Granulation of finely crystalline ammonium sulphate using calcium oxide and sulphuric acid

1992 ◽  
Vol 31 (1) ◽  
pp. 85-93 ◽  
Author(s):  
P. Loganathan ◽  
M. J. Hedley ◽  
S. A. Clark ◽  
N. S. Bolan
1977 ◽  
Vol 15 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Andrew C. Coulson

An underdeveloped country wishing to establish a fertiliser industry ought surely to begin by examining the locally available raw materials. In Tanzania, for example, a report in 1961 drew attention to an anhydrite deposit at Kilwa which could have been used to produce cement, gypsum, and sulphuric acid.2 The latter if combined with ammonia from the oil refinery would have given ammonium sulphate, the fertiliser most commonly used in Tanzania. The report also noted three deposits from which phosphatic fertiliser could have been made. However, the development of these local resources was rejected on the ground that for plants of an efficient size the local market would not be able to absorb all the fertilisers.


1991 ◽  
Vol 161 (1) ◽  
pp. 201-215 ◽  
Author(s):  
D. G. McDONALD ◽  
V. CAVDEK ◽  
L. CALVERT ◽  
C. L. MLLLIGAN

Blood acid-base status and net transfers of acidic equivalents to the external environment were studied in hagfish, Myxine glutinosa, infused with ammonium sulphate (4mequivkg−1 NH4+) or with sulphuric acid (3mequiv kg−1 H+). Hagfish extracellular fluids (ECF) play a greater role in acid-base regulation than in teleosts. This is because hagfish have a much larger blood volume relative to teleosts, despite a relatively low blood buffering capacity. Consequently, infusion of ammonium sulphate produced only half of the acidosis produced in marine teleosts in comparable studies, and hagfish readily tolerated a threefold greater direct H+ load. Furthermore, the H+ load was largely retained and buffered in the extracellular space. Despite smaller acid-base disturbances, rates of net H+ excretion to the external environment were, nonetheless, comparable to those of marine teleosts, and net acid excretion persisted until blood acid-base disturbances were corrected. We conclude that the gills of the hagfish are at least as competent for acid-base regulation as those of marine teleosts. The nature of the H+ excretion mechanism is discussed.


1953 ◽  
Vol 31 (12) ◽  
pp. 1203-1210 ◽  
Author(s):  
R. W. Hummel ◽  
A. B. Van Cleave ◽  
J. W. T. Spinks

Ceric ions, from ceric ammonium sulphate dissolved in aerated 0.8 N sulphuric acid solution, are reduced by Co60 γ-rays and betatron X-rays of 23 Mev. peak energy. G values were calculated on the basis of calculated electron distributions.


2013 ◽  
Vol 13 (9) ◽  
pp. 24087-24125
Author(s):  
L. Škrabalová ◽  
D. Brus ◽  
T. Anttila ◽  
V. Ždímal ◽  
H. Lihavainen

Abstract. New particle formation, which greatly influences the number concentrations and size distributions of an atmospheric aerosol, is often followed by a rapid growth of freshly formed particles. The initial growth of a newly formed aerosol is the crucial process determining the fraction of nucleated particles growing into cloud condensation nuclei sizes, which have a significant influence on climate. In this study, we report the laboratory observations of the growth of nanoparticles produced by nucleation of H2SO4 and water in a laminar flow tube at temperatures of 283, 293 and 303 K, under dry (a relative humidity of 1%) and wet conditions (relative humidity of 30%) and residence times of 30, 45, 60 and 90 s. The initial H2SO4 concentration spans the range from 2 × 108 to 1.4 × 1010 molecule cm−3 and the calculated wall losses of H2SO4 were assumed to be diffusion limited. The detected particle number concentrations, measured by the Ultrafine Condensation Particle Counter (UCPC) and Differential Mobility Particle Sizer (DMPS), were found to depend strongly on the residence time. Hygroscopic particle growth, presented by growth factors, was found to be in good agreement with the previously reported studies. The experimental growth rates ranged from 20 nm h−1 to 890 nm h−1 at RH 1% and from 7 nm h−1 to 980 nm h−1 at RH 30% and were found to increase significantly with the increasing concentration of H2SO4. Increases in the nucleation temperature had a slight enhancing effect on the growth rates under dry conditions. The influence of relative humidity on growth was not consistent – at lower H2SO4 concentrations, the growth rates were higher under dry conditions while at H2SO4 concentrations greater than 1×109molecule cm−3 the growth rates were higher under wet conditions. The growth rates show only a weak dependence on the residence time. The experimental observations were compared with predictions made using a numerical model, which investigates the growth of particles with three different extents of neutralization by the ammonia NH3: (1) pure H2SO4 – H2O particles (2) particles formed by ammonium bisulphate, (NH4)HSO4 (3) particles formed by ammonium sulphate, (NH4)2SO4. The highest growth rates were found for ammonium sulphate particles. Since the model accounting for the initial H2SO4 concentration predicted the experimental growth rates correctly, our results suggest that the commonly presumed diffusional wall losses of H2SO4 are not so significant. We therefore assume that there are not only losses of H2SO4 on the wall but also a flux of H2SO4 molecules from the wall into the flow tube, the effect being more profound under dry conditions and at higher temperatures of the tube wall. Based on a comparison with the atmospheric observations, our results indicate that sulphuric acid alone can not explain the growth rates of particles formed in the atmosphere.


1957 ◽  
Vol 48 (3) ◽  
pp. 326-335 ◽  
Author(s):  
G. A. Salt

A field experiment to test effects of cultural treatments on eyespot (Cercosporella herpotrichoides Fron.), lodging and yield of winter wheat, begun in 1952 (Salt, 1955), was continued on the same site in 1953. In 1952 only eyespot and lodging were severe, but in 1953 take-all (Ophiobolus graminis Sacc.) and weeds were severe also.Squareheads Master 13/4 and Cappelle, each sown at 1½ and 3 bushels/acre, were top-dressed at four different dates with ammonium sulphate at 0, 2 and 4 cwt./acre. Sulphuric acid (12½% b.o.v. at 100 gal./ acre) was sprayed on four of the eight blocks of ten plots in March to control eyespot.Halving the seed rate decreased the percentage of severe eyespot from 63 to 52%, decreased the area stunted by take-all from 36 to 14% and increased yield by amounts ranging from 8·3 cwt. in nitrogendeficient plots to 2·6 cwt./acre in plots well supplied with ammonium sulphate. The fertilizer applied to Squareheads Master at 0, 2 and 4 cwt./acre had little effect on the incidence of eyespot lesions at harvest, but increased the area lodged from 23 to 53 and 60% respectively; it decreased the area stunted by takeall from 47 to 19 and 10% respectively, and increased yield from 13 to 17 and 18 cwt./acre. Cappelle did not lodge and the fertilizer decreased take-all patches from 51 to 28 and 18% respectively, and increased grain from 15 to 20 and 21 cwt./acre. The time when nitrogen was applied to either variety had no important effect on disease incidence or yield.Sulphuric acid sprayed in 1953 on blocks unsprayed in 1952 and so having a higher initial infection of eyespot and weeds, decreased the area lodged and the area covered by weeds, but did not decrease the percentage of straws with eyespot below that in unsprayed plots.


2014 ◽  
Vol 14 (12) ◽  
pp. 6461-6475 ◽  
Author(s):  
L. Skrabalova ◽  
D. Brus ◽  
T. Anttila ◽  
V. Zdimal ◽  
H. Lihavainen

Abstract. New particle formation, which greatly influences the number concentrations and size distributions of an atmospheric aerosol, is often followed by a rapid growth of freshly formed particles. The initial growth of newly formed aerosol is the crucial process determining the fraction of nucleated particles growing to cloud condensation nuclei sizes, which have a significant influence on climate. In this study, we report the laboratory observations of the growth of nanoparticles produced by nucleation of H2SO4 and water in a laminar flow tube at temperatures of 283, 293 and 303 K, under dry (a relative humidity of 1%) and wet conditions (relative humidity of 30%) and residence times of 30, 45, 60 and 90 s. The initial H2SO4 concentration spans the range from 2 × 108 to 1.4 × 1010 molecule cm−3 and the calculated wall losses of H2SO4 were assumed to be diffusion limited. The detected particle number concentrations, measured by the Ultrafine Condensation Particle Counter (UCPC) and Differential Mobility Particle Sizer (DMPS), were found to depend strongly on the residence time. Hygroscopic particle growth, presented by growth factors, was found to be in good agreement with the previously reported studies. The experimental growth rates ranged from 20 nm h−1 to 890 nm h−1 at relative humidity (RH) 1% and from 7 nm h−1 to 980 nm h−1 at RH 30% and were found to increase significantly with the increasing concentration of H2SO4. Increases in the nucleation temperature had a slight enhancing effect on the growth rates under dry conditions. The influence of relative humidity on growth was not consistent – at lower H2SO4 concentrations, the growth rates were higher under dry conditions while at H2SO4 concentrations greater than 1 × 1010 molecule cm−3, the growth rates were higher under wet conditions. The growth rates show only a weak dependence on the residence time. The experimental observations were compared with predictions made using a numerical model, which investigates the growth of particles with three different extents of neutralization by ammonia, NH3: (1) pure H2SO4 – H2O particles; (2) particles formed by ammonium bisulphate, (NH4)HSO4; (3) particles formed by ammonium sulphate, (NH4)2SO4. The highest growth rates were found for ammonium sulphate particles. Since the model accounting for the initial H2SO4 concentration predicted the experimental growth rates correctly, our results suggest that the commonly presumed diffusional wall losses of H2SO4 in case of long-lasting experiments are not so significant. We therefore assume that there are not only losses of H2SO4 on the wall, but also a flux of H2SO4 molecules from the wall into the flow tube, the effect being more profound under dry conditions and at higher temperatures of the tube wall. Based on a comparison with the atmospheric observations, our results indicate that sulphuric acid alone cannot explain the growth rates of particles formed in the atmosphere.


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