摘要:
There is provided a flash activated hydrotalcite which, when extruded to sizes of about 1/16 inch or more, has a crush load strength of at least about 7 pounds. The process for making this extrudate includes: (a) providing a hydrotalcite compound; (b) heating said compound for less than two seconds to one or more temperatures above about 482.degree. C. (900.degree. F.); (c) cooling said heated compound; (d) collecting said cooled compound; (e) forming said compound into an extrudate; and (f) reactivating said extrudate by heating to one or more temperatures above about 400.degree. C. (752.degree. F.) for about 20 minutes or more. Further strength improvements are achieved by exposing these extrudates to steam for at least about 8 hours prior to step (f).
摘要:
An improved process for the production of concentrated, high-grade, nitrogen-phosphate (N--P.sub.2 O.sub.5) base suspension fertilizer from wet-process or other phosphoric acids and ammonia. The process involves addition of small proportions of fluosilicic acid during preparation of the suspension to cause modification of monoammonium phosphate crystals to shapes and sizes that do not settle during vibration such as occurs during shipment.
摘要:
an improved process for production of concentrated high-analysis nitrogen-phosphate base suspension fertilizer by ammoniation of wet-process or other orthophosphoric acids in two stages. The process improvement involves the addition of a small amount (0.1-0.5 percent) of a crystal modifier, fluosilicic acid, for prevention of settling of crystals in the suspension during vibration such as that which occurs during shipment. With use of the crystal modifier, the monoammonium phosphate crystals formed are small and needlelike, and suspension fertilizers with excellent shipping, storage, and handling properties are produced with an N:P.sub.2 O.sub.5 weight ratio in the range of highest solubility, about 0.27 to 0.33.
摘要:
A method for extrusion coating both sides of a metal strip. A metal strip, such as aluminum alloy strip, is moved through a pre-conditioner, two extrusion dies, a post heater and a cooling system. Both sides of the strip are coated with thin coatings of polyester material. The coated metal strip is useful for containers, such as cans and can ends, as well as for automobiles, appliances, aerospace, construction and electrical devices.
摘要:
Crystalline urea phosphate mixed with sufficient quantities of previously produced urea-ammonium polyphosphate liquid to provide fluidity is pyrolyzed batchwise in one stage to give molten urea ammonium polyphosphate containing up to 50 percent of the phosphate as polyphosphate. Water or aqua ammonia can be substituted for the polyphosphate liquid if certain prescribed steps in proper sequence are followed. Heat from ammoniation of the urea phosphate provides all of the heat for pyroloysis. The molten urea-ammonium polyphosphate is then processed into high-analysis liquid fertilizer.
摘要:
There is provided a method for making monovalent organic anion-intercalated hydrotalcite-like materials by first reacting a magnesium-containing powder and a transition alumina powder in a carboxylic acid-free, aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a monovalent organic anion to form a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include a stearate-, acetate- or benzoate-intercalated hydrotalcite-like material.
摘要:
There is provided an improved method for making synthetic hydrotalcite by first reacting a divalent metal compound with a trivalent metal oxide powder in a carboxylic acid-free, aqueous solution or suspension to form an intermediate. This intermediate is then contacted with an anion source such as carbon dioxide; a carbonate-containing compound; an acid or an ammonium salt to form a layered double hydroxide having the formula: A.sub.1-x B.sub.x (OH).sub.2 C.sub.z.mH.sub.2 O, where A represents a divalent metal cation, B represents a trivalent metal cation, C represents a mono- to polyvalent anion, and x, z and m satisfy the following conditions: 0.09 m>0.5. Said layered double hydroxide is typically separated from the suspension by filtering, centrifugation, vacuum dehydration or other known means.
摘要:
There is provided a method for making a divalent or polyvalent organic anion-intercalated hydrotalcite-like materials by first reacting a magnesium-containing powder and a transition alumina powder in an aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a dicarboxylate or polycarboxylate anion to form a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include an oxalate-, succinate- or terephthalate-intercalated hydrotalcite-like material.
摘要:
a process for the production of high-purity urea-ammonium polyphosphate fertilizers from crystalline urea orthophosphate derived from the reaction of wet-process acid and urea. Initially, urea phosphate was pyrolyzed in one stage to give molten urea-ammonium polyphosphates that contained up to 95 percent of the phosphate as polyphosphate, dependent upon the reaction conditions used. Heat to effect condensation of orthophosphate with urea to form polyphosphate was provided by steam. Reaction conditions ranging from a retention time of 1 minute at 350.degree. F to 30 minutes at 260.degree. F were satisfactory. The pyrolyzate contained mixtures of urea, ammonium orthophosphate, and ammonium polyphosphates and was dissolved in aqua ammonia to yield clear liquid fertilizers containing 12 to 15 percent nitrogen and 18 to 29 percent P.sub.2 O.sub.5. Addition of either urea to the process to maintain a urea:biuret ratio of at least 16, or about 2 pounds NH.sub.3 per unit P.sub.2 O.sub.5 to the pyrolysis reactor prevented biuret precipitation in the liquid fertilizers. Granulation of urea-ammonium polyphosphate melt by conventional means gave solids containing 19 to 21 percent N and 45 to 47 percent P.sub.2 O.sub.5. Supplementary, secondary, or micronutrient-containing materials may be incorporated in the liquid or solid products.