This mild steel lead lined tank and enameled pan top were built at some point between the late 19th century and early 20th century at the Levenstein/Blackley dyeworks which was based in Manchester.

The tank is approximately 4 feet 6 inches in diameter, 4 feet 6 inches deep and weighs around one and a half tons. The enameled pan fits on top of the steel tank, and at the bottom of the tank is a porcelain hole where a charge tap would have been installed. Internally, the tank also had lead coiling and lead covered grid agitator to facilitate the mixing of cod liver oil and sulphonic acid.

This mild steel lead lined tank (also known as a sulphonating pan) was originally installed at the Imperial Chemical Industries’ Blackley dyeworks which was located in Manchester, for purpose of producing ‘Kromaline’. The Blackley dyeworks was once one of the country’s oldest and historically significant sites of industrial chemistry and was previously the Levenstein Ltd dyeworks which had been in operation since the 1830s.

During the first half of the 20th century was a major producer of ‘Kromaline’, a type of sulphonated cod liver oil. Kromaline was used to treat leather to make it more durable, elastic and pliable, and was produced by mixing cod liver oil with a prepared sulphonic acid solution which would chemically alter and ‘sulphonate’ the oil. This sulphonation process took place inside tanks such as this one, the lead lining preventing the acid from eating away at the steel casing.

The mixture would then be neutralized and stabilised over the course of two days with the help of diluted salt and caustic solutions. Finally, the finished Kromaline would be pumped to vats kept in an external storage shed. The whole process took approximately two and half days and would also produce by-product oils which were also useful such as Turkey Red Oil or Oleine sulphonation.

The Blackley dyeworks was finally closed in the 1980s after nearly 150 years of history, by this point operating as Imperial Chemical Industries’ organics research division.