Use of industrial waste clays for the manufacture of a supplementary cementitious material (scm) and method for its manufacture

A method for producing a supplementary cementitious material (SCM) from calcined industrial waste clays comprising:

• a) homogenizing and crushing industrial waste clays, wherein said industrial waste clays comprise a raw kaolinite content greater than 25%, an aluminum content (Al2O3) greater than 17% and a ferric oxide content (Fe2O3) of less than 15%;
• b) drying the homogenized and crushed industrial waste clays to reduce moisture content;
• c) calcining the dried industrial waste clays at a temperature between 600° C.-1000° C.;
• and
• d) cooling the calcined industrial waste clays at a temperature up to 120° C., to obtain an 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.