Denis Fletcher Kelsall

September 29th, 2020

Denis Fletcher Kelsall (1918-1982), chemical engineer, was born on 10 February 1918 at Broadbottom, Cheshire, England, son of William Fletcher Kelsall, police constable, and his wife Annie Elizabeth, née Mason. He attended (1930-36) Altrincham Grammar School for Boys, where he became a prefect and played football in the first XI. Awarded state and county scholarships to Queens’ College, Cambridge (BA, 1939; MA, 1943; Ph.D., 1969), he gained first-class honours in both parts of the natural sciences tripos. He worked for Imperial Chemical Industries Ltd for a short period before joining the Royal Air Force in 1941 and serving as a pilot. Commissioned in June 1943, he was promoted to flying officer in December. On 1 January 1944 he married Bessie Dutton at the parish church of St Ambrose, Widnes, Lancashire.

Demobilised from the RAF in 1945, Kelsall studied at Cambridge University Training College for Schoolmasters and in 1946-47 taught at his old school. He then took up an appointment as principal scientific officer in the chemical engineering division of the Atomic Energy Research Establishment, Harwell. Part of his time was spent on secondment in Canada, where he commenced his work on mineral separation techniques. In 1952 he was awarded the Moulton medal of the Institution of Chemical Engineers for his research at Harwell on hydraulic cyclones. His study of cyclones was to lead to his becoming the first non-American recipient of the Robert H. Richards award of the American Institute of Mining, Metallurgical, and Petroleum Engineers, in 1977.

Appointed chief concentration metallurgist for Rhoanglo Mine Services Ltd in 1953, Kelsall worked for the company at Kitwe, Northern Rhodesia (Zambia), before joining the chemical engineering section, division of industrial chemistry, of the Commonwealth Scientific and Industrial Research Organization in Melbourne in 1959. At first his work spanned diverse fields but he soon came to concentrate on size separation and then on grinding and eventually on flotation processes for separating minerals.

Kelsall became chief of the CSIRO’s division of chemical engineering in 1974, by which time he had written or co-authored some forty-two scientific papers. For a time (1979-81) he was also chief of the division of applied geomechanics. Active in the affairs of his profession, he was the leading author of a workshop course, `Exploiting the Modern Approach to Crushing, Grinding, Classification and Flotation’, held by the Australian Mineral Foundation in 1975. In 1976 he was elected a fellow of the Australian Academy of Technological Sciences, for whom he convened a symposium on Australia’s mineral resources in 1979. He was a member of the Institution of Chemical Engineers, the Institution of Mining and Metallurgy, and the Australasian Institute of Mining and Metallurgy.

Although Kelsall had become an Australian citizen in 1970 and expressed strong loyalties to the Australian way of life, he always regarded himself as a `scientific missionary’. `Kelly’, as he was known in Australia, lived an organised, disciplined life and expected no less of his professional colleagues. For many years he took part in amateur theatricals as a member of the Beaumaris Players. Until his final year he played golf and jogged, combining the latter with exercising his dog. Survived by his wife and their three daughters, he died of cancer on 15 April 1982 at East Bentleigh and was cremated.

Citation details

Ian D. Rae, ‘Kelsall, Denis Fletcher (1918–1982)’, Australian Dictionary of Biography, National Centre of Biography, Australian National University,, published first in hardcopy 2007, accessed online 6 May 2020.