| 摘要 |
A method of preparing physically united materials or chemical compounds in particulate form from one or more granular and/or pulverulent substances which are infusible or are incompletely fusible at the temperature at which the method is carried out and one or more gaseous, liquid or solid materials comprises introducing the gaseous, liquid or solid materials in a finely divided state into the core of one or more inert gas streams which is or are thereafter fed through the bottom portion of a mixing vessel having an expansion chamber communicating with the top thereof into a fluidized bed formed in said mixing vessel and comprising the granular and/or pulverulent substance or substances, the or each gas stream comprising, in addition to said core, a current of said gas surrounding the core and of lower velocity than said core, the gas stream or streams being such as to produce and maintain said fluidized bed and to draw said granular and/or pulverulent substance or substances from said fluidized bed into said core and the core of the or each gas stream having a velocity greater than the minimum velocity required to convey the granular and/or pulverulent substance or substances drawn thereinto clear of said fluidized bed into said expansion chamber wherein the velocity of said core is rapidly reduced to a value less than that required to maintain the movement of the physically united materials, or chemical compounds formed in the or each gas stream in an upward direction, the particle size of the finely divided gaseous, liquid or solid material or materials introduced into said core being regulated according to the desired size of the particles consisting of said physically united material or chemical compounds. Examples are given of coating particles of sand, to be used in forming moulds for casting metal, with thermosetting synthetic resin; the preparation of crystalline material from anhydrous materials such as anhydrous sodium carbonate or sodium polyphosphate; and bringing about the reaction between nitric acid, ammonia and lime marl in the manufacture of calcium ammonium nitrate, by placing the lime marl in a mixer and spraying ammonia and nitric acid thereinto. Specification 915,412 is referred to.ALSO:A method of preparing physically united materials or chemical compounds in particulate form from one or more granular and/or pulverulent substances which are infusible or are incompletely fusible at the temperature at which the method is carried out and one or more gaseous, liquid or solid materials comprises introducing the gaseous, liquid or solid materials in a finely divided state into the core of one or more inert gas streams which is or are thereafter fed through the bottom portion of a mixing vessel having an expansion chamber communicating with the top thereof into a fluidized bed formed in said, mixing vessel and comprising the granular and/or pulverulent substance or substances, the or each gas stream comprising, in addition to said core, a current of said gas surrounding the core and of lower velocity than said core, the gas stream or streams being such as to produce and maintain said fluidized bed and to draw said granular and/or pulverulent substance or substances from said fluidized bed into said core, and the core of the or each gas stream having a velocity greater than the minimum velocity required to convey the granular and/or pulverulent substance or substances drawn thereinto clear of said fluidized bed into said expansion chamber wherein the velocity of said core is rapidly reduced to a value less than that required to maintain the movement of the physically united materials, or chemical compounds formed in the or each gas stream in an upward direction, the particle size of the finely divided gaseous, liquid or solid material or materials introduced into said core being regulated according to the desired size of the particles consisting of said physically united materials or chemical compounds. Examples are given of coating particles of fat with milk powder; coating particles of molasses with meal to form cattle food; coating particles of sand, to be used in forming moulds for casting metal, with thermosetting synthetic resin; bringing about the absorption of water by dextrin with or without granulation of the product; the preparation of crystalline material from anhydrous materials such as anhydrous sodium carbonate or sodium polyphosphate; the absorption of water by milk powder; bringing about the reaction between nitric acid, ammonia and lime marl in the manufacture of calcium ammonium nitrate, by placing the lime marl in a mixer and spraying ammonia and nitric acid thereinto; and bringing about the chemical reaction between two immiscible liquids such as 2-chloroethanol and trimethylamine by introducing these into a loosened bed of a neutral carrier material and subsequently removing the compound formed from the carrier. Specification 915,412 is referred to. |
