Abstract:
Phosphate rock and sulfuric acid are reacted under conditions which result in the formation of calcium sulfate hemihydrate and phosphoric acid of about 35% to about 55% P.sub.2 O.sub.5. A two vessel reaction system is used in which the reaction slurry undergoes intra- and inter- vessel circulation (preferably through a draft tube). The solution portion of the slurry in the first vessel (the "dissolver") is preferably maintained at a negative sulfate concentration (i.e. excess Ca.sup.+2) and the solution in the second vessel (the "crystallizer") is preferably maintained at a positive sulfate ion concentration. Also preferred is that the second vessel be maintained at a reduced pressure, (e.g. to provide evaporation cooling). Better filtration rates can thus be obtained due to the favorable shape, dominant size and size distribution of the hemihydrate crystals. Most preferred is that a crystal modifier (e.g. a sulfonic acid, a sulfonic acid salt, tall oil fatty acids or alkoxylated or esterified tall oil fatty acids) be present in the crystallizer. Surprisingly, the sulfuric acid used in the process can be less (e.g., 0.5-10%) than the stoichiometric amount to convert the calcium in the feed phosphate rock to calcium sulphate.
Abstract:
An apparatus for reacting phosphoric acid and ammonia to form a molten reaction mixture, to which water can be added to produce an ammonium polyphosphate product, comprises:(A) fluid reactor means having a plurality of inlet means suitable for administration of reactants and positioned to provide for rapid ammoniation of the phosphoric acid with evolution of heat and aperatures to the other end providing exit means for the reaction mixture, said reactor means being adapted to the expulsion of the reaction mixture by steam generated in situ;(B) means for separating the steam from the liquid product solution and removal of said steam from the apparatus; and(C) columnar vessel means having outlet means at one end and enclosing at the other end the exit means of said fluid reactor means and a plurality of barrier means partially blocking said columnar vessel means in spaced-apart relationship and having aperatures therein for passage of reaction product therethrough and inlet means suitable for introduction of a quenching fluid (e.g., water).
Abstract:
A tamper indicating closure comprising a one-piece molded plastic closure which threads onto the finish of a container such that when the closure is removed from the container, a tamper indicating band becomes separated from a lower end of a cap member of the closure. The tamper indicating band is joined to the closure along a weakened frangible line. The band includes a flexible Y-shaped annular flap segmented into tabs and attached to the lower end of the annular tamper band. When the closure is applied to the container, the annular band folds radially inward and up toward the cap member. The interior surface of the band and the first leg of the annular band include corresponding ratchet teeth which are designed to accommodate a varying degree of finish tolerances and which engage upon removal of the cap from the container. A second leg of the annular flap extends outwardly beneath a peripheral bead on the finish of the container when the closure is fully attached. Upon removal of the closure from the container, the second leg abuts underneath the peripheral bead to create resistance. The ratchet teeth on the band and flap are caused to engage with one another while the first leg wedges between the outside edge of the peripheral bead and the skin of the cap member. Further removal of the closure causes the tamper indicating band to sever from the cap member along the weakened line.
Abstract:
Phosphate rock and sulfuric acid are reacted under conditions which result in the formation calcium sulfate hemihydrate and phosphoric acid of about 30% to about 55% P.sub.2 O.sub.5. A two vessel reaction system is used in which the reaction slurry undergoes inter- and intra- vessel circulation. This results in excellent dispersion of reactants and minimization of temperature and concentration gradients throughout the slurry.
Abstract translation:磷酸盐岩和硫酸在导致形成约30%至约55%的P2 O 5的硫酸钙半水合物和磷酸的条件下反应。 使用反应浆料经受血管内和血管内循环的二血管反应系统。 这导致反应物的优异分散和整个浆料中温度和浓度梯度的最小化。
Abstract:
Aqueous ammonium phosphate solutions can be produced using an apparatus comprising: a fluid reactor having a plurality of inlets at one end thereof suitable for the admission of phosphoric acid, ammonia and water, the inlets being so positioned as to provide for rapid ammoniation of the phosphoric acid with the evolution of heat, to produce a reaction product mixture containing a liquid portion and steam, the fluid reactor having an exit for the expulsion of the reaction products mixture at the other end thereof, by steam generated by the heat liberated in the ammoniation process; a columnar vessel having an outlet at one end and, at the other end, enclosing the exit of the fluid reactor, a plurality of barriers obturating the columnar vessel in a spaced-apart relationship, and having a plurality of apertures therein for the passage of reaction products mixture therethrough; an inlet quench device connected to the columnar vessel for introduction therein of a liquid aqueous quenching fluid; and, a device in communication with the exit of the fluid reactor, for separating steam from the liquid portion of the reaction mixture and removing the separated steam from the apparatus.
Abstract:
The invention comprises a multi-vessel reaction apparatus useful for reacting phosphate rock and sulfuric acid in which the reaction slurry undergoes intra- and inter- vessel circulation (preferably through a draft tube). The solution portion of the slurry in a first vessel or set of vessels (the "dissolver") is preferably maintained at at lower sulfate ion concentration and the solution portion of the slurry in the second vessel or system of vessels (the "crystallizer") is preferably maintained at a positive sulfate ion concentration. Also preferred are means for maintaining the second vessel or set of vessels at a reduced pressure. Most preferred is that means be included in at least one said vessel for incorporating a crystal modifier (e.g. a sulfonic acid, a sulfonic acid salt, tall oil fatty acids or alkoxylated or esterified tall oil fatty acids) in the crystallizer. The system can be used in the anhydrite, hemihydrate or gypsum types of processes.
Abstract:
A system for the preparation of phosphoric acid from phosphate rock and sulfuric acid, includes in combination a first reaction vessel containing a first slurry comprising calcium sulfate hemihydrate, monocalcium phosphate and phosphoric acid, a second reaction vessel containing a second slurry comprising calcium sulfate hemihydrate, circulation means including a draft tube disposed centrally in each of said vessels and an agitator positioned axially in each of said vessels within said draft tube, a first conduit interconnecting said first and second reaction vessels for conducting said first slurry from said first reaction vessel to said second reaction vessel, a second conduit interconnecting said vessels for conducting said second slurry from said second reaction vessel to said first reaction vessel, an inlet pipe for introducing phosphate rock and phosphoric acid to said first reaction vessel, said inlet pipe connected with the interior of said draft tube in said first vessel and wherein a vent is connected to said inlet pipe to permit escape of gases and, thus, increasing the rate of flow of said phosphate rock and phosphoric acid to said first reaction vessel.
Abstract:
Phosphoric acid and ammonia are reacted together with additions of water when necessary in a reaction vessel to form a molten entrained stream reaction mixture to which a water quench is added to produce an ammonium polyphosphate liquid fertilizer.
Abstract:
Phosphoric acid is prepared from phosphate rock and sulfuric acid by using a reaction train comprising a dissolving slurry and a crystallization slurry maintained at different sulfate levels. Both inter and intra vessel circulation are used at high rates to minimize reagent concentration gradients and temperature gradients and provide a suitable crystallization environment. Preferably, the intra vessel circulation is substantially in plug flow, as through a draft tube.