Abstract: The process allows essentially all of the nitrogen and P.sub.2 O.sub.5 values in the treated black ammonium polyphosphate liquid to be recovered in the form of valuable clarified product. In the process, a heel of black liquid fertilizer is first clarified by a prior-art procedure using flocculants. The improvement over the prior art picks up with the byproduct tops which is then diluted with the water of formulation required to dissolve additional amounts of ammonium polyphosphate melt. This diluted liquid is filtered, the filter cake containing upwards of 99 percent of the undesirable black carbonaceous material is discarded, and the clear filtrate, which contains essentially all of the nitrogen and P.sub.2 O.sub.5 originally in the tops, is then used in lieu of the prior-art water of formulation to dissolve additional ammonium polyphosphate melt to produce more black ammonium polyphosphate liquid.

Abstract: An energy efficient process and apparatus is described that allows production of concentrated polyphosphate containing ammonium phosphate suspension fertilizers that can be stored and handled at temperatures well below 0.degree. F. Ammoniation of the merchant-grade wet-process phosphoric acid provides all of the heat required by the process. Use of a unique enlarged dual pipe-type reactor system allows operation for extended periods without clogging. To obtain the high concentration and excellent low temperature storage and handling properties, the ammonium phosphate must be produced within closely specified and previously undisclosed N:P.sub.2 O.sub.5 and solution concentration ranges. Operation outside the specified composition range will reduce the maximum plant food concentration and may cause some of the ammonium phosphate salts to crystallize and foul the heat-transfer surfaces.

Abstract: Crystalline urea phosphate is pyrolyzed in one stage to give molten urea ammonium polyphosphates that contains up to 95 percent of the phosphate as polyphosphate. These are then processed into high-analysis solid or liquid fertilizers. Addition of urea to the process to maintain a urea:biuret ratio of at least 16 prevents precipitation of biuret in the liquid fertilizers.

Abstract: Particulate carbonaceous matter in ammonium polyphosphate liquid made from impure wet-process phosphoric acid is removed by intimately mixing the liquid with a combination of selected organic flocculating agents and then transferring the mixture to a separation vessel where the particulate carbonaceous matter floats rapidly to the surface. Clarified liquid that contains essentially no particulate carbonaceous matter is withdrawn from the bottom of the separation vessel. The particulate carbonaceous matter and a minor portion of the input ammonium polyphosphate liquid are withdrawn from the top of the separation vessel and processed into fluid or solid fertilizers.

Abstract: 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.

Abstract: The process allows essentially all of the nitrogen and P.sub.2 O.sub.5 values in the treated black ammonium polyphosphate liquid to be recovered in the form of valuable clarified product. In the process, a heel of black liquid fertilizer is first clarified by a prior-art procedure using flocculants. The improvement over the prior art picks up with the byproduct tops which is then diluted with the water of formulation required to dissolve additional amounts of ammonium polyphosphate melt. This diluted liquid is filtered, the filter cake containing upwards of 99 percent of the undesirable black carbonaceous material is discarded, and the clear filtrate, which contains essentially all of the nitrogen and P.sub.2 O.sub.5 originally in the tops, is then used in lieu of the prior-art water of formulation to dissolve additional ammonium polyphosphate melt to produce more black ammonium polyphosphate liquid.

Abstract: An energy efficient process and apparatus is described that consists of a pipe reactor, melt dissolution tank, acid and ammonia heat exchangers, product cooler, and clay addition facilities in which a concentrated polyphosphate containing ammonium phosphate suspension fertilizers is produced that can be stored and handled at temperatures well below 0.degree. F. The suspension is produced from merchant-grade wet-process phosphoric acid which is ammoniated in a unique enlarged pipe-type reactor sized to have throughputs of 20-100 pounds P.sub.2 O.sub.5 /hr-in.sup.2 and 0.25-2 pounds P.sub.2 O.sub.5 /hr-in.sup.3 of internal reactor area and volume, respectively, and which can be operated for extended periods without clogging. All of the heat required by the process is obtained by transferring a portion of the heat of ammoniation from the hot liquid in the melt dissolution tank to the incoming acid and ammonia streams. The resultant product contains 10 to 40 percent polyphosphate and when produced within an N:P.