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Environment industries archive

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Key departmental publications, e.g. annual reports, budget papers and program guidelines are available in our online archive.

Much of the material listed on these archived web pages has been superseded, or served a particular purpose at a particular time. It may contain references to activities or policies that have no current application. Many archived documents may link to web pages that have moved or no longer exist, or may refer to other documents that are no longer available.

Industrial Galvanisers Corporation
Cleaner Production - Greater Process Control in Hot Dip Galvanising

This case study is no longer current with respect to the Company's business activities and operations and was not updated in the review of 2001, but is retained for informational, educational and historical purposes.

Industrial Galvanisers Corporation is saving $100,000 per annum in waste fluid disposal costs through greater process control of their hot dip galvanising. The new process, developed by the company’s R&D team, is a continuous electrolytical preflux treatment. It has also delivered quality improvements and other savings by allowing better monitoring of, and hence improvements in, plant management. The reduction in waste effluent and fume levels is a major environmental breakthrough for this industry.

The process

The hot-dip galvanising process uses hydrochloric acid (pickling acid) to clean steel before it is immersed in molten zinc. The waste liquids and fumes generated by the galvanising process have earned the galvanising industry a reputation as environmentally unfriendly. Disposal of the waste fluid generated by the overflow rinse tank - consisting of iron chloride, zinc chloride and unused hydrochloric acid - is the major environmental challenge facing the galvanising industry worldwide.

Cleaner production initiatives

Industrial Galvanisers Corporation Pty Ltd began research into ways of reducing waste fluids from the galvanising process in 1991. Industrial Galvanisers' research and development team saw this as a means of reducing both company costs and improving environmental performance.

Their work led to the continuous electrical preflux treatment (CEPT), which controls the iron levels in zinc ammonium chloride preflux solutions. The process is based on an electrolytic reactor, in which iron in the preflux solution is oxidised to an iron hydroxide precipitate. The dissolved iron had previously rendered the solution ineffective, but its removal as a precipitate means that the solution can continue to be used. This, in turn, reduces the waste disposal requirement by up to 50%.

Advantages of the process

The benefits are:

Following implementation of the CEPT system, one plant has reduced by 50% the amount of contaminated fluids requiring disposal. This, in turn, reduced the load on the environment and cut the plant's annual waste fluid disposal cost of A$200,000 in half.

The introduction of CEPT technology also allowed more detailed monitoring of the condition of the preflux bath, and of the performance of the metal preparation line. CEPT has become a useful management tool, allowing product quality to be improved, and delivering additional savings from improvements in overall plant management.

Cleaner production incentives

The financial benefits of reducing a key production cost, and a desire to help change the image of galvanising as an environmentally unfriendly industry, were the key imperatives for Industrial Galvanisers. The philosophy of cleaner production enabled the two objectives to be combined. 

Date of implementation: 1996.
Case study prepared: 1997
Last reviewed: June 2001.