The present invention pertains to a process for producing captured carbon dioxide. Calcium carbonate may be reacted with sulfur dioxide to produce calcium sulfite and gaseous carbon dioxide. Calcium sulfite may be thermally decomposed to produce gaseous sulfur dioxide. The processes may be used in conjunction with combusting various fuels such as a carbonaceous fuel, or a sulfurous fuel, or a nitrogenous fuel, or a hydrogen fuel, or a combination thereof.

The present invention provides a method and system for manufacturing cement wherein ground particles of cement and calcium sulfate are subjected to infrared sensors, laser sensors, or both, so that emanated, irradiated, transmitted, and/or absorbed energy having wavelengths principally within the range of 700 nanometers to 1 millimeter can be monitored and compared to stored data previously obtained from ground cement and sulfate particles and preferably correlated with stored strength, calorimetric, or other data values, such that adjustments can be made to the mill processing conditions, such as the form or amounts of calcium sulfate (e.g., gypsum, plaster, anhydride), or cement additive levels. The strength and other properties of cement can be thus adjusted, and its quality can be more uniform.

A cement manufacturing plant can include at least one emission abatement mechanism. In some embodiments, the emission abatement mechanism can utilize a plurality of pulsed gases passed through a reactor to treat a solid particulate material passed through the reactor. The pulsed reactant gas can be pulsed through the reactor so that the pulsed gas passes from a middle portion of the reactor to a first end of the reactor at which the solid particulates can be fed into the reactor. In some embodiments, the reactant gas can be output from the first end to a down corner or other reactant gas conduit for transport to a treatment device.

A system for reducing NOx emission levels during the manufacture of cement clinker having a calciner unit with the following features: an upper portion; a lower portion; a NOx reduction zone in the lower portion; a tertiary air inlet in the upper portion for introducing tertiary air into the upper portion; a main calciner meal inlet located above the NOx reduction zone for introducing a main calciner meal portion into the upper portion; a first cooling calciner meal inlet located in the NOx reduction zone for introducing a first cooling calciner meal portion into a periphery of the NOx reduction zone; and a fuel inlet located in or below the NOx reduction zone for introducing fuel into the reduction zone.

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods make use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

In a method for reducing the NOx emissions of a rotary kiln of a clinker production plant, fuel supplied through a burner of the rotary kiln is burned along with primary air fed through the burner, wherein the primary air has a lower oxygen content and the primary air has an oxygen content reduced relative to that of the ambient air and a temperature increased relative to that of the ambient air, and the primary air is obtained by mixing ambient air with exhaust gas from the rotary kiln or from a heat exchanger connected to the rotary kiln and used for preheating raw meal. The primary air is further obtained by mixing with hot air, in particular waste air from a clinker cooler.

The present invention pertains to a process for producing captured carbon dioxide. Calcium carbonate may be reacted with sulfur dioxide to produce calcium sulfite and gaseous carbon dioxide. Calcium sulfite may be thermally decomposed to produce gaseous sulfur dioxide. The processes may be used in conjunction with combusting various fuels such as a carbonaceous fuel, or a sulfurous fuel, or a nitrogenous fuel, or a hydrogen fuel, or a combination thereof.

The present invention pertains to processes of, for example, preparing zinc oxide and other substances. In one embodiment an exemplary process pertains to reacting ammonium chloride with zinc oxide to form a zinc chloride, gaseous ammonia, and gaseous water vapor. The zinc chloride may be reacted with sulfuric acid to form a zinc sulfate and hydrochloric acid. The zinc sulfate may be decomposed to produce zinc oxide among other substances.

The present disclosure relates to a visible light-catalyzed translucent concrete, and a preparation method and use thereof. The preparation method includes: extracting an iron oxide from a copper slag, mixing the iron oxide with TiO.sub.2 to obtain a photocatalyst, and then mixing the photocatalyst with an additive to obtain a photocatalytic slurry; preparing a concrete slurry using the copper slag after iron extraction as an aggregate; and pouring the photocatalytic slurry, the concrete slurry, and the photocatalytic slurry in sequence into a mold pre-laid with an optical fiber, to obtain the visible light-catalyzed translucent concrete. In the visible light-catalyzed translucent concrete, iron in the copper slag is used as a part of raw materials of the photocatalyst, and the copper slag after iron extraction is used as an aggregate to replace natural sand and gravel. This solves environmental pollutions caused by the copper slag and realizes resource utilization.

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, SiO.sub.2, Al.sub.2O.sub.3, and Fe.sub.2O.sub.3; and, optionally, SO.sub.3, to form a raw meal comprising CaO, SiO.sub.2, Al.sub.2O.sub.3, and Fe.sub.2O.sub.3; and, optionally, SO.sub.3, wherein the molar ratios among the aforementioned oxides is given by Formula I: (CaO).sub.1(SiO.sub.2).sub.a(Al.sub.2O.sub.3).sub.b(Fe.sub.2O.sub.3).sub.c(SO.sub.3).sub.d, wherein: a is comprised from 0.05 to 1, b is comprised from 0.01 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).