Process for manufacturing a milk of lime of great fineness comprising at least the steps of providing one lime compound and forming said milk of lime with a process water and said lime compound.

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

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.

An arrangement for burning lime mud into lime in a lime kiln. The lime mud flows counter-currently to flue gases from a feed end to a firing end and the fuel used is flue gas that is produced by gasifying a fuel in the presence of combustion air in a gasifier. The combustion air for gasification is preheated with heat generated in lime mud combustion. The arrangement is provided with a conduit between the lime kiln and the gasifier for leading air from the lime kiln into the gasifier as combustion air. At least a portion of the combustion air for gasification is preheated with heat generated in the lime mud combustion so that air is led into cooling of lime obtained in the combustion and further into the kiln, from or through the firing end of which air is taken into the gasification.

An arrangement for burning lime mud into lime in a lime kiln. The lime mud flows counter-currently to flue gases from a feed end to a firing end and the fuel used is flue gas that is produced by gasifying a fuel in the presence of combustion air in a gasifier. The combustion air for gasification is preheated with heat generated in lime mud combustion. The arrangement is provided with a conduit between the lime kiln and the gasifier for leading air from the lime kiln into the gasifier as combustion air. At least a portion of the combustion air for gasification is preheated with heat generated in the lime mud combustion so that air is led into cooling of lime obtained in the combustion and further into the kiln, from or through the firing end of which air is taken into the gasification.

The instant disclosure sets forth a process for re-activating a mineral residue. The process includes providing a mineral residue, which includes a core and a shell around the core. In certain examples, the core comprises calcium (Ca), magnesium (Mg), or a combination thereof. The Ca and Mg is not present as elemental Ca or Mg but rather as a compound of Ca or of Mg, such as but not limited to Ca(OH).sub.2 or Mg(OH).sub.2. In certain examples, the shell comprises an oxide, a hydroxide, a carbonate, a silicate, a sulfite, a sulfate, a chloride, a nitrate, or nitrite, of calcium (Ca) or of magnesium (Mg), or a combination thereof. The process includes (a) fractionating the mineral residue; (b) contacting the mineral residue with an acid and fractionating the mineral residue; or (c) contacting the mineral residue with a base and fractionating the mineral residue. As a result, the mineral residue's core is exposed. In some examples, the shell is passivating and inhibits the Ca or Mg, or both, in the core from reacting with carbon dioxide (CO.sub.2). By exposing the core as described herein, a mineral residue's reactivity with carbon dioxide is increased.

In an aspect, provided herein are methods for producing sulfuric acid and hydrogen gas, the methods comprising steps of: providing sulfur dioxide formed by thermal conversion of a sulfur-containing species; electrochemically oxidizing said sulfur dioxide to sulfuric acid in the presence of water; and electrochemically forming hydrogen gas via a reduction reaction. In some embodiments, the methods comprise a step of thermally converting said sulfur-containing species to said sulfur dioxide. Systems configured to perform these methods are also disclosed herein. Also provided herein are methods and systems for producing sulfuric acid and hydrogen gas by electrochemically forming the sulfuric acid and the hydrogen gas in a mixture comprising a sulfur material, a supporting acid, and water. Also provided herein are methods and systems for producing a cement material.

The present invention discloses the systems of producing calcium and magnesium carbonate from the Ca/Mg containing solution leached by a CO.sub.2-based hydrometallurgical process which includes: a precipitation reactor that the Ca/Mg containing leached solution is continuously added and fully mixed with the alkaline reagent at specific mole ratio into the precipitation reactor and the reactor also comprises a CO.sub.2 bubbling module where CO.sub.2 is captured and recirculated from the thermal decomposition process as needed; a solid-liquid separation unit that the treated slurry is treated by the solid-liquid separation unit to produce precipitated calcium and magnesium carbonate products where the recirculating water is recycled back into the precipitation reactor; a thermal decomposition unit that the calcium and magnesium carbonate products is calcined by the thermal decomposition unit to produce an alkaline reagent and the alkaline reagent is recycled back into the precipitation reactor for the next batch of reaction.

This invention relates to manufacturing briquettes, pellets and shapes from recycled asphaltic limestone powder derived from waste residential roofing products. Briquettes and pellets are manufactured through a densification process at varying temperatures, creating recycled asphalt pellets, asphalt limestone pellets and bio mass and coal fines briquettes. Various shapes, including curbs and posts, are manufactured through heat and pressure in molds. Seawalls, walkways and wall panels are manufactured by blending asphaltic limestone powders with polymer resins and extruded or pultruded into shapes.

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.