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A big birthday for the Bakers

Summary

Celebrating this year some 50 years' service to the world's sulphur, chemicals and fertilizer businesses, British Sulphur nonetheless has to concede an even more auspicious birthday at the start of the millennium. H. J. Baker & Bro. is ­ currently celebrating a century and a half as a supplier of quality ingredients to the chemicals, fertilizer, food, and feed industries. Today the company's sulphur forming and loading operations supply many of the world's demand markets and the company looks ahead to many more years of international operations.

Abstract

In earlier days, the name Baker was perhaps best associated, in households throughout the United States, for the main output of the Baker Castor Oil Company in Jersey City, NJ. The company was also involved in marketing castor pomace – a residue from the production of castor oil and the company’s first fertilizer product. From those early days, H. J. Baker has evolved into a multi-service organisation marketing sulphur, feed ingredients, oils, fertilizers, and speciality industrial chemicals.

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Sulphate ­attack in concrete

Summary

While elemental sulphur has been used as an additive to concrete, to improve its properties, conventional concretes can be susceptible to attack by sulphates. The sulphate corrosion phenomenon has been recognised for years, but the mechanisms involved have been poorly understood. Recent investigations have shed more light on an old problem.

Abstract

Sulphate attack of concrete is a well-known but highly unpredictable phenomenon. On face of it, it should be more common; there are plenty of sulphates – both in cement formulations and in the environment – but cases of sulphate attack are comparatively isolated. When they do occur, however, the results can be devastating.

It is hard to make generalisations because sulphate attack cannot be fully characterised by a single mechanism and cannot be represented by a single or simple chemical reaction. In view of the virtual myriad of chemical entities among the constituents of cement and concrete, there is a complex set of chemical and physical processes that can take place.

The classical view of sulphate attack of concrete is that the attack is from the outside (external attack), in situations where the soil or ground­water contains sulphates, and that damage mainly occurs to buried concrete or where there is frequent access of the sulphate-laden groundwater. Chemi­cal and physical (micro-structural) modifications to the cement matrix take place that result in weakening or deterioration of the concrete in place.

To counter the phenomenon, a number of so-called sulphate resistance cements now exist – including pozzolanic and slag cements, but also Portland cements with reduced content of tricalcium aluminate (C3A in cement industry nomenclature) – but new manifestations occur that seem to defy conventional theories.

In recent years, sulphate attack has had an apparent association with the alkali/silica reaction (ASR), which has been known to cause cracking in circumstances where an alkali-sensitive aggregate comes into contact with a high-alkali cement type. But other mechanisms are also at work.

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Jacobs Comprimo ­introduces EuroClaus

Summary

By adding a key hydrogenation step to its modified Claus/SuperClaus process arrangement for treating H2S acid gases, Jacobs Comprimo Nederland opens the way for overall sulphur recovery efficiencies in excess of 99.5%

Abstract

It was in the 1930s that the free-flame thermal stage was first added to the original, catalytic, Claus pro­cess for the production of elemental sulphur from hydrogen sulphide, ultimately leading to the hugely important role that the so-called modified Claus process now has in sulphur recovery today. However, the recovery performance, or sulphur recovery efficiency (SRE) of the modified Claus process is still limited to 97-98%, because of thermodynamic equilibrium constraints.

As a result of this limitation, and in order to achieve greater SREs at the same time as further reducing air pollution emissions, a number of Claus plant tail gas treatment systems have been developed since the 1980s. The SuperClaus process, intro­duced by Comprimo/Gastec in 1988, increases overall SRE to 98.5-99.3% (depending on the feed gas) by combining the modified Claus with a selective oxidation step on the Claus plant tail gas, in order to convert the majority of the remaining hydrogen sulphide into more elemental sulphur. Jacobs Com­primo says that more than 90 Super­Claus units have been licensed since 1988, and that all units in operation have met or exceeded the guaranteed recovery efficiency.

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Aftermath of a storm

Summary

The US Frasch industry is about to close down. Last year it was Culberson; this year Main Pass 299 faces the end its career in sulphur production. Chris Cunningham reports on radical changes along the Gulf coast.

Abstract

The demise of the old Freeport Sulphur business seems an unlikely background for talk of increased security of brimstone supply in the US Gulf zone. But McMoRan Exploration’s (MMR) July announcement effectively to step away from its six million t/y capacity Freeport-McMoRan sulphur operations represents a major sea change in relations between sulphur buyers and suppliers along the Gulf coast.

The identity of a new owner for Freeport-McMoran was not clear by the end of August. However, the projected sale of the region’s biggest marketing and logistics operation, for all its major significance in the history of the sulphur industry, is one more step in a realignment of sulphur supply to the Florida area phosphate industry. The decision by a group of phosphate producers to make their own arrangements for solid sulphur supplies at the beginning of the year, and a new alliance between one of that group and a Gulf coast sulphur marketer, mark a determination by a fertilizer industry suffering cutbacks and falling export markets to set its own agenda for raw materials supply.

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Monsanto and sulphuric acid catalyst: 75 years' perspective

Summary

The first 75 years of sulphuric acid catalyst production at Monsanto has seen the evolution of both technology and total quality customer service. However, the beginning of the business was not always auspicious. As part of the 75th anniversary celebration, Atis Vavere reviews the history of the Monsanto catalyst business with an emphasis on new technology, lots of secrecy, a bit of controversy, and the growth of a young chemical company.

Abstract

The post-World War I economic climate was one of rapid expansion and innovation. The Mon­santo Chemical Works, based in St. Louis, Missouri, was right in the thick of this exciting business climate. The sulphuric acid business was extremely important during this period as many new processes required this chemical as a raw material or as a catalyst. The fledgling Monsanto Chemical Works, founded in 1902 and known for its manufacture of saccharin and aspirin, had entered the sulphuric acid production arena through the acquisition of the Commercial Acid Company plant in Illinois, just across the Missis­sippi River from the Monsanto Plant in the city of St. Louis.1 This acquisition gave Monsanto three lead chamber plants and an old-type contact sulphuric plant. There were shortcomings with both types of plants as the chamber units produced relatively weak 77 per cent sulphuric acid while the contact plant used expensive and unreliable platinum catalyst.

New catalyst technology appeared at the turn of the century as DeHaen obtained basic patents in Germany, Britain, and the United States which describe the application of vanadic acid and soluble compounds of vanadium deposited on such carriers as asbestos and pumice stone.2 During the ‘teens and early ’20s of the century, research teams at Badische Company received several patents on alkali-promoted, vanadium-based sulphuric acid catalysts on finely dispersed particles.2 During the early 1920s, there was a period of rapid research and development involving the contact sulphuric process and the catalyst systems.

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Demand from nickel refiners shapes up

Summary

The first of Australia's laterite nickel projects is emerging from from under a cloud of technical difficulties. As a result one of the world's biggest potential demand markets for sulphur is taking shape. Chris Cunningham reports on the potential for sulphur shippers as the first project to approach full commerical production formulates its supply plans.

Abstract

Up to mid-year much of the news emerging from Western Aus­tralia’s high pressure acid leach (HPAL) projects spelt out gloom, if not quite doom. Process and materials problems in various forms at the HPAL projects run by Anaconda Industries, Centaur Mining, and Pres­ton Resources raised doubts about the energence of what could be not only a major source of nickel and cobalt, but equally one of the biggest demand markets for sulphur to feed the acid leach operations.

Of the three, Anaconda now appears to have surmounted most of its major technical hurdles and is leading the way for other projects – its own and the other operators’ – towards the development of a mature Australian laterite processing industry. In turn, Anaconda can develop its role as the first of the HPAL projects’ operators to plan and execute the import of world-scale quantities of sulphur to feed its acid leach process.

Anaconda’s central tactic in aiming for first place in world nickel production is based on its “Three Nickel Provinces” strategy. The company aims to be producing between 50,000 and 80,000 tonnes of nickel from each of its laterite operations – Expanded Murrin Murrin, Mount Margaret and Cawse – with the prospect of a further two producing sites to follow.

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Oxygen boosts acid regeneration plants

Summary

There are a number of different thermal cracking processes for regeneration of spent sulphuric acid, and oxygen can be used in all such systems to advantage. In conjunction with process operators, gas supplier Messer Griesheim has developed methods to enable oxygen to be used in all existing types of reactors.

Abstract

In the last decades of the 20th century, the recycling of the valuable sulphur components of waste materials containing sulphuric acid has steadily gained in importance as a result of environmental regulations, which have constantly become more strict. In principle, there are several possibilities for recycling or regenerating the sulphuric acid contained in these wastes, and the methods that must be employed depend on the nature of the spent acid itself and the original processes in which it was used. The three main options are:

  • direct use of the spent sulphuric acid
  • use of spent sulphuric acid after it has been concentrated and, optionally,
    • after impurities, especially metal sulphates, have been removed
    • or organic compounds have been destroyed oxidatively
  • regeneration of sulphuric acid or oleum from spent sulphuric acid, sulphates or other sulphur-containing waste by cracking thermally and converting the SO2.

The costs per ton of sulphuric acid increase greatly in the order of the alternatives given above. Where it is possible, direct re-use of spent acid is clearly the cheapest option. There are several methods for concentrating sulphuric acid and their applicability depends essentially on the concentration and nature of the impurities in the waste acids. Costs of concentration therefore vary according to the technical difficulty of the steps involved, but concentration will always be preferred over regeneration, if it is a practicable proposition.

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Spent catalyst ­recycling – an intricate labyrinth

Summary

The notion of recycling spent catalysts is not new, but new disposal regulations brings the issue into sharper focus. On the face of things, transition metal catalysts – such as those used in oil refinery hydrotreating/hydrodesulphurisation processes – have metal contents that bear a high intrinsic value, but that doesn't necessarily mean that recycling will be a profitable undertaking for refineries. Chris Cutchey, agent for Nickelhütte Aue, explains why.

Abstract

The disposal of spent catalysts used to be a simple matter. Noble catalysts were serviced by the suppliers or some users played the markets. Other catalysts could be collected by your friendly neighbourhood used-catalyst trader who asked very few questions. Those that contained nothing of value were just tipped in a local dumping area.

Those days are new long-gone and will never be seen again. Almost all spent catalysts are now classified as “hazardous waste” for transport purposes. The various Duties of Care, Basel Convention, Transfrontier Ship­ment of Waste regulations, and hazardous shipment rules now mean that the lot of the chemical processor or oil refiner is no longer an easy one.

It has become essential to ensure that such material is properly looked after “from the cradle to the grave”, and the selection of a service provider and recycler is now of overriding importance. Because such constraints are very likely to become even more complex and difficult, the more forward-looking operators are now work­ing to build long-term arrangements into their future financial projections.

While catalyst disposal is one side of the environmental coin, the other is that recent moves by regulators means, for example, that the sulphur contents of motor fuels will be driven down, leading to extra demands for catalytic hydrotreating/hydrodesulphurisation at oil refineries around the world. The increased level of processing envisaged cannot fail to lead to increased levels of spent catalyst to be disposed of.

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