ABB robots enhance work at zinc smelter

ABB’S robots have been used in Nyrstar’s zinc smelting facility in Tasmania to eliminate the dirtiest and riskiest jobs in the metal making plant and improve the quality of the end product.

Zinc smelting has traditionally involved hard, dirty and risky jobs. Until four ABB industrial robots were installed in 2008, 16 men had to sit beside the 600 degrees Celsius molten metal to manually skim off the “dross”. This has now been automated, and as a result, ingots are cleaner, smoother and more accurately weighed.

The robotic cells were installed on four lines producing 25kg zinc and 9kg zinc alloy ingots. The metal is used for galvanising, alloying, die-casting, in battery casings, car panels, and zinc cream.

During ingot casting, molten metal from the furnace is pumped into pouring bowls on the lines. Prior to the robots being installed, a pneumatically controlled system poured the metal into each mould on a conveyor. Donning a full set of personal protection equipment, operators then had to rake off the waste “dross”. The process was not precise, resulting in quite a bit of reject-weight zinc.

The robotic cells installed included an automated servo-control system for the pouring bowl, an ABB ARB4400 robot, a vibratory conveyor for the dross, and level-checking lasers. Altogether, the project cost $3m, and each robot was installed over four days.

As a result of the robots, there has been a 60% decline in reject-weight ingots, a reduction in deformation-causing ‘flash’ metal, and an increased smoothness and consistency to the product.