WASHINGTON - The US government on Thursday launched an antidumping (AD) investigation against imports of silica bricks and shapes from China.

The products covered by the investigation are bricks and shapes, regardless of size, containing at least 90 percent silica, also known as silicon dioxide, said the US Commerce Department in a statement, alleging that those products were sold at less than fair value in the US market with dumping margins from 118.47 percent to 290.12 percent.

Silica bricks and shapes are a type of refractory bricks used to line furnace roofs. In 2011, imports of silica bricks and shapes from China were at an estimated 43.2 million US dollars, according to the Commerce Department.

The US International Trade Commission (ITC) was scheduled to make its preliminary injury determination on or before December 31, 2012.

If the ITC determines that there is a reasonable indication that imports of silica bricks and shapes from China are materially injuring to or threatening the domestic industry, the probes will continue. Then the Commerce Department will be scheduled to make its preliminary determinations in April 2013.

This is the latest US trade protection move against China this year. As of November 6, 2012, Commerce had maintained 117 AD and countervailing duty (CVD) orders on imports of a wide range of Chinese products, including consumer goods, steel products, agricultural products, seafood, and chemicals.

As the US economy is undergoing a slow recovery, protectionism practices by the world's largest economy are on the rise. The Chinese Ministry of Commerce has repeatedly urged Washington to abide by its commitment against protectionism and help maintain a free, open and just international trade environment.