Abstract: A method is shown for raising the pH of a cyanide leach solution of the type used in a heap leaching mining operation. Lime slurry is mixed with a side stream of barren cyanide solution in a reactor vessel in order to remove carbonate hardness, to regenerate the hydroxide alkalinity and to raise the pH of the resulting recausticized leach solution. A portion of the calcium carbonate precipitate formed in the reactor vessel is retained in order to encourage further crystal growth. Overflow from the reactor vessel passes through one or more cyclone separation stages in order to remove particulate solids. A cyclone overflow stream is directed back to the process to upwardly adjust the pH of the bulk of the barren cyanide solution. A cyclone underflow stream is directed back to the reactor vessel to provide seed crystal nuclei for precipitate growth.

Abstract: A method is shown for retarding the reactivity of quicklime. The quicklime is contacted with an aqueous solution of a boron-containing compound after being calcined. The boron-containing solution can be sprayed on the quicklime as it moves past on a conveyor belt. The retarded quicklime can be used for various industrial purposes and is especially useful as a reactant in a glass making operation.

Abstract: This invention relates to a method to further enhance NOx reduction in rotary preheater mineral kilns by coupling the temperature control and gas composition uniformity afforded by the high temperature mixing with the use of chemical reducing agents. The chemical reducing agent or agents, generally chosen from ammonia or ammonia precursors, are introduced at a specific point in the rotary preheater kiln which has as an optimal temperature window to achieve the greatest reduction of NOx emissions.

Abstract: A method is shown for producing food grade hydrated lime. A source of raw, hydrated lime is first passed through a classification step which divides the raw hydrated lime into a first fine stream and a first coarse stream. The first fine stream is passed through a further separation step and, without being recombined with the first coarse stream is separated out to form a very fine sized product which meets CODEX chemical specifications. The additional separation step may be a wet process and may utilize a hydrocyclone type separator.

Abstract: A method is shown for controlling the presence of soluble sulfate ions in a lime slaking operation in which a source of quicklime is combined with slaking water to form calcium hydroxide product. A complexing agent is added to either the quicklime or the slaking water which is effective to tie up the soluble sulfate ions otherwise available in solution, whereby the agglomeration of calcium hydroxide product is acceptably controlled.

Abstract: A method is shown for briquetting quicklime fines. A source of quicklime or dolomitic quicklime fines is combined with a binder in the form of a pseudo-plastic carbon containing material which will deform under briquetting conditions of elevated temperature and pressure and flow and which will also return to a solid phase and bind the quicklime fines upon cooling. An external force is applied to the mixture of fines and binder, as with a briquetting machine, sufficient to form the mixture into a briquette having requisite strength and durability characteristics. Suitable classes of carbon containing materials include Gilsonite®, a solid coal tar pitch and recycled plastics such as polyethylene and polypropylene.

Abstract: There is disclosed a method of selecting, in real time, a soil stabilizing protocol for clay-bearing soils occurring in construction sites. The method includes the steps of: obtaining soil conductivity data values at locations within a defined site without disturbing the surface of the soil; correlating the soil conductivity data values with corresponding estimates of soluble sulfate levels; recommending a calcium-based soil stabilizing protocol if the estimated level of soluble sulfates is less than a predetermined threshold; and performing a laboratory analysis of soil samples from selected portions of the defined site when the estimated soluble sulfate concentration equals or exceeds the predetermined threshold.

Abstract: A calcium hydroxide slurry is injected into the off gases in the exhaust duct of an industrial plant which burns sulfur containing fuels. The calcium hydroxide slurry reacts with SO3 produced as a result of the combustion process and forms a primary solid calcium sulfate reaction product. The calcium sulfate can then be removed in a particulate removal station in the plant.

Abstract: A method is shown for producing food grade hydrated lime. A source of raw, hydrated lime is first passed through a classification step which divides the raw hydrated lime into a first fine stream and a first coarse stream. The first coarse stream is then passed to a grinder which produces a ground coarse product. The first fine stream is separated out from the first coarse stream and, without combining the first fine stream with the first coarse stream or with the ground coarse product, is removed to produce a very fine sized product which meets CODEX chemical specifications.

Abstract: A calcium hydroxide slurry is injected into the off gases in the exhaust duct of an industrial plant which burns sulfur containing fuels. The calcium hydroxide slurry reacts with SO3 produced as a result of the combustion process and forms a primary solid calcium sulfate reaction product. The calcium sulfate can then be removed in a particulate removal station in the plant.

Abstract: The present invention is a single-entity lime slurry reactor for production and delivery of lime slurry to remote jobsites. The reactor includes a tank body with an interior surface which forms a mixing chamber. The tank is coupled to a unitary frame and rests substantially parallel to the ground. A pair of spaced apart inlets located on the tank allow the delivery of solid lime to the tank from a carrier parked next to the apparatus. Power units are attached to the device in order to make it self-contained. A rotatable outlet allows slurry to be discharged to a tanker truck or other carrier. A vertical placement device is used for placing the frame, tank body, and power unit in a working position once at a jobsite and a raised position when pulling the apparatus on a highway.

Abstract: A method for manufacturing an aerated autoclaved concrete material. A quick-stiffening mixture is prepared by combining a silica containing material, quicklime, a rising agent, gypsum, cement and water. The mixture is deposited into a mold and is allowed to form a stiffened body. The stiffened body is removed from the mold and placed in an autoclave station in which it is steam cured at elevated temperature and pressure. The quicklime which is used to form the quick-stiffening mixture is modified with a chemical modifier to provide a desired degree of chemical reactivity in the quick-stiffening mixture.

Abstract: The present invention is directed towards a method of preventing fine particles, especially liming material, from becoming air borne, and the addition of desirable chemical compounds to the particles. The method comprises feeding fine particles of solid to an enclosed inclined chute and locating at least a first inclined shelf and a subsequent inclined shelf within the chute, each shelf having an inclined top surface, a bottom surface and a leading edge. At least one liquid fog nozzle is located between the bottom surface of the first shelf and the chute, the fog nozzle creating a fog of liquid in the direction of the leading edge of the first shelf. Once the particles fall from the shelf, a fog is applied to the particles as the vertical free flow of particles falls from the leading edge of the first shelf. The inclined positioning of the chute allows gravity to pull the once coated particles to at least a second inclined shelf.

Abstract: A hot mix asphalt composition and method are shown in which hydrated lime is added directly to the asphalt binder prior to the addition of the asphalt binder to the mineral aggregate constituent of the composition. The lime-asphalt mixture is then added to the mineral aggregate. The lime component is added to the asphalt binder in an amount which exceeds about 10% by weight, based upon the total weight of asphalt binder in the composition.

Abstract: A flowable fill composition is shown which is prepared by mixing together a lime component, a pozzolanic component, aggregate material and water. The composition has a set compressive strength after 28 days of 2000 psi or less and is characterized by the substantial absence of cement or other self-setting adhesive components.

Abstract: Flue gases exhausted from a lime kiln containing lime kiln dust are treated to produce a high purity calcium carbonate precipitate. This is accomplished by passing the flue gases from the lime kiln through a kiln dust separator so that lime kiln dust containing calcium oxide is removed from the remaining flue gas. The lime kiln dust is mixed with water so that an aqueous suspension of the lime kiln dust is formed. Quicklime or calcium oxide in the lime kiln dust is thus hydrated to form calcium hydroxide. The solids within the suspension are then allowed to settle so that a clear, saturated solution of calcium hydroxide having a pH of about 12.4 is formed. This solution is then contacted with carbon dioxide gas so that the calcium hydroxide reacts to form a high purity calcium carbonate precipitate. This high purity calcium carbonate precipitate is then allowed to settle from supernatant water of the solution.

Abstract: A rotary reactor is shown having an improved internal lining including a lifter section which extends along an interior surface of the reactor chamber for lifting material from a lower portion of the chamber to an upper portion thereof as the chamber rotates. The lifter section is formed as a monolithic casting of a refractory material having a polygonal cross-section which includes a series of blunt faces alternating with a series of slanted faces. The slanted faces are aligned with a direction of rotation of the reactor such that the slanted faces of the refractory material first contact the material being lifted.

Abstract: A high temperature furnace and method for thermally decomposing solid combustible fuels into usable products to provide a source of heat to a selected area is disclosed. Solid combustible fuel, such as waste automobile tires, are introduced into a reaction vessel or combustion chamber which is defined by an outer wall. The reaction vessel has an upper portion and a lower portion with a central partition dividing the lower portion into compartments. Each compartment holds a fuel bed having a selected height wherein the sold fuel accumulates as it is being decomposed. Each compartment also has a bottom opening. Air ducts located along the outer wall of the reaction vessel and in the central partition supply pressurized air to the interior of the reaction vessel. An exhaust duct which communicates with the upper portion of the reaction vessel is supplied for venting off combustion or pyrolysis products from the reaction vessel to the selected area.

Abstract: A method of treating concrete pipe is carried out by providing an aqueous lime slurry supply having a lime solids content above 35% by weight of the slurry. This is mixed within an amount of dispersing agent and may contain an alkali metal hydroxide so that the slurry has a pumpable viscosity. A spray assembly is located within the interior of the pipe. The lime slurry is pumped from this lime slurry supply through the spray assembly so that the lime slurry is applied to the interior surfaces of the pipe to neutralize acids thereon. Applying the lime spray also provides a protective coating of the lime slurry on the interior surfaces of the pipe.

Abstract: A composition for a pumpable lime slurry which is adapted for use as a replacement for caustic solutions is formed by combining a dispersing agent in lime and water to form an aqueous slurry. The amount of lime used is between 35 to 55% by weight of the slurry. The dispersing agent, which is an anionic polyelectrolyte, such as polyacrylic, polycarboxylic acids and alkali metal salts thereof, is added in the an amount between 0.1 to 3% by weight of the lime. To this is added an alkali metal hydroxide of 0.1 to 1.5% by weight of lime. The order of addition of the alkali metal hydroxide is important. The later addition of the alkali metal hydroxide results in a decreased viscosity so that a lower amount of dispersing agent is required.