Horne acid plant nears completion

The plant, which is designed to reduce smelter emissions by half, should be up and running by the first of October and be in full operation by the end of the year, The Northern Miner learned during a recent tour.

Quebec law requires Noranda Minerals, the operator, to cut smelter emissions (based on a 1980 base figure of 552,000 tonnes sulphur dioxide) by 50% by 1990.

Government regulations at present require no further reductions, but Noranda, working on its own, is hoping to be able to cut emissions by 70% by 1992 or 1993, said Derek Pannell, Horne general manager. To achieve the increased reduction, an additional $16- million expenditure is planned for a concentrate injection program.

Pannell said the company has been successful this year in reducing emissions by 35% through selective processing of low sulphur- bearing feed.

Cost to build the acid plant is estimated to be $160 million. Noranda obtained loans totalling $83 million from the federal and Quebec governments to help pay for the facility.

The Horne smelter, built by Noranda in 1927 to service a now depleted copper mine, is reported to be the second-largest source of sulphur dioxide emissions (a major cause of acid rain) in North America. The largest source is Inco Ltd.’s nickel-smelting operation in the Sudbury area of northern Ontario.

The smelter features both a conventional and a continuous smelting process. The former involves the use of a normal reverberatory furnace and the latter a reactor, a technological advance introduced by Noranda in 1973 which is built in the shape of a horizontal cylinder.

During the smelting process, hot gases are produced containing particulate metal oxides and sulphates, nitrogen and residual oxygen, moisture and sulphur oxides. The gases are treated for the removal of the particulates; the new acid plant will recover sulphur as sulphuric acid.

When the acid plant is ready, plans call for the conventional process to be bypassed and most of the feed to be sent to the reactor. The resultant gases will then be treated by the acid plant. The balance of the smelter feed will be sent directly to the converter for processing.

To be marketed by Noranda Sales, the acid will be made available in a number of qualities — 93%, 96% and 98%. Including the 350,000-400,000 tonnes sulphuric acid to be produced by the Horne plant in 1990, Noranda will have about one million tonnes of the material for sale next year from its various Quebec operations.

Sulphuric acid has application in the manufacture of explosives, alcohols, soft drinks, detergents and fertilizers. The Horne smelter is currently running at capacity, treating concentrate from both Canadian and overse as sources, Pannell said. Scrap or secondary material accounts for about 15% of the feed but about one-half of the smelter’s revenue, he said.

In Sudbury, Inco announced plans at the end of 1988 for a 60% reduction in sulphur dioxide emissions from current levels. The company will invest about $414 million on the project over five years.

]]>