection cylinder rotating in opposite directions for kneading the clay paste while ejecting the pore-forming microspheres; and thirdly homogenizing the materials by using the telescopic kneading part and the ejection cylinder together for further kneading the clay paste while ejecting the pore-forming microspheres. With the foregoing processes, uniform and complete closed pores are uniformly distributed in the clay bricks, so that the strength of the clay bricks remains unchanged while clay usage is reduced.