The present invention relates to the technical field of steel slag solid waste utilization, and in particular to a method for selective extraction of calcium and secondary magnetic separation of iron from steel slag, comprising the following steps: adding a leaching agent into steel slag, controlling the leaching temperature to be 95-125℃ and the pH of a leaching system to 5.5-8, and continuously leaching calcium for 0.5-2 h; in the process of leaching the calcium or after the leaching of the calcium is finished, adding an oxidizing agent into a reaction system, and oxidizing part of the original non-magnetic ferrous oxide in the steel slag into magnetic ferroferric oxide; and performing magnetic separation on residues obtained after leaching to obtain magnetically separated powder having a total iron content of greater than 40% and tailing powder having an iron oxide content of greater than 40%. According to the method, calcium in the steel slag can be efficiently and selectively extracted, and a steel slag ore phase can be changed while the calcium is extracted, so that most of iron in the residues obtained after leaching can be enriched by magnetic separation again, thereby realizing grading and efficient utilization of calcium and iron elements in the steel slag, and improving the recycling rate of the iron.
222 absorption mineralization to obtain crude calcium carbonate and an ammonium chloride solution; and leaching the iron-aluminum precipitate residue by using a sodium hydroxide solution to separate the elements iron and aluminum. The method can achieve the efficient extraction and separation of main elements in steelmaking slag while achieving carbon reduction, and the auxiliary agent can be recycled. The process is simple, and the production cost is low, facilitating industrial production.
The present invention relates to the technical field of steel slag treatment devices, and in particular to a slag reactor and a slag treatment method. The slag reactor comprises a rack, a horizontal cylinder, a feeding mechanism, a discharging mechanism and a transmission mechanism; the horizontal cylinder is rotatably arranged on the rack by means of the transmission mechanism, and the feeding mechanism and the discharging mechanism are oppositely arranged at two ends of the horizontal cylinder in the axial direction of the horizontal cylinder and are communicated with the horizontal cylinder respectively; a plurality of spikes and a plurality of baffle plates are arranged on the inner side wall of the horizontal cylinder, the spikes are annularly and uniformly distributed along the inner side wall of the horizontal cylinder, and the baffle plates are arranged on the inner side wall of the horizontal cylinder in a staggered manner. According to the slag reactor of the present invention, the dispersion effect of a mixed slurry is improved, the generation of an inert layer on the surfaces of particles in a leaching process is avoided, the probability that an extraction solution diffuses to the surfaces of the particles is increased, and the element leaching efficiency is improved. The reactor has a simple structure, is easy for industrial scale-up, and has considerable prospects in the aspect of large-scale industrial production.
Disclosed is a method for preparing ammonia gas through a reaction between an ammonium salt and a silicate. An aqueous solution of the ammonium salt in the form of atomized droplets is contacted with a silicate at a high temperature for a reaction to generate ammonia gas and a solid substance. The silicate can be solid particles, and forms a bed. The generated ammonia gas is collected, the solid substance is extracted, part of the same solid substance is mixed with a fresh silicate solid particle, and the mixture continuously reacts with the atomized droplets of the aqueous solution of the ammonium salt.
Provided is a system and a method for preparing ultrafine silica by leaching silicate ore using hydrogen chloride gas, comprising an ore raw material feeding device, an ejector, a stirring tank and a liquid-solid separation device. A circulated material outlet of a stirred tank is connected with a liquid inlet of an ejector through a circulation pipe; a liquid outlet of the ejector is connected with a circulated material inlet of the stirred tank; a material outlet of a raw ore feeding apparatus is connected with the circulation pipe; and the circulated material outlet of the stirred tank is connected with a solid-liquid separation apparatus. Based on the system and method in the present disclosure, an industrially feasible solution for preparing silica by continuously leaching a silicate ore is provided. The dissolution efficiency of ores and the utilization of hydrochloric acid are greatly increased.
B01D 21/26 - Separation of sediment aided by centrifugal force
B01D 36/00 - Filter circuits or combinations of filters with other separating devices
C01B 33/193 - Preparation of finely divided silica neither in sol nor in gel formAfter-treatment thereof by acidic treatment of silicates of aqueous solutions of silicates
6.
PREPARATION DEVICE AND PREPARATION METHOD OF AMMONIA GAS
Disclosed are a preparation device and a preparation method of ammonia gas. The preparation device, prepares ammonia gas by reacting ammonium chloride with a particulate inorganic salt, includes one fluidized bed reactor with at least two fluidization chambers, in which one is a preheating chamber configured to preheat the particulate inorganic salt, and the other is a reaction chamber inside provided with at least one atomizing nozzle, the particulate inorganic salt forming a fluidized bed layer and reacting with an aqueous solution of ammonium chloride in the reaction chamber to generate the ammonia gas. The particulate inorganic salt can be sequentially flowed through a plurality of preheating chambers and reaction chambers under an impetus of a density difference of the particulate bed layers, finally achieving the required conversion rate.
B01J 8/18 - Chemical or physical processes in general, conducted in the presence of fluids and solid particlesApparatus for such processes with fluidised particles
7.
METHOD AND SYSTEM FOR PREPARING HYDROGEN CHLORIDE AND AMMONIA GAS BY USING AMMONIUM CHLORIDE
Disclosed is a system and method for preparing hydrogen chloride and ammonia gas by using ammonium chloride. The system includes a decomposition reactor and at least one regeneration reactor, or includes a reactor that may serve as the decomposition reactor and the regeneration reactor; ammonium chloride in particle form is continuously added to the decomposition reactor via a solid particle feed apparatus, and reacts with molten-state ammonium hydrogen sulfate to generate hydrogen chloride gas and an intermediate material; the intermediate material is discharged to the regeneration reactor, and heated therein to decompose into ammonium hydrogen sulfate and ammonia gas; and the ammonium hydrogen sulfate is returned to the decomposition reactor for recycling. The present disclosure provides an industrial feasible implementation solution for continuous decomposition of ammonium chloride, lowers volatilization of ammonium chloride by continuously and slowly adding ammonium chloride in particle form, and improves utilization rate of the ammonium chloride.
Disclosed are a method and a system for recycling carbon dioxide. The method includes chlorinating a calcium-containing silicate and/or a magnesium-containing silicate to obtain a calcium chloride and/or magnesium chloride, mixing the calcium chloride and/or magnesium chloride with ammonia water and carbon dioxide and performing a carbonation reaction to recover the carbon dioxide and convert it into calcium carbonate and/or magnesium carbonate while generating an ammonium chloride solution, and recovering the ammonium chloride solution generated in the carbonation reaction. The ammonium chloride solution after being concentrated or hydrogen chloride generated from a decomposition reaction of the ammonium chloride solution is directly used to chlorinate the calcium-containing silicate and/or the magnesium-containing silicate. The ammonium chloride is used as a catalyst for the entire mineralization of the carbon dioxide, the final product is the calcium carbonate and/or the magnesium carbonate.
Provided is a system for preparing silica by leaching silicate ore using hydrogen chloride gas, comprising an ore raw material feeding device, an ejector (4), a stirring tank (6) and a liquid-solid separation device (7); a material circulating outlet of the stirring tank (6) is in communication with a liquid inlet of the ejector (4) by means of a circulating pipeline; a liquid outlet of the ejector (4) is in communication with a material circulating inlet of the stirring tank (6); a material outlet of the raw material feeding device is in communication with the circulating pipeline; a circulating pump (5) is provided on the circulating pipeline; and the material circulating outlet of the stirring tank is in communication with the liquid-solid separation device (7). Further provided is a method for preparing silica from silicate ore powder and hydrogen chloride gas by using the described system. The described system and method provide a feasible industrialized solution for preparing silica by means of the continuous leaching of silicate ore. By means of using an ejector and employing a means of directly dissolving hydrogen chloride gas in a silicate circulating slurry, due to the initial contact between the slurry having high concentration and high dispersion in the ejector and a hydrochloric acid solution having a high concentration, the dissolution efficiency of the ore and the utilization rate of hydrochloric acid are improved.
C01B 33/193 - Preparation of finely divided silica neither in sol nor in gel formAfter-treatment thereof by acidic treatment of silicates of aqueous solutions of silicates
10.
METHOD FOR PREPARING AMMONIA BY USING AMMONIUM SALT AND SILICATE
Provided is a method for preparing ammonia by reacting an ammonium salt with a silicate, comprising contacting an aqueous ammonium salt solution in the form of atomized droplets with a silicate at a high temperature for a reaction to produce ammonia and a solid material, and collecting the ammonia produced. The silicate can be solid particles, and forms a bed. The solid substance produced during the reaction is taken out, and part of same is mixed with fresh silicate solid particles, and continues to react with atomized droplets of an aqueous ammonium salt solution. In this method, only a one-step reaction is needed in the preparation device to obtain ammonia, thus simplifying the reaction steps, reducing the difficulty of operation, and being easy for industrialized production.
Provided are an ammonia preparation device and a preparation method thereof. The preparation device is used for preparing ammonia by reacting ammonium chloride and granular inorganic silicate, including a fluidized bed reactor (10), the fluidized bed reactor (10) has at least two fluidized chambers, wherein one of the fluidized chambers is a preheating chamber (11) for heating the bed layer formed by granular inorganic salt, the other of the fluidized chambers is a reaction chamber (12), at least one atomizing nozzle is arranged inside the reaction chamber (12). The preparation method includes preheating the fluidized bed layer formed by the granular inorganic salt through the preheating chamber (11), then the particles can flow through the preheating chamber and the reaction chamber in sequence under the impetus of the density difference of the bed layer, and react with the ammonium chloride aqueous solution sprayed through the atomizing nozzle to generate ammonia in the reaction chamber. The device and method propose the idea of preparing ammonia using ammonium chloride, which simplifies the reaction steps and improves the reaction efficiency.
Provided are a system and method for preparing hydrogen chloride and ammonia gas using ammonium chloride. The system comprises at least one decomposition reactor and at least one regeneration reactor, or comprises a reactor which can be used either as a decomposition reactor or as a regeneration reactor. The method comprises: continuously adding ammonium chloride particles into the decomposition reactor through a solid particle feeding device on the reactor for reaction with ammonium bisulfate in a molten state to generate hydrogen chloride gas and intermediate materials, discharging the intermediate materials into the regeneration reactor for heating and decomposition to form ammonium bisulfate and ammonia gas, returning the ammonium bisulfate to the decomposition reactor for cycle use; or, when a single reactor is used, heating added ammonium chloride particles to a decomposition reaction temperature until hydrogen chloride is completely generated, further heating the reactor up to the regeneration reaction temperature to generate ammonia gas until the reaction is complete. According to the method, the ammonium chloride solid particles are continuously and slowly added, thereby reducing the volatility of ammonium chloride and improving the utilization rate of ammonium chloride.
A method and a system for recycling carbon dioxide. The method for recycling carbon dioxide comprises: chlorinating a calcium-containing silicate and/or a magnesium-containing silicate to obtain calcium chloride and/or magnesium chloride; mixing the calcium chloride and/or magnesium chloride with ammonia water and carbon dioxide and conducting a carbonation reaction to recycle and convert the carbon dioxide into calcium carbonate and/or magnesium carbonate and produce an ammonium chloride solution; and recycling the ammonium chloride solution produced by the carbonation step, and generating hydrogen chloride after decomposition or directly using the ammonium chloride solution after concentration to chlorinate the calcium-containing silicate and/or magnesium-containing silicate. The process uses ammonium chloride as a catalyst for an overall carbon dioxide mineralization reaction and produces a final product of calcium carbonate and/or magnesium carbonate having high purity with low energy consumption. The process realizes circulative use of ammonium chloride, and reduces material consumption as compared with the prior art.
A method of utilizing construction and demolition waste is disclosed. The method comprises pretreating the construction and demolition waste into particles with a predetermined range of size; and obtaining calcium carbonate from the particles. The method of the present invention enables to recycle a wide range of construction and demolition waste, furthermore it can convert these waste materials into the high purity calcium carbonate which can be widely used in many applications.
Provided are a carbon dioxide absorption and mineralization device and method. The device comprises a reactor (1) and a three-phase separator (2). The reactor (1) comprises a tower body (11) and a flow guiding cylinder (12), wherein the flow guiding cylinder (12) is arranged inside the tower body (11). A liquid inlet pipe (13) and an air inlet pipe (14) are arranged on the tower body (11), wherein an outlet end of the liquid inlet pipe (13) and an outlet end of the air inlet pipe (14) are located inside the flow guiding cylinder (12). The flow inside the reactor is an air-lift circumfluent flow. The three-phase separator (2) is arranged at the upper end of the reactor (1), and comprises a riser pipe (22), a downspout (23) and a settling tank (27), wherein a carbonate is settled and separated while the reaction is performed. The method comprises absorbing and mineralizing carbon dioxide by an alkaline solution by using the device.
The present invention relates to an apparatus for absorbing and mineralizing carbon dioxide comprising a reactor and a three-phase separator, in which said reactor comprises a tower body and a draft tube disposed inside the tower body, a liquid inlet pipe and a gas intake pipe being disposed on the tower body, the outlet ends of the liquid inlet pipe and the gas intake pipe both being located inside the draft tube; and the three-phase separator is disposed at the upper end of the reactor, and a method therefor. The arrangement of draft tube inside the reactor of the present invention, enhances gas-liquid-solid mixing state because of the flow with airlift loop flow inside the reactor, accelerates the dissolution rate of solid alkali solute and thus may increase absorption reaction rate and absorptivity; the integration of three-phase separator in the reaction apparatus may isolate carbonate by settling while reacting, reduce solid content of the solution, while reducing the circulation of water between absorption and separation units, improve process performance, reduce process energy consumption; carbonate particles generated can be controlled better, thus a higher settling efficiency can be obtained.
B01D 53/14 - Separation of gases or vapoursRecovering vapours of volatile solvents from gasesChemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases or aerosols by absorption
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