Cement production

A method for manufacturing cement, comprising:

• (A) introducing, into a grinding mill, raw materials comprising clinker, a source of sulfate chosen from gypsum, plaster, calcium anhydrite, or a mixture thereof;
• grinding the raw materials, to produce a ground blend of particles comprising ground clinker and calcium sulfate;
• and separating the ground blend of particles within a classifier whereby a first portion of the particles or the finished cement is removed from the grinding mill and whereby a second portion of the particles is recirculated for further grinding in the grinding mill;
• (B) providing at least one infrared sensor system comprising a processor that is communicative with processor-accessible memory, the at least one infrared sensor system effective to detect at least one of emanation, reflectance, transmittance, or absorption of infrared energy in the range of 700-1400 nm by or through the ground blend of particles or finished cement provided in step (A), and generating output signals corresponding to the detected energy;
• (C) comparing, using the processor, the output signals generated in step (B) to data stored in the processor-accessible memory, the stored data comprising output signal values previously obtained from the at least one infrared sensor system measuring the emanation, reflectance, transmittance, or absorption of energy in the infrared spectrum of 700-1400 nm, the stored data being correlated with a physical or chemical property of the corresponding finished cement, hydrated cement, or cementitious product made with the cement;
• and
• (D) in response to the comparison in step (C), adjusting a grinding mill condition chosen from (i) adjusting amount and form of calcium sulfate introduced into the grinding mill in step (A);
• (ii) adjusting classifier settings thereby to change relative amounts of ground particles being removed from the grinding mill and being recirculated back into the grinding mill;
• (iii) adjusting amount, type, or both amount and type of cement additives introduced into the grinding mill;
• (iv) adjusting amount of water being introduced into the grinding mill;
• (v) adjusting amount of air provided by adjusting power or speed of a fan or blower connected to ventilate the mill;
• (vi) adjusting amount or type of supplemental cementitious material introduced into the grinding mill;
• or (vii) performing a combination of the foregoing adjustments of grinding mill conditions.