The United States has announced new tariffs and price floors on polysilicon and related products, targeting China’s dominance in key materials used in solar panels and semiconductor manufacturing.In a proclamation signed on Thursday, US President Donald Trump imposed a 15 per cent tariff, which will take effect after 120 days, and established a series of price floors to protect domestic manufacturers and curb imports of China-sourced materials.“We’re setting prices so that the Chinese can’t...