Sulphuric acid lead chamber process

Figure 10.5. The Lead Chamber process for the manufacture of sulphuric acid...

This commonest derivative of sulphur trioxide and the most important of all acids from a technical and commercial aspect, has been known from early times, although its production on a large scale and at a low price dates from the success of the lead chamber process of manufacture, which revolutionised chemical industry in the early part of the nineteenth century. 

Nitrosulphonic Acid, Nitrosylsulphuric Acid or Nitroso-sulphuric Acid, NQ2.S02.0H.—In 1806, Clement and Desormcs, during the manufacture of sulphuric acid by the lead chamber process, observed the formation of a crystalline solid, to which the names nitrosulphonic acid and nitrosylsulphuric acid were later given the term chamber crystals, however, is still commonly applied to this acid.6 The composition and nature of the acid were first investigated by Weber,7 and by Michaelis and Schumann.8... 

It is fairly generally believed that nitrosulphonic acid plays an important part in the lead chamber process for the manufacture of sulphuric acid (see p. 153). The vapour pressures of mixtures of sulphuric acid with nitrous or nitric acid or with both these acids, within the range occurring in the chambers, increase with the nitrogen acid content and with rise in temperature, and the total pressure is always higher than the sum of the individual pressures, especially when the sulphuric acid is concentrated, for nitric acid - sulphuric acid mixtures this may be explained 1 by the occurrence of the following... 

The production of sulphuric acid was commercialized in the mid-18th century. In the so-called lead chamber process the oxidation of SO2 into SO3 was catalyzed by NO. The acid produced is not very concentrated. The raw material used was elemental sulphur from Sicily. Later pyrite was used because of its lower price. 

The production of sulphuric acid was commercialised in the mid-18th century. In the so-called lead chamber process the oxidation of SO2 into SO3 was catalysed by NO. The acid produced is not very concentrated. The raw material used was elemental sulphur from Sicily. Later, pyrite was used because of its lower price. One of the consequences was a much higher impurity level in the feed to the reactor. As early as 1831 a process was patented in which SO2 was oxidised in the presence of finely divided platinum. The commercial application, however, was strongly delayed due to technical difficulties, the major one being catalyst poisoning. 

The Lead Chamber process for the manufacture of sulphuric acid was developed in the 1740s by John Roebuck, then based in Birmingham. Production of this key commodity rose steadily. By the 1820s, British annual production had reached 10,000 tons of 100% acid. By 1900, Britain was producing one quarter of the world s output with an annual production approaching one million tons. 

Until the 1930s, sulphuric acid was manufactured by the lead-chamber process, but this has now been replaced by the contact process (catalytic oxidation of sulphur dioxide). It is extensively used in industry, the main applications being fertilizers (32%), chemicals (16%), paints and pigments (15%), detergents (11%), and fibres (9%). 

Sulphuric acid was produced by the lead chamber process, originally from Sicilian sulphur, then from the cheaper pyrites. As the demand for sulphuric acid grew, Montecatini Mining Co. Limited (founded in 1888, and the forerunner of the present Montecatini Company) increased pyrites mining at the Boccheggiano field in Tuscany. In 1910 it acquired a monopoly over pyrites in Italy. Sulphur dioxide was produced, at first in Maletra, and then in Herreschoff or Kauihiann kilns. 

The invention of the lead chamber process for the manufacture of sulphuric acid by John Roebuck in 1746 is regarded as one of the most significant developments of the Industrial Revolution. Over the next century... 

The use of zinc blende and mixed zinc ores as a convenient source of sulphur dioxide for sulphuric acid manufacture has been advocated. The residue from the roasting is often more valuable than in the case of pyrites, but the roasting process is more troublesome and the presence of fluorspar in the blende exerts a deteriorating influence on the lead chambers.2... 

Manufacture.—The world s annual output of sulphuric aeid is approximately 10 million tons, and this huge amount is supplied almost entirely by the lead chamber and contact processes. The dry distillation of green vitriol as a technical operation has now been abandoned. In Great Britain and Northern Ireland the output for the year 1928 in terms of 100 per cent, sulphuric acid and including oleum was 928,000 tons. ... 

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. 

Theory of the Action in the Lead Chambers.—The actual mechanism of the chemical process in the lead chambers has for years been a matter of much conjecture and controversy. The formation of unstable intermediate compounds which subsequently undergo decomposition with production of sulphuric acid is almost universally accepted, but unfortunately there is no general agreement as to the identity of the intermediate compound or compounds. 

The limit of concentration attainable by any of the foregoing methods is about 98 per cent. If acid of higher concentration than this is required, acid of 97 to 98 per cent, strength can be partially frozen,2 when the colourless prisms which separate contain 99-5 to 100 per cent. H2S04 and constitute the frequently so-called, but misnamed, monohydrate. Owing to the success of the contact process for the preparation of sulphur trioxide and of fuming sulphuric acid, the production of highly concentrated sulphuric acid has been rendered so simple a matter that concentration of the lead chamber acid is of diminished importance. The main value of the chamber process lies in its economical production of a not necessarily very concentrated acid. There are indications, however, that by a suitable combination of the two processes, an even more economical production of concentrated acid may be obtainable (see p. 162). 

---