Process for producing a cement clinker at low temperature

(22) 07.06.2017

(43) 09.05.2019

(57) The invention provides a process for producing a cement clinker comprising: (i) mixing one or more starting materials providing each at least one or more of CaO, SiO₂, AI₂O₃, and Fe₂O₃; and, optionally, SO₃, to form a raw meal comprising CaO, SiO₂, Al₂O₃, and Fe₂O₃; and, optionally, SO₃, wherein the molar ratios among the aforementioned oxides is given by Formula I: S(CaO),(SiO₂),(Al₂O₃), (Fe₂O₃),(SO₃), wherein: „a“ is comprised from 0.05 to 1, „b“ is comprised from 0.1 to 0.6, „c“ is comprised from 0.001 to 0.25, and „d“ is comprised from 0 to 0.3 and wherein at least 35 % (p/p) of the starting materials of the raw meal have a critical microwaves absorbance temperature (Tc) comprised from 15 to 650° C. and a critical microwaves absorbance time (tc) comprised from 1 min to 1 h; (ii) heating the raw meal by irradiating with microwaves during 15 min to 3 h to reach a sintering temperature comprised from 300 to 950° C.; (iii) maintaining the microwave sintering temperature of step (ii) during 1 min to 3 h by further irradiating with microwaves; and (iv) cooling the clinker obtained in step (iii).

(71) Fundacion Tecnalia Research & Innovation, Derio (ES)