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Chlorine & caustic soda in Australia (& hydrogen chloride)



Chlorine (Cl2), also known as molecular chlorine, is a greenish yellow gas with an irritating odour. Chlorine is used extensively for purifying domestic water and effluents. It is an important industrial chemical used to produce pesticides, disinfectants, chlorine bleach cleaners, swimming pool chemicals, PVC plastic, synthetic rubber and other chlorinated chemicals. An important application is for the manufacture of titanium dioxide pigment.

There are minimal imports of chlorine given the hazardous nature of this gas. Vinyl chloride monomer (VCM) is imported by Australian Vinyls Corporation. Imports of VCM contains about 130 000 tonnes of chlorine with other chemicals imported containing a further 30 000 tonnes of chlorine.

The process of manufacture uses electricity and salt. In manufacture, for every 80 tonnes of caustic soda, 71 tonnes of chlorine and 2 tonnes of hydrogen are co-produced. Each tonne of caustic soda requires around 2200 kWh of electricity and 1.55 tonnes of salt.

There are three processes of manufacture. bulletMercury cell - the oldest technology employed which has been largely closed down around the world being less efficient and polluting. bulletDiaphragm cell - the dominant technology. bulletMembrane cell - preferred technology for new plants and now in Australia's for its smaller plants. Details of manufacture in chloralkali plants.

Chloralkali production in Australia is primarily to produce chlorine, which is expensive and hazardous to transport - the caustic soda is a by-product. Production centres are therefore located in the plant or, in the case of titanium dioxide pigment, over the fence and used for the manufacture of titanium dioxide, herbicides, hypochlorite and water sterilisation.

Orica operates: bullet9 000 tonne membrane cell plant at Yarwun (near Gladstone) Queensland. bullet14 000 tonnes of chlorine at Yarraville, near Melbourne, Victoria using mercury cell. Surplus chlorine is used to produce Cerechlor, a chlorinated hydrocarbon used in electric cables as a fire resistant plasticiser (like the phthalates plasticisers). By year 2000 it will be replaced by a larger 30 000 tonne membrane cell unit being constructed at Laverton North Victoria. bullet$100 million chlor-alkali plant will be built at Laverton North. using membrane production technology. The 30 000 tonne plant is scheduled for commissioning by the end of 2000, replacing the company's older chlor-alkali plant at Yarraville.
The plant will manufacture: bulletchlorine which is used extensively in a wide range of applications, including drinking water purification. bulletsodium hypochlorite for treating swimming pools ('pool chlorine'); bullethydrochloric acid which is used in steel manufacture and bulletcaustic soda which is used in the manufacture of paper, detergents and soaps, and in food processing.  bulletchlorine that will be road freighted to Botany NSW. (Quantities not known but could be around 10 000 tpa which raises question of why the surplus capacity).
bullet35 000 tonnes from mercury cell plant (1940) at Botany New South Wales to produce chlorine, hydrochloric acid, hypochlorite. Plant to be replaced by a 30 000 tonne membrane cell during 2000. (Chlorine has been used at Orica's Botany plant to produce chlorine chemicals including VCM and EDC until 1996, 1998 respectively).

Nufarm Coogee for titanium dioxide at:

bulletKwinana Western Australia, producing 17 000 tonnes from bi-polar membrane cell (1991) for Tiwest Joint Venture. bulletKemerton Western Australia, producing 17 000 tonnes from bi-polar membrane cell (1988) for SCM. Elite Chemicals (a subsidiary of Ionics Inc of the US) at Brisbane Queensland (since 1986) producing 7000 tonnes of chlorine using ionic membrane cell. For sodium hypochlorite and 33 per cent hydrochloric acid.

Nufarm Limited at Laverton near Melbourne, Victoria. About 6 000 tonnes of chlorine using monopolar membrane (1989) to produce 2,4-D and trifluralin herbicides.

Kiwi Brands near Melbourne Victoria producing 1500 tonnes of chlorine from ionics membrane cell (1987) to produce sodium hypochlorite.

CSBP, subsidiary of Wesfarmers in Kwinana Western Australia, 5500 tonnes of chlorine from membrane cell to produce chlorine, sodium hypochlorite and hydrochloric acid.

(A chloralkali cell owned by Orica is mothballed at Osborne South Australia. With closure of paper mill at Burnie Tasmania, a 8 000 tonne plant was closed).

1. Chloralkali ventures in WA

See also extract report

The WA government has expectations for a petrochemical venture costing around A$2bn by year 2003 at the source of NW gas in the north west either at Hearson Cove on the Burrup Peninsula, or nearer Karratha at the Maitland Industrial Estate. Some 500 000 tpa of ethane would be used with salt supplied from Dampier Salt 20 km away. Caustic soda, EDC/VCM and caustic soda would be produced.

In July 2001, one of the venturers announced its withdrawal. Details

A restraint is the cost and availability of ethane. Domestic gas supplies (Dampier Bunbury and Dampier Kalgoorlie) jointly could by ACTED estimates (in 1999), provide for 500 000 tpa of ethane with near 100 per cent extraction which is more costly than extracting say two-thirds. (Extracting above 65 per cent requires not only lower temperatures but also removal of carbon dioxide gas). With contractually bound restraints, ethane would probably not be available from current exports but from future gas developments and providing these contained adequate ethane. Wesfarmers and Orica have both expressed interest in ammonia (and ammonium nitrate and urea) plants. The required methane would release some needed ethane.

In June 1998, Dow Chemical and Shell were identified as the preferred builder of A$2bn venture to commence construction in year 200 and production in 2003. Other companies that were included in the Government's shortlist were BP, Dow with Shell, Hanwha, Orica and Krupp Uhde. Hanwha Corp was interested to take a share in BP Chemicals' planned ethylene cracker project with its proposed chloralkali and ethylene dichloride project. Hanwha proposed a 500 000 tonne per year of caustic soda and 620,000 tonne per year of EDC. BP proposed a 450,000 tonne/year cracker. Hanwha was also interested in Wesfarmers participation in an ammonia project.

Shell and Dow will have the right to present a formal development proposal for the project which remains subject to a feasibility study. The companies are seeking government assistance by way of infrastructure funding and amounts of A$300m have been discussed.

The project points to the need for scale. Adequate scale for chloralkali production, say 500 000 tpa of caustic would require the production of some 700 000 tonnes of EDC that requires 200 000 tpa of ethylene which is below world scale. Hence the involvement of Shell to produce other ethylene products. The problem of scale requires the production of 600 000 to 800 000 tonne of ethylene. It would make economic sense for other ethylene derived products to be produced such as polyethylene resin, acetic acid and acrylonitrile.

In April 1999 Dow/Shell announced that the Pilbara Petchem Project hinged on expansion at NW Shelf (export probably not until 2003-2005) and domestic from BHP's HBI project. (Ie. not enough ethane available from domestic supply so limiting its scale). Shell later threatened to withdraw for want of enough government subsidy.

In June 1999 the project took a tentative step forward with the jv partners Shell Chemicals and Dow forecasting a modest return on the $2 billion investment, but still only 66% of the required level; the jv is now proposing capacity increases - ethylene from 450 kt to 625 kt/year, as well as to pencil in an additional $2 billion for new, associated plants, in particular mono ethylene glycol (550 kt/year), chlorine/caustic soda (825 kt/year), and ethylene dichloride (1 Mt/year). 

In 2001, the project has been scaled up to 800 000 tpa capacity of ethylene, 825 000 tpa caustic and 825 000 tpa of EDC. Surplus ethylene to be overcome by producing MEG (glycol). The project is being helped by announced LNG expansion.

in June 2001, the memorandum of understanding with the Government of Western Australia expired . Dow Chemical blamed its failure on the failure of other big gas-intensive projects to get off the ground to provide the ethane.A Shell spokesman said that while the company would not pursue a petrochemical project, Australia remained on its list of potential sites for a $4 billion gas to liquids project.

Mineral and Petroleum Resources Department acting director-general Mr Jim Limerick denied the Dow-Shell decision was a blow to WA. ``There are whole lot of other companies that have come along in the meantime that want to utilise gas up there," he said.


Our estimates of competitiveness of the chloralkali component of the venture suggests it to be marginal when freight and construction and infrastructure costs are included. ACTED estimates the net advantage at around US$20 per ECU or US$10 per tonne of caustic and chlorine (say 10 per cent by value). Not only marginal, that margin is effectively eroded for potential investors to negative values when allowance is made for the fact that Australia does not offer tax holidays unlike some competitive Asian nations. The scale and product mix suggests the project could be a "bargaining chip" to obtain an investment incentive from an Asian country.

The question of why ethane containing LNG continues to be exported, with specifications tied up in supply contracts, remains. We argue that the government failed to recognise the important role it had right up until around 1990. 

1988 venture

It is worth noting that the state has had a shaky start with a failed petrochemical venture (PICL, to produce 250 000 tpa caustic soda, 350 000 tpa of VCM and EDC). The project was to be located near Perth (Kwinana) at the end of the north west pipeline and would be using gas with a A$1.20/Gj pipeline overhead charge (ie. 70 per cent cost impost on today's deregulated gas price!). About the time of PICL, there had been an evaluation for an ammonia and urea plant by Wesfarmers but this too failed to progress though a smaller ammonia project is being built.

The project would have had to absorb a gas tariff cost of around $15 million per year! (Based on 3.2 MWh of power per ECU [an ECU is 1.0 tonne of chlorine plus 1.1 tonne of caustic soda]; and 10gigajoules per 1MWh plus gas required for the C2 part of the VCM/EDC. Add to that cost the penalty of operating at well below competitive world scale and one wonders why the government supported this project that cost it A$400million in backing this dinosaur.

Six years later, an LNG plant was established that extracts LPG but not ethane. There is inadequate ethane available to support a petrochemical project.  (See also Opinions).

One analyst has speculated about a chloralkali plant located in Victoria. More ethane can be drawn from Bass Strait gas.


See more information under caustic soda.

Hydrochloric acid

Hydrochloric acid (HCl) is an important industrial acid in Western Australia used in a broad range of resource developing industries. It is traditionally produced by reacting sodium chloride (common salt) with sulfuric acid and produced by chloralkali plants where there is surplus chlorine or if favoured by the economics of the region.

The chlorine used in the titanium dioxide pigment plants results in nearly all being converted to hydrochloric acid. About 40 000 tonnes of hydrochloric acid is produced by the two plants at a concentration of about 30 per cent (commercial grade is 33 per cent). Though of high concentration, the acid contains inorganic impurities such as silicates which render it unsuitable for many applications. Some hydrochloric acid is used but most is neutralised with lime to produce about 10 000 tonnes of calcium chloride at each plant that is either washed to sea as a non-polluting dilute effluent (by Tiwest), or stored in settling tanks pending disposal (by SCM).

Nufarm Coogee and CSBP both manufacture hydrochloric acid at their chloralkali plants by direct synthesis from hydrogen and chlorine, (previously producing it by the chemical reaction of sodium chloride with sulfuric acid). Local demand and production patterns favour this inherently more expensive route.


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Chemlink Pty Ltd ACN 007 034 022. Publications 1997.
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