Superphosphate production: The influence of various factors on the speed of reaction and the composition of the product

Abstract

The effects of acid concentration, acidlrock ratio, and fineness of grinding on the interaction between Moroccan phosphate rock and sulphuric acid, in the preparation of superphosphate, have been studied.An organic-solvent technique has been used t o follow the course and the rate of the chemical reactions. This method has been adopted because the precise composition of the superphosphate cannot be found by the analysis of water extracts, since interaction occurs between unchanged phosphate rock and free acids during the extraction.Results are given in the form of Tables and graphs.

Fertilizer Technology, Production of Ordinary Superphosphate for Immediate Use in Ammoniation and Granulation Processes

“…Calculated from chemical analysis of product. 6 Samples washed immediately after 1-hour denning time. e Conversion of P2O5 to citrate-soluble form.…”

“…26.0% free NH3, 55.5% NH4N03, 18.5% H20. 6 S standard potassium chloride; G granular (90% -6 +28 mesh) potassium chloride. 6 Degree of ammoniation of ordinary superphosphate after deducting ammonia required to neutralize excess acid and any acid included in formulation.…”

“…Noller, Ward, and Huffman (71) have observed similar results with young calves. However, the gain and feed efficiency of young pigs fed soybean protein basal diets were improved by either the addition of proteolytic enzymes to the diet (6) or by partial prehydrolysis of soybean protein with enzymes (5).…”

“…This suggested the possibility of an integrated process in which ordinary superphosphate could be produced continuously and used, immediately after denning, in the continuous ammoniator process for the production of granular highanalysis fertilizers. Studies of the variables mentioned were also reported by Nunn and Dee (6). However, their investigation did not extend to the determination of conditions for producing superphosphate having a high degree of phosphorus pentoxide conversion and physical properties suitable for ammoniation immediately after denning.…”

The fate of fertiliser P in soil under pasture and uptake by subterraneum clover – a field study using 33P-labelled single superphosphate

“…single superphosphate), which was then denned and made into granules using a granulating drum. However, some of the issues with this procedure are: 1) it is complex and time consuming (Hedley et al 1988;Nunn and Dee 1954); 2) incomplete acidulation of the rock phosphate can occur (Bolan et al 1987;Nunn and Dee 1954); 3) as a by-product of the acidulation process a cocktail of fluorosilicic and hydrofluoric acid vapour is emitted (Leikam and Achorn 2005); 4) the source of phosphate rock can affect the chemical composition and solubility of the SSP (Braithwaite et al 1992;Hedley et al 1988); and 5) there can be a large variation in granule size and weight within each batch of fertiliser made (Braithwaite et al 1992;Fogel 1960). The relatively large amount of rock phosphate required for this procedure, and the low recovery of granules with a consistent size and weight needed for experimentation purposes, can cause a considerable dilution of radioactivity in the 'ideal' granules.…”