China imported 676,299 tonnes of refined zinc last year, compared with 424,440 tonnes in 2016, official customs data showed. Supply of refined zinc and zinc concentrates in China’s domestic market were both tight in 2017 due to a slight decrease in domestic production and a pick-up in demand from downstream consumers, which drove market participants to step up their procurement of these materials from overseas sources, Metal Bulletin understands. Under the tightened market conditions the zinc import arbitrage window opened twice last year, which is a rare occurrence – once from mid-May to the end of June and again from the middle of August before narrowing in October.