Atlantic Copper ups smelter output 10-15 pct

* Huelva anode output up to 300,000 T/yr

* Company says selling all sulphuric acid output

MADRID, Oct 2 (Reuters) - Spain's Atlantic Copper, part of Freeport McMoRan Copper & Gold Inc. (FCX.N), has raised production at its Huelva smelter by 10-15 percent since the beginning of August, it said on Friday.

A company official said the increase would raise the smelter's output to 300,000 tonnes per year of copper anodes and was due to improvements in efficiency and using more oxygen in the furnace.

Anodes are basic copper blocks that are later refined.

Encouraged by higher prices, some metal producers have started to reverse earlier cutbacks and project delays, prompted around mid-2008 by plunging demand.

The official added that Atlantic Copper was selling all the sulphuric acid produced by the smelter, despite a leading client closing a plant in the southwestern port of Huelva.

"We are placing all of our acid," the official said.

Fertiliser maker Fertiberia used to buy 30 percent of the 1 million tonnes of sulphuric acid -- a by-product of copper smelting -- produced annually in Huelva.

Spanish farmers say they have used a lot less fertiliser this year because a collapse in grain prices GRAES01 has forced them to cut back on production costs.

The official added that Atlantic had invested 20 million euros ($29 million) in the past two years in extending port facilities to handle acid.

Clients included parent company Freeport's installations in the Americas, a net importer of sulphuric acid produced in Europe and Asia.

Last year, Atlantic Copper said it sold about 300,000 tonnes of sulphuric acid a year on the spot market, which it hoped to raise to 500,000 a year in 2009 and 2010. [ID:nLE236871]

Some copper and zinc smelters were forced to cut their output earlier this year because they ran out of space to store hazardous sulphuric acid in the face of poor demand for the by-product.

However, some plants have returned to full production due to improvements in the sulphuric acid market. For more facts on idled mines and metal plants which have restarted, please click on [ID:nLL34186] (Reporting by Martin Roberts, editing by Anthony Barker)