Sulphuric acid Glover

The final products are then sulphuric acid, nitrogen oxide and oxygen the two latter react and the cycle goes on. Theoretically therefore, the nitrous fumes are never used up. In practice, however, some slight replacement is needed and this is achieved by adding a little concentrated nitric acid to the mixture in the Glover tower ... 

Historical.—This process had its origin in the early preparation of sulphuric acid by the oxidation of sulphur dioxide with nitric acid, for which operation lead chambers were first introduced in 1746 by Roebuck of Birmingham. In 1793 Clement and Desormes showed that under proper conditions the nitric acid aids the oxidation, which is in the main effected by atmospheric oxygen, and the injection of steam having already been introduced in 1774 by de la Follie, the basal chemical process was much the same as to-day. Gay-Lussac s tower was first suggested by that chemist in 1827 and was first used in 1835, being introduced into Britain in 1844. J. Glover constructed his first tower at Newcastle in 1861. 

Another purpose served by the Glover tower is that it relieves the lead chambers of the production of part of the acid, and it may account for as much as 16 per cent, or more of the total yield of acid, due to the conversion of sulphur dioxide into sulphuric acid inside the tower indeed, a tower of similar type is sometimes interposed between two of the chambers with a view to the same result.2... 

Theory of the Action in the Gay-Lussac and Glover Towers.— The gases issuing from the chambers consist mainly of nitrogen dioxide, nitric oxide and atmospheric nitrogen. The two former are dissolved by the sulphuric acid in the Gay-Lussac tower with formation of a solution of nitrosylsulphuric acid in excess of sulphuric acid (see also below) ... 

As the formation of nitrosylsulphuric acid is a reversible process, dilution of the sulphuric acid solution in the Glover tower tends to cause hydrolysis, which is aided by the high temperature the oxides of nitrogen resulting from the decomposition pass on with the sulphur dioxide and excess of air to the chambers, whilst the sulphuric acid descends and issues at the bottom of the tower. 

In addition to the foregoing process, however, the Glover tower actually produces sulphuric acid. This is brought about by interaction of the sulphur dioxide in the burner gases with nitrosylsulphuric acid, as follows ... 

An advantage possessed by this series of changes is that it explains more satisfactorily than the preceding theory why much sulphuric acid can be formed in the Glover tower. In the lead chambers the acid formed is so weak that the nitrososulphonic acid stage is possibly absent from the series. 

Extraction.—(1) From Pyrites.—In the oxidation of the pyrites (or other sulphur mineral) for the formation of sulphur dioxide in the manufacture of sulphuric acid, foreign elements like arsenic and selenium also undergo oxidation and pass ofC as vapours with the sulphur dioxide. The selenium dioxide produced in this manner their suffers more or less complete reduction by the sulphur dioxide, when finely divided selenium separates, mainly in the lead chambers, as a red, amorphous powder, accompanied possibly by some of the greyish-black form a portion of the dioxide is also found in the Glover tower acid. The amount of selenium in the chamber mud depends, of course, on the nature of the pyrites relatively large quantities of compounds of arsenic, zinc, tin, lead, iron, copper or mercury are always present, arising almost entirely from impurities in the pyrites. 

The kind of sulphuric acid used varies with the nature of the nitric acid it is desired to produce. For a dilute nitric acid of 1.35-1.4 sp. gr. it is sufficient to use 60° Be. (141° Tw.) sulphuric acid direct from the Glover tower. The first distillate will be strongest, and the last nearly pure water. Should, however, a stronger H.N03 of over 1.5 sp. gr. be required (as is now nearly always the case), a more concentrated 66° B6. (167° Tw.) sulphuric acid must be employed, and the NaN03 is often previously melted. 

A nitric acid of r.35-1.40 sp. gr. is also used for the Glover towers in the manufacture of sulphuric acid. 

For an earlier example, see the relation between Gay-Lussac and John Glover concerning production of sulphuric acid. Cf W.A. Campbell, Industrial chemistry, in C.A. Russell, ed.. Recent Developments in the History of Chemistry (London Royal Society of Chemistry, 1985), p. 243. 

The Gay-Lussac tower in sulphuric acid plants was invented in 1827 but first used in 1842. The Glover tower, invented in 1859 by a chemical plumber, John Glover (Newcastle on Tyne 2 February 1817-1 May 1902), came into general use in Widnes in 1868-70. Gay-Lussac s son Jules worked with Pelouze on salicin and with Liebig in Giessen on paraffin. ... 

Throughout the rest of the period under review the chemical technology came to Denmark from, or at least via, Germany 1873, beet sugar 1880 (approx.), Gay-Lussac and Glover towers in sulphuric acid production 1888, Portland cement and 1900 (approx.), refining of edible oil. 

A further method of extraction of the selenium from the mud is based on the solubility of the element in solutions of potassium cyanide, forming selenocyanide. The solution deposits selenium when acidified, and any sulphur is retained in solution as thiocyanic acid.2 Treatment with a solution of an alkali hydroxide, or fusion with sodium carbonate (the latter more especially for the extraction of selenium from the dust of the flues between the pyrites burners and the Glover tower), has also been applied, the mass being extracted with water in the latter case. The resulting aqueous solutions deposit selenium on atmospheric oxidation, whilst any extracted sulphur passes mainly to thiosulphate.3... 

The presence of much selenium in the Glover tower acid imparts a red colour to the liquid. The element can be separated by dilution followed by treatment with sulphur dioxide.5... 

---