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Rockwood closes on $635M sale of unit to Altana

PRINCETON, N.J. (AP) -- Specialty chemicals company Rockwood Holdings Inc. has completed the $635 million sale of its clay-based additives business to Germany's Altana Group.

Rockwood, based in Princeton, N.J., announced the deal in July. As a unit of Rockwood, the clay-based additives business is relatively small. It had sales of $191.4 million in 2012, or about 5 percent of Rockwood's annual revenue.

The additives are used to modify viscosity, thickness and flow characteristics, and keep solids in suspension in a variety of products. They are used in industrial and architectural coatings, oil and gas drilling fluids, consumer and household care products, and inks, paper and composites.

Rockwood said Wednesday that it will receive more than $600 million in proceeds from the sale.