Abstract: A regenerative shaft furnace for burning carbonate-containing raw materials is disclosed having two or more shafts which are interconnected by ducts which operate in an alternate manner and wherein the burned raw material is cooled in the cooling zone of the shafts. Having a displacer in the cooling zone to prevent the reabsorption of carbon dioxide in the fuel gases by the burned material. A method for burning carbonate-containing raw material is also disclosed.

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 of making a calcium acetate-containing solution having a pH value at room temperature between about 7 and about 8 is provided comprising reacting acetic acid with a carbonate compound, adding calcined limestone, and optionally finishing off the acid-base reaction with an amount of an alkali metal hydroxide comprising from about 2% to about 5% of the total stoichiometric complement to the amount of acetic acid. Further process options which may be used in the preparation of deicing agents include adding coarse limestone to the above-prepared calcium acetate-containing solution in amounts up to 10% by weight and converting the solution into solid flakes.

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: This invention relates to hydroxyapatite, ceramic material, implant material and a process for preparing thereof. The ceramic material is hydroxyapatite ceramic having an excellent thermal stability.

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: Either sulphur-containing raw materials or sulphur-containing fuels may be used in the calcination of mineral raw materials in a calcining furnace, with significant desulphurization of the calcined material being achieved if, on the one hand, cooling air introduced into the cooling zone of the furnace is removed at the upper end of the cooling zone thereof through exhaust ducts and if, on the other hand, the flue gases are free of oxygen and have a carbon monoxide content of 1 to 5% by volume. In order to obtain this composition of the flue gases, the combustion process can either be performed in the calcining zone of the calcining shaft of the furnace with a deficiency of air or a gaseous, liquid or solid fuel can be supplied by means of fuel tubes located at a transfer duct between the furnace shafts.

Abstract: Process for the burning of lime, cement or other lumpy bulk materials in a shaft kiln using coal. Coal dust or particulated dry coal is continuously fed into a gasification chamber positioned in the center of the shaft kiln and is therein partially or fully gasified by the addition of air in substoichiometric proportions. The partially or fully gasified fuel is mixed with air at an elevated temperature. Such mixture is then burned in the burning zone of the shaft kiln. The flow of the heating medium, i.e., the burnt fuel, and the flow of the kiln charge are co-current within the kiln. The shaft kiln has a centrally postioned gasification chamber which is mounted on radial supports which are positioned in the shaft kiln in such a way as to produce a space below the supports. The space is substantially free from kiln charge. Uniform distribution of the gases is guaranteed across the cross section of the shaft kiln by the space.

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: In the regeneration of alkaline liquors as used in paper pulping, a mixed oxide compound of an alkali or alkaline earth metal oxide and an oxide of Ti, Fe, Co, Ni, or Mn is formed by burning black liquor. The burning step is carried out in a fluidized bed. The mixed oxide product is washed in cold water and subsequently treated with hot water to precipitate the oxide of Ti, Fe, Co, Ni or Mn and enable recovery of the alkaline solution for recycling.

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: This invention relates to a countercurrent combustion method and apparatus for the production of calcined lime in a furnace which contains, in sequence, at least one preheating zone, combustion zone, and a cooling zone. The entire combustion air is passed through the cooling zone thereby to preheat the same. A portion of the thus preheated air is withdrawn from the furnace and heated in a recuperation zone which may be within or outside the vertical shaft furnace but is located between the preheating zone and the combustion zone. In the recuperation zone, the air is heated to approximately the deacidification temperature and then is supplied to the combustion zone.

Abstract: A method and apparatus for calcining limestone in which limestone is burned continuously in a vertical kiln provided with at least one fuel injector which permits pulsed introduction of fuel thereto. Combustion air is passed continuously through the kiln and air/fuel mixing efficiency is enhanced by the use of an arch or hood superposed above the fuel injectors to thereby create a protected space in the mass of charged limestone.

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: A method for removing hydrogen sulfide from a hydrogen sulfide entrained gas comprises the steps of bringing the hydrogen sulfide entrained gas into contact with an alkaline absorption solution with a pH of 10 to 14 to cause hydrogen sulfide in the gas to be absorbed into an alkaline absorption solution, subjecting the resultant absorption solution to a DC electrolytic treatment whereby an alkaline solution is separated into a cathode chamber and sulfur and sulfuric acid are separated into an anode chamber, and circulating as the alkaline absorption solution the alkaline solution produced within the cathode chamber. This constitutes a closed system, thereby completely eliminating a cause for public nuisance.

Abstract: A process and apparatus for burning limestone to produce calcined lime in which limestone is burned continuously in a vertical kiln provided with a plurality of fuel injectors which permit pulsed introduction of fuel so as to ensure a lamellar flow of fuel through the kiln and a controlled release of heat.

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.

Abstract: Magnesia of very high purity is produced industrially from a magnesite waste material wherein impurities are present in such amounts that the weight ratio of the precipitable hydroxide ions, calculated as the sum of Fe.sub.2 O.sub.3 + Al.sub.2 O.sub.3 + Cr.sub.2 O.sub.3 + Mn.sub.3 O.sub.4 to the sum of SiO.sub.2 + TiO.sub.2 + B.sub.2 O.sub.3, is at least 1 : 3. The starting material is dissolved in hydrochloric acid of 15-32% concentration, the impurities are precipitated by adjusting the pH of the acidic solution to 4 - 9, and the purified magnesium chloride solution is thermally decomposed into magnesia and hydrochloric acid gas, the latter being recycled to form the hydrochloric acid of the stated concentration for dissolving the starting material.