Sun Metals has always recognised the significant value of our secondary products, and the principle of maximising resource efficiency and minimising waste has been an integral component of Sun Metals’ operating philosophy from the design of the original refinery.

Sulphuric Acid

A key secondary product of the zinc refining process is sulphuric acid.  Sun Metals zinc refinery produces approximately 450,000 tonnes per annum of 98% sulphuric acid which is sold to both domestic and international customers, primarily for use in fertilizer manufacture and mining operations. Other industries which utilise sulphuric acid in their processes include:

• chemical manufacture;
• steel production; and
• paper manufacturing. 

Sun Metals has purpose built sulphuric acid storage tanks at the refinery site and facilities to load both specialised train wagons and tanker trucks for delivery of sulphuric acid to our domestic customers.  Sun Metals also has sulphuric acid storage tanks located at the Port of Townsville to provide additional storage capacity and to enable export of acid by ship to our international customers.

Agricultural Grade Gypsum

A high purity gypsum product is produced within the leaching and purification stage of the zinc refining process. The gypsum, also called ‘SZP Cake’, is suitable for use as a soil conditioner in agricultural industries. Sun Metals produces approximately 10,000 tonnes per annum of agricultural grade gypsum which is sold for use in the nearby Burdekin agricultural region.

Industrial Grade Gypsum

Approximately 30,000 tonnes per annum of an industrial grade gypsum is produced within the zinc refining process. The industrial gypsum is produced at several locations within the process including the purification plant, water treatment plant and cooling towers. The industrial gypsum has higher levels of impurities than the agricultural gypsum which make it unsuitable for agricultural use. The industrial gypsum is however suitable for use as a calcium source in cement manufacture.

Iron Oxide

Approximately 60,000 tonnes per annum of iron oxide, containing approximately 50% iron, is produced by the Sun Metals zinc refining process, within the ferric oxide plant.  The iron oxide is suitable for use in a range of industries including:

• Cement manufacture;
• Steel manufacture;
• Civil construction (such as roads); and
• Paint and pigment manufacture.

Lead Sulphate

A metallurgical intermediate lead sulphate product is manufactured within the leaching and purification part of the zinc refining process. The lead sulphate contains economically valuable quantities of lead and silver. Sun Metals produces approximately 80,000 tonnes per annum of lead sulphate which is exported through the Port of Townsville to international customers who further process the product to recover the lead and silver content.

Copper Cement

Another metallurgical intermediate product, copper cement, is manufactured within the ferric oxide stage of the zinc refining process. The copper cement contains economically valuable quantities of copper. Sun Metals produces approximately 10,000 tonnes per annum of copper cement which is exported via the Port of Townsville to international customers who further process the product to recover the copper content.

Manganese Dioxide

Manganese is a commercially important commodity, predominantly used in the manufacture of metallurgical alloys, but also used in alkaline battery manufacture Manganese Dioxide is formed within the electrolysis stage of the Sun Metals zinc refining process. 

Sun Metals produces approximately 3,000 tonnes per annum of manganese dioxide which is exported via the Port of Townsville to international customers.