Alcoa reported lower third-quarter earnings Thursday due to falling aluminum prices as it trimmed its outlook for key Chinese businesses.

Earnings for the quarter ending September 30 were $44 million, down 70.4 percent from the year-ago period. Revenues fell 10.7 percent to $5.57 billion.

The results translated into seven cents per share, compared with the analyst projection of 14 cents per share.

Alcoa faced "economic headwinds and significant volatility in some of our markets" during the quarter, said chief executive Klaus Kleinfeld.

Much of the year-over-year earnings decline was due to special charges totaling $65 million, partly in restructuring costs and the shutting of less-profitable assets.

Lower aluminum prices were also a factor. Aluminum prices were down 25 percent from last year to $1,901 a metric ton, amid a broader pullback in commodities due in part to slower growth in China.

Alcoa cut its forecast of growth in sales to the Chinese automotive sector this year to 1-2 percent, from the prior forecast for 5-8 percent growth.

It also reduced its forecasts for commercial building and construction sales in China, while keeping sales growth to China's packaging industry unchanged at 8-12 percent.

Alcoa kept its 2015 estimate for global aerospace business growth at 8-9 percent.

Alcoa announced last week plans to split itself into two companies, one focused on upstream mining and smelting and the other on manufacturing aluminum products to supply industries including aerospace and auto manufacturing.

Shares of Alcoa fell 4.7 percent to $10.49 in after-hours trade.