Abstract: Systems and methods for impurity removal to limestone using modifications to the typical calcination process of turning calcium carbonate into calcium oxide prior to slaking to produce calcium hydroxide. 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.

Abstract: According to the invention, the method for burning fragmented material is carried out in at least one shaft which comprises a preheating zone, a combustion zone and a cooling zone, coal having a swelling index>1 being supplied via combustion lances, and the temperature of the coal in the combustion lances being maintained below a temperature value at which melting phases of the coal used are formed.

Abstract: This application concerns methods and apparatus for use in industrial waste recovery operations such as recovery of non-consumed chemicals in industrial processes, with recovery of quick lime in a wood pulp process being an example. In some embodiments, methods comprise baking lime sludge in a kiln and controlling a temperature in a calcining zone of the kiln to be above about 2250° F. to vaporize sodium contained in the lime sludge. Interaction of the vaporized sodium with SOx can deter accumulation of one or both of CaCO3 and CaSO4 on one or more inner surfaces of the kiln. In some embodiments, lime sludge can be rinsed to generate a filtrate comprising dissolved NaOH, and the filtrate can charge a scrubber for removing SOx from an exhaust from the kiln. Embodiments of co-fired burners for heating such kilns by burning petroleum coke and natural gas are also disclosed.

Abstract: A powder lime calcining process comprises: transporting fine granules of limestones having a water content less than 4%, and a granule size less than 15 mm, from a raw material storing bin to a small material bin, transporting the materials from the small material bin into an airflow pipe by a belt conveyer, heating and drying the materials, sieving the materials by a sieving device, transporting granules into a cyclone cylinder deduster and a clothbag deduster in turn by airflow pipes, the fine powders of limestones after dedusted are transported into an intermediate bin; the materials within the intermediate bin are transported to four preheating cyclone cylinders by a pneumatic lift pump and airflow pipes, and are preheated and separated; the materials after separated are transported into three cooling cyclone cylinders for cooling and separating the materials, finally transported into a finished product bin by a finished product transporting system.

Abstract: Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to aluminum ratio from about 0.25:1 to about 1:1.

Abstract: An air pollution control system 10A according to the present invention includes: a boiler 11 that burns fuel; NOx removal equipment 12 that decomposes nitrogen oxides in flue gas 25 discharged from the boiler 11; a desulfurizer 15 that causes sulfur oxides in the flue gas 25 having passed through the NOx removal equipment 12 to be absorbed by an absorbent, thereby reducing sulfur oxides in the flue gas 25, a waste-water treatment device 16 including a solid-liquid separating unit 31 that separates desulfurized waste water 28 discharged from the desulfurizer 15 into a solid fraction and a liquid fraction, and a mercury removing unit 32 that removes mercury in the desulfurized waste water 28; and a treated waste-water returning unit (a makeup water line) 17 that returns at least a part of treated waste water 40 treated by the waste-water treatment device 16 to the desulfurizer 15.

Abstract: The invention relates to the purification of recovered AB5 alloy which is obtained from spent nickel/metal hydride storage batteries by the selective removal of any Ni(OH)2 and the recovery of lanthanum without dissolving any AB5 alloy.

Abstract: Disclosed is a method for calcining a natural chalk powder within a rotary kiln. The powder is inserted into the kiln accompanied by an additive that promotes nodulization of the powder to thereby facilitate the treatment of the chalk powder within the rotary kiln. The nodulization takes place at temperatures less than the calcining temperatures of the chalk and prior to the nodulized chalk being calcined within the kiln.

Abstract: A method of making magnesium hydroxide may include calcining a mineral source of magnesium carbonate to form magnesium oxide, and slaking the magnesium oxide in water. When the mineral source of magnesium carbonate further includes a mineral source of calcium carbonate, the calcination may be carried out such that less than about 20 wt % calcium oxide is formed following calcining and prior to slaking in water.

Abstract: Disclosed herein are sorbents and devices for controlling sulfur oxides emissions as well as systems including such sorbents and devices. Also disclosed are methods for making and using the disclosed sorbents, devices and systems. In one embodiment the disclosed sorbents can be conveniently regenerated, such as under normal exhaust stream from a combustion engine, particularly a diesel engine. Accordingly, also disclosed are combustion vehicles equipped with sulfur dioxide emission control devices.

Abstract: A system and method for the calcination of minerals.

Abstract: Applying an acid treatment to eggshells provides a sorbent with unexpectedly high CO2 capture capacity and ability to regenerate.

Abstract: A system for fluidizing ash in a duct of a selective catalytic reduction system. The system includes a duct, a source for generating compressed air, and an air injection header joined with the source and joined with the duct via one or more holes in the duct. The air injection header is adapted to inject compressed air from the source to the areas of the duct prone to dust build-up. The air injection header includes a sub-header joined with a plurality of injection lances. Each of the plurality of injection lances has an end nozzle. The end nozzle may have a mushroom cap or an angled end configuration to direct air in a particular direction.

Abstract: A lime regeneration method and system of apparatus which compacts lime mud into agglomerates of predetermined configurations for improved handling and processing in a subsequent compact, efficient, minimally polluting and low cost reactor vessel in which the mud is dried, heated, calcined and cooled to form a reactive lime product.

Abstract: A method and plant for heat treatment of lime sludge (CaCO.sub.3) formed by the causticizing process during the manufacture of paper pulp. The lime sludge is dried and pulverized in a first process stage and preheated in a second process stage by means of hot exhaust gas coming from a kiln. In order to ensure that the temperature in the second process stage does not exceed a predetermined temperature lying within the range from 400.degree.-600.degree. C., the relationship between the amount of energy available in the exhaust gas for preheating in the second process stage and the amount of accumulated energy in the material which is to be preheated is regulated.

Abstract: Method and apparatus for obtaining finely pulverized quicklime powder having high reactivity by calcining fine limestone powder, particularly, of particle sizes 1-100 micrometers. Coarse particles of inert substance, particularly, those having diameters of 100-1500 micrometers, are fluidized with high temperature gas to form a fluidized bed, and fine limestone powder is supplied into the fluidized bed. The fine limestone powder captured by the fluidized bed is calcined therein and the resulting quicklime powder is carried away by the stream of fluidizing gas and recovered with cyclone and bag filter. Coarse limestone may be used instead of or together with the coarse inert substance particles.

Abstract: A process for calcining limestone to lime to produce a low sulfur content lime product, while combusting a sulfur-containing carbonaceous fuel in a rotary kiln to provide heat for the calcination. A finely divided lime hydrate is added to the rotary kiln adjacent the combustion flame, such that the lime hydrate particles react with sulfur-containing contaminants in the hot combustion gases to form lime hydrate-sulfur reaction products, such as calcium sulfate, which are retained in the gaseous flow and removed from the rotary kiln.

Abstract: Lime mud from kraft pulp recovery operations is processed using dielectric hysteresis heating, in a two-stage operation, in which wet lime mud first is dried then the dried lime mud is decomposed to lime and carbon dioxide. A two-zone lime mud calciner is employed in which the lime mud is conveyed horizontally, with drying being effected in the first zone and then decomposition being effected in the second zone. A co-current flow of purge air removes steam generated in the first zone and a counter-current flow of purge air removes carbon dioxide generated in the second zone.

Abstract: Disclosed is a method and an apparatus for the heat treatment of lime sludge (CaCO.sub.3) to form burnt lime (CaO). In the method of the present invention lime sludge is dried in a gas dryer means, to produce a dried lime sludge. The dried lime sludge is separated from the gases and thereafter is first fed to a compacting means wherein it is compacted into a plurality of substantially uniform bodies which are thereafter fed to a shaft kiln in which the compacted dried lime sludge is converted to active burnt lime.

Abstract: A process for the continuous production of a calcined product containing a high level of reactive oxide valves, from a preheated raw material containing calcium carbonate values, said process comprising,(a) introducing the preheated raw material to the bottom of a generally vertically oriented gas suspension calcining furnace, whereby said preheated raw material is thereafter suspended in an ascending stream of heated gas to thereby pass vertically upwardly through the gas suspension calcining furnace;(b) passing the ascending gas stream through a plurality of burners, into which fuel and air are injected, that are vertically spaced from each other, in the gas suspension furnace, at a number of levels in the flow direction of the heated gas, and(c) collecting the calcined product.

Abstract: This is a process and a device making use of a process for forming calcium oxide from pulverulent calcium carbonate, according to which an initial bath of pulverulent calcium oxide is produced in a reactor (1, 31) in the form of a fluidized bed which is heated electrically to a temperature higher than of the order of 900.degree. C., and the said pulverulent calcium carbonate is then introduced continuously into the bath while the temperature of the bath is always kept higher than of the order of 860.degree. C. by electrical heating, to dissociate the said calcium carbonate into calcium oxide and carbon dioxide.

Abstract: A method for calcination of a calcium carbonate material comprising heating the calcium carbonate material to a temperature and for a time sufficient to calcine the material to the degree desired while in the presence of a catalyst; said catalyst comprising at least one fused salt having the formulaMCO.sub.3.CaCO.sub.3.CaO.H.sub.2 O.sub.x,wherein M is an alkali metal and x is 0 to 1 and formed by fusing MCO.sub.3 and CaCO.sub.3 in a molar ratio of about 1:2 to 2:1, and a blend adapted to be heated to CaO comprising a calcium carbonate material and at least one such fused salt.

Abstract: Energy conserving limestone calcining system, including a process and apparatus in which in a first step or kiln zone limestone is heated, e.g., at 1700.degree.-2100.degree. F., sufficiently to achieve more than only about 50 or 60%, e.g.

Abstract: The invention relates to a process for the decarbonation of minerals, in powdered form, in a fluidized bed. For example, the process applies to the production of quick lime and/or magnesia from lime stone and/or dolomite fines which are not rendered sufficiently valuable at present.The process comprises recycling a portion at least of the carbon dioxide produced to be used as sole fluidizing gas, the fluidized bed being heated to the desired decarbonation temperature by direct heat supply within the fluidized bed by means of electric devices.Production of decarbonated minerals and of CO.sub.2.

Abstract: An already existing conventional lime production plant using a rotary kiln discharging directly into a rotary cooler, is converted reversibly to the production of dry hydrated lime by introducing water into contact with the lime in the cooler sufficient to hydrate the lime without requiring any significant change in the operating parameters of the lime production such as material throughput, cooling and combustion air supply rates and firing conditions.

Abstract: A process is disclosed for producing quicklime by a calcining treatment with a hot gas in a rotary kiln, wherein solid carbonaceous fuel for producing hot gas is fed into the charging end of the rotary kiln and an oxygen-containing gas is blown through nozzle blocks into the charge disposed over nozzle blocks in the heating-up zone beginning at the point where ignitable particles of the solid fuel first appear, the improvement wherein:(a) an oxygen-containing gas is blown through nozzle blocks into the charge disposed over nozzle blocks in that region of the heating-up zone which begins with the appearance of ignitable particles of the solid fuels and which ends where the temperature in the charge does not rise further;(b) oxygen-containing gases are blown through nozzle blocks into the charge disposed over nozzle blocks in a calcining zone which succeeds said heating-up zone and at such a rate that the temperature in the charge is held constant and for as long as the temperature remains constant,(c) oxygen-c

Abstract: Disclosed is a method of thermal treatment of a carbonate suspension yielding lime and CO.sub.2 -containing gas, such suspensions may be those resulting from a filtration sediment for sugar production, comprising in general the steps of dividing the carbonate suspension into two portions, spray-drying these portions both simultaneously and independently, calcining the material produced after suspension drying, cooling the lime produced after calcination, supplying the gas from the calcination zone for spray-drying the first portion of the suspension, withdrawing carbon dioxide recovery from the spent gas after spray-drying the first portion of the suspension, the calcination being carried out by means of the heat of the heat-carrier required for calcinating the material and spray-drying only the first portion of the suspension.

Abstract: A process for the calcining of limestone or hydrated lime by thermal treatment thereof with hot gases in a rotary kiln through which the kiln atmosphere and the charge are countercurrently passed, which kiln is fed with solid carbonaceous fuel, is described. The invention resides in introducing an oxygen-containing gas into a horizontal region across the rotary kiln defined by a point along the length of the kiln where ignitable particles of said solid fuel first appear and a second point along the length of said rotary kiln which is spaced from the charging end of said kiln not more than 50% of the length thereof. The oxygen-containing gases are injected through nozzle blocks in said rotary kiln, and oxygen-containing gas is introduced into the free space of said kiln.

Abstract: The sorbent capacity of calcium oxide with respect to sulfur dioxide is increased by calcining limestone or dolomite in an atmosphere where the partial pressure of carbon dioxide is greater than 40 percent of the equilibrium partial pressure of carbon dioxide over calcium carbonate at the reaction temperature. Where dolomite is the starting material, it may be calcined in a two-step heating process in which the atmosphere during the first heating stage contains carbon dioxide and the temperature is maintained in the dissociation range of magnesium carbonate (M.sub.g CO.sub.3); the atmosphere of the second heating stage also contains carbon dioxide, but the temperature is maintained in the calcium carbonate (CaCO.sub.3) dissociation range. Calcium oxide so produced in such an atmosphere of carbon dioxide sufficient to delay calcination is found to have relatively large mouthed pores capable of sorbing increased amounts of sulfur.

Abstract: A process for the calcining of limestone or hydrated lime by thermal treatment thereof with hot gases in an oxidizing atmosphere in a rotary kiln through which the kiln atmosphere and the charge are countercurrently passed, which kiln is fed with fuel from shell burners, is described. The invention resides in the use of different fuels which release different quantities of SO.sub.2 and SO.sub.3 per unit of calorific heat. The fuel which releases the larger quantity of SO.sub.2 or SO.sub.3 per unit value of calorific heat is supplied to the upper portion of the rotary kiln, and the fuel which releases the smaller quantity of SO.sub.2 and SO.sub.3 per unit of calorific heat is supplied to the lower portion of the rotary kiln.

Abstract: A process for the preparation of magnesium compounds from breunnerite or from mineral concentrates or tailings containing breunnerite in which the mineral is calcined and treated with an acid and the magnesium salt solution so formed is separated from insoluble matter.

Abstract: A process and installation for the production of powdered, surface-active agglomeratable, calcined material, specifically calcined lime, from material or raw material present in the form of sludge, scum or the like, such as the waste materials in the sugar industry. The specific example of the process is production of calcined lime and/or usable CO.sub.2 from waste materials existing in the sugar producing industry. The process includes reacting the raw materials in a special mixing chamber under controlled time and temperature conditions, preheating the materials by using the reaction exhaust gases, obtaining calcined lime particles isolated from CO.sub.2 gases, and recycling portions of the particles to obtain complete reaction of the material. The process provides calcined lime which can be discharged in solid form or converted through further stages to lime-milk for direct use in sugar making processes.

Abstract: Endothermic processes are carried out in a fluidized-bed reactor which is connected to a holding reactor, solids being recirculated between the two reactors. The primary fluidized-bed reactor uses a fast-fluidized bed system in which the solids concentration decreases continuously from the bottom to the top of the reactor. After the necessary residence time in the holding reactor, solids are discharged. Solids are entrained with the gas stream from the primary reactor and are separated therefrom to be delivered to the holding reactor. The reaction is controlled by regulating the rate of recirculation of solids from the holding reactor to the fast fluidized bed reactor.

Abstract: There is provided a process for stabilizing lime mud so as to eliminate balling during calcination of the same by incorporating a surface active agent decomposable at a temperature below 1500.degree. F into lime mud comprising calcium carbonate, filtering said treated lime mud, and thereafter calcining said treated lime mud to recover calcium oxide absent any balling during calcination.

Abstract: Reactive calcium oxide is produced on an industrial scale by decomposing calcium carbonate having a grain size of less than 200 .mu.m at a temperature of at least 850.degree. C and at a CO.sub.2 --partial pressure of not more than 40% of the CO.sub.2 --equilibrium pressure corresponding to the formation of the reactive calcium oxide.