Sulphur fertilisers

Vallejo F, Tomas-Barberan FA, Garcia-Viguera C. 2003. Effect of climatic and sulphur fertilisation conditions, on phenolic compounds and vitamin C, in the inflorescences of eight broccoli cultivars. Eur Food Res Technol 216 395-401. 

Wieser, H., Gutser, R., von Tucher, S. 2004. Influence of sulphur fertilisation on quantities and proportions of gluten protein types in wheat flour. J Cereal Sci 40 239-244. 

Factors influencing the availability of sulphur fertilisers to alfalfa and corn. Soil Science Society America Proceedings, 28, 406-408. 

Industrially. phosphoric(V) acid is manufactured by two processes. In one process phosphorus is burned in air and the phos-phorus(V) oxide produced is dissolved in water. It is also manufactured by the action of dilute sulphuric acid on bone-ash or phosphorite, i.e. calcium tetraoxophosphate(V). Ca3(P04)2 the insoluble calcium sulphate is filtered off and the remaining solution concentrated. In this reaction, the calcium phosphate may be treated to convert it to the more soluble dihydrogenphosphatc. CafHjPOjj. When mixed with the calcium sulphate this is used as a fertiliser under the name "superphosphate . 

In nitrogenous fertiliser solutions of the NH4NOJ—NHj —HjO type corrosion of steel can be prevented by 500 p.p.m. of sulphur-containing inhibitors, e.g. mercaptobenzothiazole, thiourea and ammonium thiocyanate. However, these inhibitors are not so effective where most of the NHj is replaced by urea. For these solutions phosphate inhibitors such as (NH4>2HP04 and polyphosphates were more effective... 

Sulphuric acid is an important industrial chemical. It has been said that the output of sulphuric acid is a measure of the wealth of a country, as it is used in the manufacture of fertilisers, detergents, pigments and fibres, amongst many other products. In the first stage of the process, sulphur is burned to produce sulphur dioxide. 

Sulphuric acid is used to manufacture other nitrogen-containing fertilisers such as ammonium sulphate, (NH4)2S04. Phosphorus-containing fertilisers, derived from rock phosphates such as Ca3(P04)2, are also manufactured using sulphuric acid. 

Plant nutrients are interesting not only in connection with the yields and the fertilisation, but also with regard to environmental effects of energy conversion processes. Thus, they are regulated in various standards. Nitrogen (N), phosphorous (P) and potassium (K), as well as sulphur (S) and chlorine (Cl) are the most important environmentally relevant macronutrient and micronutrient elements. 

The element has a definite fertilising action 2 which is exerted in two ways (1) It supplies sulphuric acid by bacterial oxidation, the presence of the acid increasing the availability of certain mineral constituents in the soil, such as alkalis, ferric oxide, alumina and phosphates. (2) It facilitates the work of the ammonia and nitrifying bacteria, thus placing larger supplies of nitrogen at the disposal of the plants. But although such action may be beneficial in some soils it is equally harmful in others, and sulphur should not be applied to a soil already acid.3... 

Several methods of carbon dioxide production are in commercial use. These include the reaction between sulphuric acid and sodium bicarbonate, the combustion of fuel oil, the extraction of carbon dioxide from the flue gas of a boiler or similar heating facility, the distillation of alcohol and the fermentation of beer carbon dioxide is also a byproduct of fertiliser manufacture. Following manufacture the gas must be cleaned to ensure it is free from impurities and is fit for purpose. Two typical processes are described below. 

Determination of the Nitrogen.—The Kjeldahl-Ulsch method is used, about 2 grams of the flour being treated with 20 c.c. of the phosphoric-sulphuric acid mixture see Fertilisers, Vol. I, p. 122) N x 6-25 — nitrogenous substances in general or proteins. 

To determine the alkalies, another 200 c.c. of the liquid are evaporated to dryness, the residue being gently calcined and taken up in water and hydrochloric acid, and the non-alkali metals eliminated by means of ammonia and ammonium carbonate.1 The filtrate is evaporated to dryness with a little sulphuric acid and the residue heated to expel the ammonium salts and then weighed this gives the sodium and potassium sulphates together. If required, the two metals may be determined separately (see Fertilisers, Vol. I, pp. 124 and 135). 

Ammonium in aerosols originates from the neutralisation of sulphuric and nitric acid by ammonia. Ammonia is emitted by different sources, most notably animal manure, traffic and application of fertiliser. In general, emissions are for the largest part (80-95%) associated with agricultural activities [19]. Erisman et al. [20] estimated the natural emissions at about 10% of the total emissions in Europe. This percentage includes contributions from wild animals and wetlands. We assume a similar percentage for ammonium in north-western Europe. 

In another process crude calcium acid phosphate is mixed with ammonium sulphate solution below 80° C., and the mixture concentrated and filtered, when (NH4)H2P04 crystallises. (NH4)2HP04 is made from ammonia, fumes of phosphoric acid and water.3 Or calcium phosphate is just dissolved in sulphuric acid, the calcium sulphate filtered off and the add solution treated with ammonia and carbon dioxide. The ammonium sulphate and phosphate form a good mixed fertiliser.4... 

Phosphorus (0.11% of the lithosphere) is found mainly in minerals based on calcium phosphate, collophanite, the monohydrate, Ca3(P04)2.H20, and apatite, CagF(P04)3. About 90% of the phosphate rock mined is converted into fertilisers, the rest is used for making elementary phosphorus, phosphorus compounds and such alloys as phosphor bronze. For fertilisers rock phosphate is finely ground and treated with sufficient concentrated sulphuric acid to convert it to the soluble dihydrogen phosphate ... 

Inorganic Chemicals Ammonia, Sulphuric Acid, Fertilisers... 

Law CS, Watson AJ, Liddicoat MI, and Stanton T (1998) Sulphur hexaflouride as a tracer of biogeochemical and physical processes in an open-ocean iron fertilisation experiment. Deep-Sea Research II 45 977-994. 

The key bulk chemicals are the inorganic acids (sulphuric, nitric and hydrochloric), phosphates and fertilisers, chlorine, caustic soda and soda ash. and the organic intermediate materials for petrochemicals (olefins, methanol and aromatic compounds), as w ell, of course, as the petrochemicals themselves, especially the ever-incieasing range of thermoplastic polymers. 

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