In 1920 Electrolytic Refining and Smelting had been in operation for eleven years, and facilities were under construction for the next stage of the production complex – the manufacture of sulphuric acid. That acid was to be used by ER&S in refining and other processes, by MM and, later, to be used in other industries not as yet established – Australian Iron and Steel, John Lysaght and others. On a larger scale, the plant itself would use it for the manufacture of single superphosphate (SSP) by the addition of concentrated sulphuric acid to phosphate rock, from both local and overseas sources. The plant was to be operated by Australian Fertilisers Ltd, (AFL) set up in 1920 and jointly owned by ER&S and its principal parent, Mt Morgan Mining Company, with a capital of £500,000. It replaced an older, smaller plant owned by George Shirley Limited in Balmain following the takeover of that business by Mt Morgan. AFL commenced operations in 1921. 

Australian Fertilisers Ltd, Port Kembla 1921
(Courtesy of the Wollongong City Library and the Illawarra Historical Society Collections (P08922)

The Acid Plant

The new facility was no small undertaking, with a budgeted cost around £200,000. Its initial design capacity was 30,000 tons of SSP per year, with an aim to extend to 50,000 tons per year. Acid manufacture could be based on either raw sulphur (“brimstone” at some 99% sulphur) or pyrites – sulphide ores. Four furnaces were provided to generate the sulphur dioxide-laden gases for the acid process – two rotary furnaces and two Herreshoff furnaces with a total capacity of 26 tons of sulphur daily. Their off-gases fed into a conventional three stage lead chamber process embodying Glover towers, lead chambers, and Gay-Lussac towers. The two Glover towers were 12 feet square by 28 feet tall; of three lead chambers, one was 25 feet by 25 feet and 100 feet long, and the two others each 25 feet by 25 feet and 50 feet long. The final stage Gay-Lussac washing towers were each 12 feet square by 28 feet tall. The minimum capacity of the plant was 15,000 tons of chamber acid (around 74% concentration) per annum.

Details of the lead chamber process for acid manufacture may be found here

Making Fertiliser 

The fertiliser process itself was a simpler one involving carefully slurrying the crushed phosphate rock with acid, and then allowing the mix to stand (after gravity feeding to storage) until solid and able to be handled with the reaction complete. Final stages were largely crushing where necessary, packaging and dispatch. The product was single superphosphate, SSP.

Material storage building areas were large, as would be expected in an industry with a substantial seasonality in its demand. The feed material storage building was 380 feet by 75 feet, and product storage building 192 feet by 60 feet by 35 feet high. The plant’s official opening dinner on 13th August 1921 was held in the latter, one attendee describing the 500 guests seated at table as looking “ a dolls’ banquet” when viewed from one end of the building.

The commencement of the plant’s operation drew much attention from the primary production community, coming as it did at a time when expanding primary production output and productivity through such avenues as fertiliser use was a clear and common objective. 

New Owners

Less than seven years into the life of the plant its ownership was wholly changed, with the removal of all equity ties between AFL and ERS. As the result of Mt Morgan Mining’s inability to continue operations, and its subsequent liquidation, in early 1928 AFL’s co-owners Mt Morgan and ERS sold all the shares in AFL (valued at £380,000) to a consortium comprising Mt Lyell Mining and Railway Co Ltd, Nobel Australia Ltd (later ICI Australia) and Cuming Smith Co Ltd.

Cuming Smith were the first producer of SSP in Australia, in 1910 in their Bassendean (WA) plant.  

Development and Troubled Markets

At the time of the ownership change work was already in progress on extensions to the plant, resulting by mid-1929 in a fifty per cent increase in capacity, as the result of spending what was termed “..a very large sum of money”. Unfortunately, external events were much less positive, resulting in the plant being closed in early 1931 as the effects of the Depression on primary producers impacted also on fertiliser demand, after arguments on the supply of fertilizer to needy farmers.

The plant started up again later in the year, and it was not long before further capacity was installed. The company acquired land formerly occupied by the Mt Lyell Port Kembla cokeworks in 1937, and over 1938 and 1939 plant production capacity was nearly trebled. Notwithstanding these increases, profits over the years of the early 1940s showed successive declines. The latter part of the 1940s were also troubled by issues including industrial disputes, and shortages of sulphur feedstock. 

Postwar Growth and Contact Acid 

By 1951 work had once again started on extending plant capacity, then already at 80,000 to 90,000 tons per annum. On the fertilizer side, work included additional phosphate storage and crushing facilities, and dispatch facilities. On the acid side, the notable addition was to be a contact acid plant, to bring the ability to produce a 98% sulphuric acid as compared to the 74% previously available through the chamber process. The intended increase in acid capacity reflected the much broadened role the acid supply now served for a range of companies and applications around the Port Kembla industrial complex. The proposed new plant, in keeping with government pressures, was designed to operate on pyrites as feedstock, as well as the increasingly problematic raw sulphur.

Bagging superphosphate SSP
(Courtesy of the Wollongong City Library and the Illawarra Historical Society (P16477) Collections)

It appears that the contact acid plant component of the 1951 upgrade was not completed. Rather, a new contact acid plant was commissioned in 1960, with design features enabling it to potentially utilise SO2-rich gas from the copper ore sinter machine then recently installed at ERS. In the early 1970s, a second contact acid plant was built, which was later converted to process refinery residues and remain as the last of the former AFL plant in use. In later years, attempts were made to feed the acid plant with sinter plant off-gas from iron ore sintering at the nearby steelworks. The attempt was not successful. However these attempts to couple acid plants with waste gas cleanup from operations such as smelting and sintering were indicative of the direction the acid industry would take in later years, as noted below.

The period of the mid 1960s saw fertiliser demand exceeding the available AFL plant capacity, partly because of a three week strike at the plant, and partly because of capacity limitations which were to be remedied with the new acid plant. (A new phosphoric acid concentrator was installed for the same purpose.)

Aerial View of Cockle Creek works, Sulphide Corporation
Courtesy of the Newcastle City Library (Image Nr 18_985_00301587) Collection)

Fertiliser was actually purchased from other ICI operations in Victoria, and supplied to AFL’s NSW customers. Five years later, however, production at the Port Kembla site (which had grown to include phosphoric acid and other fertiliser products) was reduced to cover single superphosphate (the plant’s original product) only. This was done as a part of product rationalisation with the former Sulphide Corporation fertiliser plant at Cockle Creek in Newcastle, which AFL had acquired in 1969. Ironically, AFL and the Cockle Creek plant had pooled production agreements for over 30 years. 

Production of fertiliser (now only single superphosphate) ended in November 1982. A variety of factors contributed to this end, after some 60 years of production. The first was a reduction in demand for locally manufactured superphosphate fertiliser, through competition from cheaper more complex fertilisers. The second was competition on the feedstock side. As an incidental outcome from rising environmental standards, demands for SO2 controls on smelters and related plants have increased notably. Recovery of SO through its conversion to acid has proved to be the most economic way to address those environmental issues while at the same time generating a useful product from what was otherwise a noxious byproduct of metallurgical operations. The end result has been the virtual disappearance of industrial scale acid manufacture from sulphur or pyrites input materials.

The Port Kembla site now has a sulphuric acid handling facility, and a contact acid plant which originally manufactured sulphuric acid in the ‘conventional’ manner of the day, now modified to provide a recycling and processing service for used sulphuric acid from refineries. Having been effectively owned by ICI Australia and its successors for many years, the site is now owned by IXOM Port Kembla, a firm created when the Chemicals Group of Orica Pty Ltd split off as an independent entity in 2015.