No CrossRef data available.
Article contents
The citric solubility of mineral phosphates
Published online by Cambridge University Press: 27 March 2009
Extract
The Fertilisers and Feeding Stuffs Act 1906, Section 10, defines the expressions “soluble” and “insoluble” to mean that the fertilising constituent is soluble or insoluble in water, or, if specified in the invoice, to mean that the fertilising constituent is soluble to the extent guaranteed in a solution of citric acid, or other solvent, of the prescribed strength. In particular the section defines the percentage of soluble phosphate and the percentage of insoluble phosphate to mean respectively the percentage of tribasic phosphate of lime equivalent which, has been, or that which has not been, rendered soluble. “Citric solubility” under the Act is further and more definitely defined in the Fertilisers and Feeding Stuffs General Regulations 1906 as follows:
“When, in an invoice relating to basic slag or basic superphosphate, it is specified that a certain percentage of the phosphate contained in the basic slag or superphosphate is soluble in citric acid, this shall be taken to mean that it is capable of being dissolved to the extent of such percentage when 5 grams of the fertiliser and 500 cubic centimetres of water, containing 10 grams of citric acid, are continuously agitated in a flask or bottle of about 1 litre capacity for the period of half an hour at the ordinary temperature.”
- Type
- Research Article
- Information
- Copyright
- Copyright © Cambridge University Press 1922
References
page 125 note 1 The seller need not, unless he chooses to do so, give any guarantee of citric solubility.
page 126 note 1 Trans. Faraday Soc. 16, Part 2.Google Scholar
page 126 note 2 Soc. Chem. Ind. No. 4, 35.Google Scholar
page 126 note 3 Journ. of Agric. Sci. 1906, Part 4.Google Scholar
page 126 note 4 Ibid. June, 1917.
page 126 note 6 Ibid. Sept. 1916.
page 128 note 1 The writer has to acknowledge his indebtedness to Mr John E. Ritchie, M.A., B.Sc, A.I.C., who has performed the necessary analytical determinations in the experiments on mineral phosphates, and has also given valuable assistance in preparing the memoir. He has also to thank Mr W. T. H. Williamson, B.Sc, A.I.C., for the determinations in the case of dicalcium phosphate.
page 130 note 1 Trans. Chem. Soc. 1917, 111.Google Scholar
page 130 note 2 The values of u from the equation u4/(w – 3u)3 show greater divergences from observational values than the values obtained from either of the equations given in the text. The ratio 
varies from ·72 to ·80, showing that the original concentration is nearly proportional to concentration at the end of 30 minutes shaking. Whatever the reason, the formula u4/w3 gives by far the best fit to the results.
page 132 note 1 Robertson, , J.S.C.I., 35, p. 218.Google Scholar
page 134 note 1 Journ. Agri. Sci. 1909.Google Scholar
page 134 note 2 Ibid. 8, p. 277.