A process for calcining a feed material can include passing a solid particulate material through a burner or adjacent a burner for being pass through a flame formed by the burner to facilitate calcination of the material. The material can be emitted from the flame of the burner within a calciner for passing through a body of the calciner to an outlet for further calcination of the material so the material has a pre-selected residence time as it is passed through the flame and calciner to an outlet. The residence time can be 20 seconds to 30 seconds, 1-3 minutes, less than 5 minutes in some embodiments. Some embodiments can facilitate calcination of a CaCO.sub.3 material so the calcined solid material output from a calciner is comprised of Ca(OH).sub.2 (e.g. is mostly Ca(OH).sub.2, is over 90 weight percent Ca(OH).sub.2, etc.).

The disclosure generally provides a modification of a calcination process of lime bearing sludge in such a way that the flue gas generated by the calcination process contains primarily carbon dioxide and water vapor along with only minor amounts of other gaseous species. Such a flue gas can be treated by standard industrial gas scrubbing and purification processes to remove residual particulate solids, to condense and remove the water vapor as liquid water, and further treatment to produce essentially pure carbon dioxide. The resulting product may be used for purposes that do not involve a net emission of carbon dioxide to the atmosphere, thereby reducing environmental harm. Such purified carbon dioxide may be used in industry for enhanced oil recovery (EOR) processes, synthetic fuels production, carbonated beverage production, pharmaceutical production, or other beneficial uses.

The disclosure generally provides a modification of a calcination process of lime bearing sludge in such a way that the flue gas generated by the calcination process contains primarily carbon dioxide and water vapor along with only minor amounts of other gaseous species. Such a flue gas can be treated by standard industrial gas scrubbing and purification processes to remove residual particulate solids, to condense and remove the water vapor as liquid water, and further treatment to produce essentially pure carbon dioxide. The resulting product may be used for purposes that do not involve a net emission of carbon dioxide to the atmosphere, thereby reducing environmental harm. Such purified carbon dioxide may be used in industry for enhanced oil recovery (EOR) processes, synthetic fuels production, carbonated beverage production, pharmaceutical production, or other beneficial uses.

A method for producing lime or dolime, which includes a calcination step for the calcination of calcareous or dolomitic material which is brought into contact with the first fumes which are obtained by combustion of fuel with an oxidizing gas, a cooling of calcined lime or dolime with discharge and collection thereof and a release of a gaseous effluent containing CO.sub.2. Subsequent processing steps result in the formation of a CaO-based sorbent material with separation between the CaO-based sorbent material and a CO.sub.2-concentrated gas stream which is collected. The recycling of said separated CaO-based sorbent material is recycled into a CO.sub.2 depletion step resulting in the extraction of a valorizable fraction of the CaCO.sub.3CaO based charge with a compensatory introduction of fresh CaCO.sub.3 in the calcination step.

A process and apparatus for manufacture of biocide products are described. The biocide properties arise from the caustic calcined powder, from carbonates such as such as magnesite and dolomite, and from hydroxides such as brucite. The method of manufacture is based on the production of high surface area oxide particles using an indirectly heated counterflow reactors for specifically calcining the carbonates and the hydroxides without significant sintering. The biocide products may be a powder or a hydrated slurry. A hydrated slurry is preferred for agricultural applications as a spray. For aquaculture applications, the products have a preferred particle size distribution to impact the aquatic and benthic ecosystems, and a Ca/Mg ratio that promotes the growth of the cultivates species when applied as a powder or a slurry. For applications such as a marine paint, the powder product or the slurry product is mixed with various agents to form a setting coating, and is applied to the infrastructure that is otherwise subject to biofilm growth.

Method of operating a long direct-fired inclined counterflow rotary kiln for the thermal treatment of material and counterflow rotary kiln adapted for same, whereby material to be treated is introduced into the kiln at the inlet end and treated material is evacuated from the kiln at the outlet end, whereby a main combustion zone extends inside the kiln over a distance of to of the internal length L.sub.int of the kiln, whereby a supplementary combustion zone in which supplementary combustion takes place with an oxygen-rich oxidant extends inside the kiln over a distance from the inlet end of at most of the internal length L.sub.int, and whereby no combustion takes place in a heat exchange zone located between the main combustion zone and the supplementary combustion zone.

An acid gas absorption composition may generally comprise calcium oxide generally characterized by a specific surface area from 40-100 m.sup.2/g, a porous volume from 0.25-0.50 cm.sup.3/g within a pore diameter range up to 1200 Angstroms, more than 40% by weight of the composition of pores having a diameter from 100-400 Angstroms, and an acid gas mass absorption capacity of at least 4.5 grams of acid gas per 100 grams of composition. Methods of making and using the same are also described.

Apparatus for the production of carbon dioxide from limestone includes a nuclear reactor (10) for generating heat and a rotary kiln (12). The rotary kiln (12) has an inlet (28) for the introduction of limestone and an outlet (30) for the release of carbon dioxide. A heat transfer arrangement is provided for transferring heat from the nuclear reactor (10) to the interior of the rotary kiln (12). The heat transfer arrangement includes feed and return primary conduits (17,18) for passing a heat transfer fluid (14) through the nuclear reactor (10) so that heat may be extracted from the nuclear reactor (10) for transfer to the interior of the rotary kiln (12). Limestone in the rotary kiln (12) is thereby heated to a temperature sufficient for the release of carbon dioxide.

Apparatus for the production of carbon dioxide from limestone includes a nuclear reactor (10) for generating heat and a rotary kiln (12). The rotary kiln (12) has an inlet (28) for the introduction of limestone and an outlet (30) for the release of carbon dioxide. A heat transfer arrangement is provided for transferring heat from the nuclear reactor (10) to the interior of the rotary kiln (12). The heat transfer arrangement includes feed and return primary conduits (17,18) for passing a heat transfer fluid (14) through the nuclear reactor (10) so that heat may be extracted from the nuclear reactor (10) for transfer to the interior of the rotary kiln (12). Limestone in the rotary kiln (12) is thereby heated to a temperature sufficient for the release of carbon dioxide.

The invention provides compositions and methods directed to carbonation of a cement mix during mixing. The carbonation may be controlled by one or more feedback mechanisms to adjust carbon dioxide delivery based on one or more characteristics of the mix or other aspects of the mixing operation.