VIRTUAL VISIT : ULTRAMARINE MANUFACTURE AT HOLLIDAY PIGMENTS, HULL

MANUFACTURE IN HULL

The Reckitts

In 1842 Isaac Reckitt, a Quaker, moved from Nottingham to Kingston upon Hull in order to rent a small starch factory in Dansom Lane in the city, and to set up the company known as Reckitt & Sons. Starch was used as a stiffening agent for newly-washed cotton shirts, pillow cases and tablecloths. In its first ten years, therefore, Reckitt & Sons' factory was manufacturing one laundry product. In 1852 it began to produce another one.

Fabrics made from natural fibres such as cotton turn unattractively yellow as they get older, probably as the result of oxidation. Reckitt & Sons hit on the idea of adding a very blue colour to the fabric, so that the fibres would reflect both yellow and blue light. When yellow light and blue light are mixed, white light results. The reflected white light makes the fabric appear to be white and the blue colouring matter was therefore acting as a whitening (or brightening) agent for the fibres. Reckitt's product, sold as laundry blue or dolly blue (the washing tub to which the colorant was added, was called a "dolly tub"), consisted of a mixture of synthetic ultramarine and bicarbonate of soda (sodium hydrogencarbonate), packed in a little cotton bag containing a wooden rod to allow it easily to be taken from the hot washing water. Reckitt's Blue soon outsold the original laundry starch and the other products of the Dansom Lane works which included stove blacking, boot polishes and metal polishes such as 'Brasso', and the little cotton bags were on sale for many years until the 1950s when they were replaced by the organic compounds called optical brighteners. The paper industry still uses ultramarine in making good quality white paper. The natural yellow colour of cellulose in the paper is eliminated by the blue pigment in exactly the same way as Reckitt's Blue acted as a cotton whitener.

Originally Reckitt & Sons had to import synthetic ultramarine from France or Germany but this supply diminished during the Austro-Prussian Wars of the 1860s and the company would make its own. In 1884 ultramarine manufacture began at the new purpose-built Morley Street factory where it has continued to the present day. The current annual output being of the order of 9000 tonnes. For many years the site was the property of Reckitt's Colours, a branch of Reckitt & Coleman, but now its owners are Holliday Pigments, a division of the Yule Catto Group. A second Holliday Pigments factory is situated at Comines in France where 6000 tonnes of ultramarine are produced annually. Holliday Pigments are therefore responsible for 60% of the world production of the synthetic pigment. The company also produces a violet form and a pink form of the pigment by chemical modification of the structure of ultramarine. Ultramarine Violet is made by heating the blue pigment with ammonium chloride and Ultramarine Pink by heating with hydrochloric acid. In both cases the sulphide groups are replaced by chlorine atoms, the more chlorine atoms being introduced, the more red is the colour of the product. The red and violet varieties, however, have poor tinting strengths as compared with the parent pigment.

The Morley Street Process

The Morley Street factory was built close to the tidal River Hull which serves as a large-scale source of water for the process and as a means of disposal of aqueous effluents. Manufacture continues around the clock every day in the year apart from Christmas Day. Although the heart of the process is the heating of the reactants and the cooling of the product in a kiln for a 21-day period, ie a 'batch process', continuous operation is achieved by having a series of kilns in staggered use, one being filled while another is being heated, a third is being cooled and a fourth is being unloaded.

The dominant landmark at the site is the 141-metre chimney (about 450 feet in height) through which sulphur dioxide from the kilns is discharged into the atmosphere, although now in much smaller quantities than it used to be. A tall chimney discharges gases at a height above the ground at which there is a high probability that the effluent will disperse thinly over a large area before returning to ground level as an aqueous solution.

Feedstocks

The raw materials for the present-day manufacture of synthetic ultramarine are the same as those which Guimet used in the 1820s, china clay, sulphur and soda ash (sodium carbonate).

sulphur
china clay
soda ash (sodium carbonate)

China clay (a sodium aluminium silicate) for the Hull plant is quarried in Devon and is delivered daily by lorry to Morley Street.

Sulphur arrives at Morley Street in the molten state in heated tankers, rather like huge mobile thermos flasks. These vehicles make the comparatively short journey from an oil refinery on the South Bank of the Humber estuary where the sulphur is produced as a by-product of the petroleum industry. Petroleum oil is therefore a Raw Material in the manufacture of ultramarine.

Soda ash (sodium carbonate) is manufactured, probably at Winnington in Cheshire, by the Solvay process in which the raw materials are brine (aqueous sodium chloride), carbon dioxide and ammonia gas:

NaCl(aq) + CO2(g) + NH3(g) + H2O(l)   —>    NH4Cl(aq) + NaHCO3(s)

2NaHCO3(s)    —>   Na2CO3(s) + H2O(g) + CO2(g)

The Morley Street Operation

The production of the pigment consists of two parts, the Dry Process and the Wet Process.

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