Calcium Metaphosphate Chemical composition and Properties - Fertilizers

Abstract

The composition, solubility, and hygroscopicity of the solids, the stability of their solutions, and their tendencies to undergo hydrolysis, as influenced by the CaOuPsOs ratio and by silica content, were considered for both air-cooled and quenched materials.The comparative tendencies of P03 and PO4 to undergo fixation by the soil were also recorded. The determined values are considered to be useful as pilot information in the handling of the melts, in the requisite technic for the chemical analysis and evaluation of the final products, and for guidance in the planning of supplemental Neubauer, pot, and agronomic studies.Composition and Solubility of Semi-com-mercial Calcium MetaphosphatesThe compositions of four of the products studied are indicated by the detailed analyses of Table I. Product 443-A, of high silica content, was the most acidic and most soluble of all the air-cooled products of this and subsequent tables. The data show that the products are essentially calcium metaphosphates and that all products contained P08 in excess of the CaO:P2Os ratio that would be accounted for by the respective CaO contents.The solubility results of Table II were obtained from agitated extractions of 5-gram charges of 100-mesh products per liter of solvent for periods of 1, 20, 24, and 48 hours at room temperature. Only limited hydrolysis was induced by the acid content of the precipitant solution. The marked

DNA Profile Analysis and Interpretation

“…The K d-ap for ortho-was 57% less than the higher-chain polyphosphate species, K d-ap = 0.29. Comparable results demonstrating greater sorption of pyrophosphate and tripolyphosphate, relative to orthophosphate, have been previously observed through the results of static sorption tests (Blanchar and Hossner 1969b;a;c;MacIntire et al 1937;Scott 1958).…”

Potassium Fixation, Differential Fixation of Potassium from Incorporations of Metaphosphate and Sulfate in Two Soils

“…Through successive aqueous and ammonium acetate extractions, they obtained complete recoveries of additive potassium from 10-gram charges of a red clay subsoil that contained 100-and 500-mg. inputs of K20 as potassium sulfate. But the same analytical technique registered only "the ability of the soils of the water regions to retain applied potassium against the leaching action of water" (7), and concluded that no fixation of potassium resulted from surface applications of the sulfate and a metaphosphate fertilizer (7, p. 3, 25) at the rate of 1250 pounds of K20 per acre surface. Volk (23) and Shaw and Maclntire ( 22) also reported that potassium fixation did not occur in soils that were kept moist.…”

“…e Initial pH 5.0. d Initial pH 5.6. Potassium contents of the eight annual rain-water drainages had been determined by means of the platinum-iodide colorimetric procedure (2, 27). The "replaceable" potassium contents shown in Tables III and VI were obtained through overnight extractions of ammonium acetate (pH 7) and subsequent leachings from 10-gram charges of 1-mm. air-dried soils.…”

“…Fullerton Silt Loam p2o6 In finding that "leaching removed all of the 1250-pound (K20) applications of potassium per acre from the surface foot of the KC1-and KaSOi-treated soils" Ayres and Hagihara (7) analyzed leachates from successive increments of 2.5 inches of water to totals of 90 to 100 inches. Apparently, they did not allow the soil columns to become dry between percolations, a condition the present authors have found conducive to retention and fixation of potassium from additions in solution.…”

Crop Response to Calcium Metaphosphate on Alkaline Soils1

“…It has been pointed out by several workers (2, 6, 13) that the solution of calcium metaphosphate and its subsequent conversion to the ortho form, in aqueous media at least, are influenced by particle size, temperature, acidity, time of contact with the medium, and chemical ~nd physical properties of the material. However, very little 1s known about the reaction of calcium metaphosphate with the soil, _though several workers (3,6,7) have reported that fixatiOn of metaphosphates by the soil exceeds the fixation of orthophosphates. These conclusions were based on findings of .…”