Coke Smelting

Severe restrictions (enforced by legislation in the 16th century) on smelting iron using wood to fuel furnaces had a disastrous effect on the production of iron. No new furnaces were built and old ones allowed to decay. Many called for the banning of iron production completely.

Though woodland was being decimated, iron implements of peace and war were an integral part of life that could not be dispensed with, resulting in the importation of vast amounts of steel and iron from Sweden, Germany and Spain. Ironic, given that the Spaniards in particular coveted the quality of English made cannons.

English iron manufacturers were naturally annoyed at the loss of production and sought alternatives to charcoal to fuel their furnaces.

Many doubted that coal could be used for smelting iron, and the first to try was German mining expert Simon Sturtevant. In his Treatise of Metallica he states: 'it will be the most profitable business and greatest invention in England', but his failure resulted in John Rovenzon being granted a patent for making iron by the same process in 1613. He had a true grasp of the concept but failed too.

In 1620 a patent was taken out by Lord Dudley on behalf of his son, Dud Dudley, for the 'melting of iron and making iron-bar by coal'.

Dud Dudley was born in 1599. The son of Edward Lord Dudley, of Dudley Castle, he gained considerable knowledge of the processes of manufacture by working in his father's ironworks as a teenager. Though an industry of mostly small wares thrived within a ten mile radius of Dudley Castle, the lack of fuel almost brought it to a stand still.

The Earl encouraged his son's speculations regarding the improvement of iron manufacture and ensured his education put his practical skills to good use. In 1619 he recalled him from Baliol College, Oxford to take charge of ironworks at Pensnet in Worcestershire.

He soon realised that the lack of wood for fuel warranted a new approach to iron manufacture, and he adapted his furnace to use pit coal. Having subjected the coal to a similar process to that of charcoal, he was successful in producing 'marketable' iron, though the quantity was small.

The success of the trials prompted him to write to his father, who was in London at the time, asking him to obtain a patent for the process from King James, which was granted on the 22nd February 1620 (patent No. 18) in the name of Lord Dudley himself. A year after the patent was granted Dud Dudley was commanded to send up to the Tower a quantity of his new iron for trials. After its qualities were tested it was pronounced as good merchantable iron.

Many ironmasters petitioned King James to put an end to Dudley's enterprise, saying it was a dangerous innovation. They rejoiced when the Great May-Day Flood virtually wiped out his principal works. Undaunted, Dud Dudley repaired his furnaces and continued to produce cheap quality iron.

Fresh outcries were raised against him by other ironmasters who partitioned King James to revoke Dudley's patent, but he was ordered to again send up to the Tower samples of all his iron bar. His critics were silenced when thorough trials again confirmed its quality. This success evoked great hostility from the charcoal ironmasters, who eventually hounded him from the county.

He set up a furnace at Himley in Staffordshire, but was forced to sell the pig iron he produced to the charcoal ironmasters as he did not have the means to forge it himself. They took the opportunity to seize his stock and disparage the quality of his iron.

He set up another furnace at Sedgeley in the same county, which was the largest ever built. It operated on his improved principles and produced seven tons of pit-coal iron a week; the most ever produced in Great Britain at that time.

Just as he was about to start large-scale operations a gang of rioters, stirred up by the charcoal ironmasters, wrecked his furnace and ruined him financially, leading to his being held in London as a prisoner.

In desperation he petitioned Charles 1 about the advantages to the nation of his great invention, which had brought him no financial rewards, only persecution and suffering. The king took pity on him and granted him a new patent in his own name in 1638. He had scarcely started smelting iron again, when the English Civil War broke out.

In 1643 he acted as a royalist military engineer and set up the fortifications of Worcester and Stafford, and provided the ordnance. At the taking of Lichfield he was made Colonel of Dragoons and accompanied the Queen with his regiment to Oxford. He rose to the rank of General, and was described as a valiant soldier.

With the civil over, even Cromwell himself with partner Major Wildman and others set up furnaces in the Forest of Dean to try and smelt iron using pit coal to fuel the furnace, but none were successful.

Many new furnaces and works were set up in Bristol to which Dud Dudley was invited, knowing that he held the great secret. He told them they would not succeed with the methods they were using - none did.

Dud Dudley died in 1684 at the age of 85, and took his coke-smelting secret to the grave.

Fact File

Coke Smelting