Effects of sulphur

Free-cutting or free-machining grades of steel normally contain up to 0.2% of sulphur, although up to 0.5% is possible. Other elements such as lead and selenium may also be present. In these cases special precautions are necessary and are outlined in Chapter 4. 

Low sulphur contents, e.g. 0.015%, have been shown to increase the risk of hydrogen cracking in one specific instance when a C-Mn steel was being welded in a situation where a hardened HAZ was likely. 

Although the emphasis in recent years has been on the role of low sulphur contents in promoting hydrogen cracking, it is also possible for a sulphur content which is relatively high to give liquation cracks in the HAZ and for these minute cracks or hot tears to act as potent nuclei for the nucleation of hydrogen cracks. Steels 

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Nitration in organic solvents is strongly catalysed by small concentrations of strong acids typically a concentration of io mol 1 of sulphuric acid doubles the rate of reaction. Reaction under zeroth-order conditions is accelerated without disturbing the kinetic form, even under the influence of very strong catalysis. The effect of sulphuric acid on the nitration of benzene in nitromethane is tabulated in table 3.3. The catalysis is linear in the concentration of sulphuric acid. 

Unlike the effect of sulphuric acid upon nitration in nitric acid ( 2.2.3 where zeroth-order reactions are unknown), the form of the catalysis of zeroth-order nitration in nitromethane by added sulphuric acid does not deviate from a first-order dependence with low concentrations of catalyst. ... 

Table 5.3 Typical effects of sulphur dioxide concentrations in air...

Janik-Czachor, M., Szummer, A. and Szklarska-Smialowska, Z., Effect of Sulphur and Manganese on Nucleation of Corrosion Pits in Iron , Br. Corr. J., 7, 90 (1972)... 

The effect of sulphur from the gas phase is critically dependent on the effectiveness of fuel combustion. With good combustion to the limit of the available oxygen, and even down to 50% air deficiency, no serious effect was found from high-sulphur fuel in tests with 321S12 steel up to the usual limit of service temperature at 850°C, as shown in Table 7.9. With 310S24 steel at 1 100°C some effect from high sulphur content was found in 2 1 air gas with effective combustion, but none in 4 1 and 6 1 mixtures. 

The behaviour of nickel is very dependent upon the type of sulphidising gas that is used, and the effects of sulphur vapour, hydrogen sulphide. 

A limited degree of control over the corrosivity of the product packed is possible. Minor pH adjustments may be helpful, especially in ensuring an anodic relation of tin to steel corrosion promoters, like nitrate, sulphur and copper may be excluded from necessary additives, such as water and sugar, and from sprays applied to crops approaching harvest. The effect of sulphur compounds which may remain from spray residues is complex but often includes reversal of the tin-iron polarity. 

Fig. IS.S Effect of sulphuric acid concentration on chromate passivation of zinc. Solution 182g/1 of Na2Cr207 -2H20 + H2SO4 as indicated temp. I8°C I 0 x 10 mg Zn/cm =...

E. Lamy-Pitara, L. Bencharif, and J. Barbier, Effect of sulphur on the properties of platinum catalysts as characterized by cyclic voltammetry, Appl. Catal. 18, 117-131 (1985). 

Y. Matsumoto, T. Onishi, and K. Tamam, Effects of Sulphur on a Palladium Surface on the Adsorption of Carbon Monoxide and the Adsorption and decomposition of nitric oxide, J.C.S. Faraday I 76, 1116-1121 (1980). 

Burch, R. and Watling, T.C. (1998) The effect of sulphur on the reduction of NO by C3H6 and C3H8 over Pt/Al203 under lean-burn conditions, Appl. Catal. B 17, 131. 

The effect of sulphuric acid and oleum on the explosive properties of nitromethane, dinitrotoluene, trinitrobenzene and trinitrotoluene was studied. They are considerably sensitised. 

Figure 9.3 shows the gas chromatogram obtained for a sulphur containing sediment sample before and after treatment with tetrabutylammonium sulphate-sodium sulphate. It is seen that the effects of sulphur and sulphur containing organic compounds in the sample are completely eliminated by this treatment. 

The effect of sulphuric acid, a likely impurity from the usual preparation, in increasing sensitivity to detonation and decomposition has been studied [6],... 

Kumar, 0. and Vijayaraghavan, R. Effect of sulphur mustard inhalation exposure on some urinary variables in mice, J. Ppl. Toxicol, 18(4) 257-259, 1998. 

Picinelli, A., Bakker, J., and Bridle, P., Modell wine solutions effect of sulphur dioxide on colour and composition during ageing, Vitis, 33, 31, 1994. 

Bakker, J. et al.. Effect of sulphur dioxide and must extraction on colour, phenolic composition and sensory quality of red table wine, J. Sci. Food Agric., 78, 297, 1998. 

Savage, J.R.K. and Woods, A.C. Differential effects of sulphur mustard on S-phase cells of primary fibroblast cultures from Syrian hamsters. Mutat. Res. 84 375-387, 1981. 

This work will greatly enhance the reliability and effectiveness of sulphur fertilization and greatly improve the efficiency of agricultural food production. In light of present and forecasted world food needs, this will be a significant accomplishment. ... 

X-Ray crystal structure data on [Co(ete)(N02)Cl]Cl (ete = l,9-diamino-3,7-dithianonane) indicates the complex to have the uns-cis structure with the nitro-group trans to the nitrogen and the chlorine trans to the sulphur, showing that in its formation from u-cis[Co(ete)(N02)2]+ the greater trans effect of sulphur allows the trrws-nitro-group to be replaced.403... 

I.O. Skalpe, Long-term effects of sulphur dioxide exposure in pulp mill. Brit. J. Ind. Med. 21 69, 1964. 

Figure 2 Effect of sulphur on the relative activity profile of a fixed bed reactor catalyst (1000 time units) (x activity. relative mass sulphur...

The effect of sulphur on the activity profile is shown in Figure 2. The sulphur poisoning arises from sulphur impurities found in the synthesis gas, which is derived from coal. Sulphur is a common F-T catalyst poison [2,11] and it is apparent from the results that the top portion of the reactor is acting as a guard bed" to remove this impurity. The finding that sulphur is only found to be present in the top section of the catalyst bed has been observed previously for F-T and related catalysts [12-15]. 

Sulphur-poisoning studies of nickel catalysts have been performed with fixed-bed tube reactors at 800 - 950 °C under 1 - 20 bar total pressure with real and simulated gasification gas mixtures containing H2S (50 - 1000 ppmv). The effect of sulphur concentration of the gas and the operation conditions will be presented and discussed in this paper. 

The cast iron muffle was replaced by a fireclay brick muffle. The arch was made of carborundum which conducted heat well and withstood the effect of sulphuric acid. The outer brickwork was circular in shape and not rectangular as in the Mannheim furnace. Consequently, the surface area of the muffle was smaller so that the loss of heat due to radiation was reduced to a minimum. The interchangeable blades on the four arms of the stirring device, which revolved at a velocity of 1 to 2 r. p. m., were made of carborundum which resists to wear and does not pollute the product either with iron or chromium. This is of great importance when manufacturing sulphate for glass works. 

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