Provided herein are methods comprising a) calcining limestone in a cement plant to form carbon dioxide and calcium compound selected from calcium oxide, calcium hydroxide, or combination thereof; b) treating the calcium compound with N-containing salt in water to produce an aqueous solution comprising calcium salt and N-containing salt; and c) contacting the aqueous solution with the carbon dioxide under one or more precipitation conditions to produce a precipitation material comprising calcium carbonate and a supernatant aqueous solution wherein the calcium carbonate comprises vaterite.

Systems and methods to effectively sort calcined lime (quicklime) particles to produce products with more consistent size and burn time characteristics after the quicklime particles have been created and without the use of specialized additives. Specifically, such systems and methods sort the quicklime particles below a selected size into a softer burned and harder burned fraction based on their size. The fractions are burned in the kiln together and as a singular product, but can be classified from each other after calcining.

Systems and methods to effectively sort calcined lime (quicklime) particles to produce products with more consistent size and burn time characteristics after the quicklime particles have been created and without the use of specialized additives. Specifically, such systems and methods sort the quicklime particles below a selected size into a softer burned and harder burned fraction based on their size. The fractions are burned in the kiln together and as a singular product, but can be classified from each other after calcining.

A process for producing a highly calcined and uniformly calcined product from a feedstock. The process comprising the steps of grinding the feedstock to powder, preheating the powder, and calcining the powder in a reactor plant that comprises a number of reactor segments in which a flash calciner is used in each progressive reactor segment to incrementally react the powder by raising the temperature in each segment. The last segment may be a high-temperature reactor that has a controlled residence time and temperature that may allow controlled finishing of the calcination process to achieve a desired degree of calcination and sintering of the product; and cooling of the product.

A process for producing a highly calcined and uniformly calcined product from a feedstock. The process comprising the steps of grinding the feedstock to powder, preheating the powder, and calcining the powder in a reactor plant that comprises a number of reactor segments in which a flash calciner is used in each progressive reactor segment to incrementally react the powder by raising the temperature in each segment. The last segment may be a high-temperature reactor that has a controlled residence time and temperature that may allow controlled finishing of the calcination process to achieve a desired degree of calcination and sintering of the product; and cooling of the product.

The present invention provides an apparatus and a method for producing cement through flue gas desulfurization, and specifically provides an apparatus and a method for simultaneously producing magnesium sulfate cement during a magnesium oxide based flue gas desulfurization process. The apparatus of the present invention includes a flue gas desulfurization equipment, a concentration equipment, a crystallization equipment, a centrifugation equipment, a drying equipment, a waste ash supplying equipment, a slag material supplying equipment, a mixing equipment, etc. By adopting the apparatus and method of the present invention, the problems in the present conventional cement production such as high energy cost, severe damage to the environment and so on can be solved, and the problems like high production cost of ordinary magnesium sulfate cement and high transportation cost of supplies thereby causing incapability in a large scale market spreading and application can also be solved.

An improved lime mud recycling system including a camera proximate the kiln outlet imaging the granular lime and providing outlet images of the granular lime exiting the kiln, a processor analyzing the outlet images of the granular lime and providing pebble size distributions for the granular lime exiting the kiln, as well as a controller communicating with the processor comparing the pebble size distribution of the granular lime exiting the kiln with predetermined prescribed operating parameters for pebble size distributions for the granular lime exiting the kiln and issuing (I) a notification and/or (II) a control signal prompting remedial action when the pebble size distributions for the granular lime exiting the kiln are outside of the predetermined prescribed operating parameters.

Systems and methods for impurity removal to limestone using modifications to the typical calcination process of turning calcium carbonate into calcium oxide. Specifically, substantially increasing the temperature to 1100 C. or higher and increasing soak time can result in reductions in certain undesirable impurities, particularly with regards to lead and lead compounds.

Systems and methods for impurity removal to limestone using modifications to the typical calcination process of turning calcium carbonate into calcium oxide. Specifically, substantially increasing the temperature to 1100 C. or higher and increasing soak time can result in reductions in certain undesirable impurities, particularly with regards to lead and lead compounds.

Method and installation for calcining cement raw meal in a calciner whereby fuel and a calciner oxidant having an oxygen content of at least 30% vol are introduced into the calciner so as to generate either an oxidant-lean zone or a fuel-lean zone in the calciner located between the lowermost fuel inlet level and the lowermost oxidant inlet level of the calciner, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or within the oxidant-lean, respectively the fuel-lean zone.