A significant reason why there are so few companies producing ultramarine blue in the world is the cost associated with reducing sulphur dioxide emissions to the atmosphere. The global effects of the resultant acid rain are well documented and there are targets for reducing sulphur dioxide emissions in many countries. Whilst it can be argued that ultramarine blue is a minor contributor compared to power stations and motor vehicles, there are technical solutions available, which can reduce emissions from ultramarine blue factories to a bare minimum. Any manufacturer and user of ultramarine blue pigments which wishes to claim to be environmentally friendly has no excuse for not practising responsible care in this respect.
During the 1990’s, Holliday Pigments became the first company to introduce abatement equipment to the ultramarine blue process. The main environmental impact associated with manufacture was the emission of considerable quantities of sulphur dioxide to the atmosphere. Every year, thousands of tonnes of this toxic, acid rain forming gas were released through tall chimneys into the environment. Whilst the tall chimneys ensured the gas dispersed to safe ground level concentrations they could not overcome the problem of the gas producing acid rain. To counter this problem, in 1990, the management of Holliday Pigments decided to install flue gas desulphurisation equipment at their Comines site.
At this time, the best flue gas desulphurisation process available was the Sulfacid process supplied by the Lurgi Company. By using a fixed charcoal bed with a counter current of water, this process absorbed some of the sulphur dioxide from the exhaust gas to produce a weak sulphuric acid solution. The installation of the process at Comines resulted in a 50% reduction of sulphur dioxide.
By the mid 1990s, investment plans were approved for the installation of a flue gas desulphurisation unit at the Hull site. However, by this point in time, the best available technology for flue gas desulphurisation had changed to a catalytic sulphuric acid process. This superior process, with the ability to virtually eliminate sulphur dioxide emissions, was therefore installed at the Hull site.
The process utilises a catalytic reaction to convert sulphur dioxide to sulphur trioxide. Unlike sulphur dioxide, sulphur trioxide is readily condensable and, therefore, can be easily separated from the rest of the exhaust gas mixture. This leaves, after separation, a cleaned exhaust gas stream with just 100 milligrams of sulphur dioxide per cubic metre and a concentrated high quality sulphuric acid. (The sulphuric acid produced by the system is so pure that it is supplied to the pharmaceutical industry for use as a raw material). Unlike many flue gas desulphurisation plants, the chosen system only requires the input of energy to function (as compared to lime scrubbers that require the input of raw materials). Although an energy input is required to get the process going, the overall process is a net producer of energy and with the installation of waste heat recovery systems the process has virtually eliminated the use of natural gas boilers at the site.
In 2003, a new sulphur dioxide abatement plant was approved for installation at the Comines site. This is now fully operational and achieves the same performance as the Hull facility.

October 7, 2004 - Holliday Pigments, the world’s largest manufacturer of ultramarine blue pigments, today announced the official opening of its flue gas desulphurisation (FGD) plant in Comines, North France. The company is the only ultramarine manufacturer in the world to have invested over $30 million in FGD plants proving its dedication to environmentally sound manufacturing. The new plant will reduce the sulphur dioxide emissions inherent in the manufacturing process by more than 99.5%.  Similar to Holliday Pigments’ existing FGD plant in Kingston upon Hull, UK, the unit oxidises the sulphur dioxide in a two-stage catalytic conversion process consisting of platinum and vanadium pentoxide. This produces high quality sulphuric acid with a concentration of 96%. Negligible waste is produced.  At the inauguration ceremony, guests were given a tour of the site and listened to speeches given by local dignitaries including Mr Aribaud, Regional Prefect, Mr Ségard, Mayor of Comines and Mr Daubresse, secretary of state for housing and Vice President of the Lille Métropole. Speakers praised the investment in the area and Holliday Pigments’ commitment to the environment.  Christian Duhayon, MD Holliday Pigments, “We are delighted to open our new FGD plant which will have such positive implications for the environment. Stringent environmental policies and responsible manufacturing processes lie at the heart of our culture. We believe that this sets us aside from many other companies and we are confident that we have set a benchmark for the rest of the industry to follow.”  Holliday Pigments believes that looking after the environment is a global responsibility. In an increasingly environmentally conscious marketplace, it is not just the immediate product credentials that are scrutinised. The environmental impact of a product should be judged throughout its entire life cycle – from cradle to grave.  The process involved in manufacturing Holliday Pigments’ ultramarine blue is a good example. Its raw material is predominantly china clay quarried in Cornwall. Quarry sites, when finished with, are ‘returned to nature’ in ways benefiting people and nature. The sulphur dioxide emissions produced during manufacture are then dealt with on site, leaving a product that has minimal environmental impact throughout its entire life cycle.  “The investment in FGD technology consolidates our position as a company that not only offers a truly unique colour, but also stands apart due to our industry leading environmental credentials,” Continues Duhayon.

www.uic.fr - New unit of desulfuration of fumes - The HOLLIDAY PIGMENTS SA company, located in Comines in the North of France, inaugurated a new unit of desulfuration of fumes generated by the calcination of the ultramarine pigment on 17 th September.  The SULFOX HK unit was built by the Austrian company KANZLER VERFAHRENSTECHNIK GmbH. It is the Best Available Technique (MTD), whose refining capacity is of more than 99.5%. The sulphurous anhydrid is oxidized on a double catalytic bed made of platinum and vanadium pentoxide. The sulphuric acid produced has a concentration of 96% and is of excellent quality. No waste is produced.  The maximum concentration of SO₂ coming out at the end is of 150mg/Nm³. The project cost 7 million euros and is the object of financial help from the FEDER of 1,686Keuros.  The company has 120 staff. The performances of this new unit make it possible to foresee future expansion projects.