Abstract: A stable ammonium polyphosphate liquid fertilizer is prepared from concentrated wet-process phosphoric acid of 54-62% P.sub.2 O.sub.5, which prior to concentration is treated with a cation exchange resin to remove magnesium and calcium without appreciable reduction of iron and aluminum. The liquid fertilizer will remain substantially sludge-free when stored at 25.degree. C. for six months without the addition of any sequestering or suspending agent.

Abstract: This invention relates to the regeneration of cation exchanger resin containing adsorbed magnesium ions, and the recovery of the magnesium as a crystalline precipitate. The regeneration uses moderate to high concentration aqueous H.sub.2 SO.sub.4, and the recovered precipitate comprises one or more co-crystallization compounds of MgSO.sub.4 and H.sub.2 SO.sub.4.

Abstract: Adjustably metered transfer of resin increments in folded bed ion exchange systems are provided by a method and apparatus in which compacted liquid-containing resin granules are expelled from a column into a metering chamber which is filled to a level of a granule-retaining screen, the cut-off of the granule filling being signaled by liquid moving through the screen to a control level thereabove and/or by an increase in the hydraulic pressure of the liquid below the screen. In preferred embodiments the measuring chamber is provided with a flexible wall which is positioned to either increase or decrease the volume of the measuring chamber and thereby selectively vary the volume of the granule increment captivated by the chamber. The invention provides for the pulsing of resin increments of precisely and adjustably metered volume, and provides a means for keeping the loading and regeneration sides of the system in resin transfer balance.

Abstract: Apparatus and operating method improvements are provided for an ion exchange apparatus system utilizing moving folded beds for loading and regeneration of the resin. The improvements include separate treatment and pulse chambers in the resin circuit from the loading column to the regeneration column, and in the return circuit from the regeneration column to the loading column. With the improved apparatus and method, the resin is transferred in compacted metered increments from and into the loading and regeneration columns.

Abstract: Adsorbed calcium is selectively removed from cation exchange resins in the presence of adsorbed magnesium by eluting the resin with aqueous sulfuric acid saturated with CaSO.sub.4 and undersaturated with MgSO.sub.4 to obtain a solution supersaturated with CaSO.sub.4 from which the CaSO.sub.4 can be readily precipitated. The magnesium is subsequently removed from the resin by eluting with aqueous sulfuric acid, such as 20-70% H.sub.2 SO.sub.4. The method is advantageously used in the regeneration of cation exchange resins, such as the loaded resins used for treatment of phosphate rock-derived phosphoric acid.

Abstract: A method and apparatus is provided for removing large volumes of contaminants or for recovering valuable minerals present in trace amounts or greater quantities by ion exchange treatment of phosphoric acid liquids or the like as they flow through a resin bed wherein ions in the liquid are sorbed into the resin by an ion exchange mechanism. The resin bed is folded, moving bed which exhibits all of the advantages of a packed ion exchange resin bed. Laminar flows are developed at times in the moving bed system, while the moving bed used is of a "folded" type having a maximum height approximately one-third that of conventional, unfolded countercurrent units. The ion exchange treatment occurs within a loading vessel resin bed, the beads in the feed portion of which become exhausted and sequentially move out of the loading vessel for subsequent regeneration and rinsing, followed by eventual return to the loading vessel.

Abstract: A method and apparatus is provided for removing contaminants or for recovering valuable minerals in trace amounts by ion exchange treatment of liquids such as municipal and industrial waste waters, ore mining and processing tailings, and the like as they flow through a resin bed wherein ions in the liquid are sorbed into the resin by an ion exchange mechanism. The resin bed is a folded, moving bed which exhibits all of the advantages of a packed ion exchange resin bed. Laminar flows are developed throughout the moving bed system to maintain all interfaces intact, even during the rinsing operation, while the moving bed used is of a "folded" type having a maximum height approximately one-third that of conventional countercurrent units. The ion exchange treatment occurs within a loading vessel resin bed, the beads in the feed portion of which become exhausted and sequentially move out of the loading vessel for subsequent regeneration and rinsing, followed by eventual return to the loading vessel.

Abstract: A method and apparatus is provided for removing large volumes of contaminants or for recovering valuable minerals present in trace amounts or greater quantities by ion exchange treatment of phosphoric acid liquids or the like as they flow through a resin bed wherein ions in the liquid are sorbed into the resin by an ion exchange mechanism. The resin bed is folded, moving bed which exhibits all of the advantages of a packed ion exchange resin bed. Laminar flows are developed at times in the moving bed system, while the moving bed used is of a "folded" type having a maximum height approximately one-third that of conventional, unfolded countercurrent units. The ion exchange treatment occurs within a loading vessel resin bed, the beads in the feed portion of which become exhausted and sequentially move out of the loading vessel for subsequent regeneration and rinsing, followed by eventual return to the loading vessel.