BEIJING (Reuters) – Zhang Shiping, who oversaw the rise of China Hongqiao Group into the world’s biggest aluminium producer, died on Thursday at the age of 73, the company said.

Zhang, who in 1994 took over the predecessor company to Hongqiao, a textiles firm in eastern China’s Shandong province, branched out into aluminium in 2002.

As chairman of Hongqiao, he turned the company into an aluminium giant that produced more metal than state-run rival Aluminum Corp of China Ltd, often known as Chalco. In 2015, Hongqiao overtook Russia’s United Company Rusal as the world’s top aluminium producer.

It currently has just under 6.5 million tonnes of smelting capacity, but has found further expansion in China restricted in recent years due to supply-side reform and an environmental protection campaign.

Zhang made an “invaluable contribution to the success of the group during his tenure”, Hongqiao said in a statement to the Hong Kong stock exchange late on Thursday. It did not give a cause of death.

Based in the city of Binzhou, Hongqiao was listed in Hong Kong in 2011, although Zhang still controlled around 70% of its shares, according to Refinitiv Eikon data. Forbes estimates Zhang’s net worth at $4.7 billion, putting him in 484th place in its Billionaires 2019 list.

“(Hongqiao) will convene a board meeting to elect the chairman of the board as soon as possible,” the statement added. Zhang’s son, Zhang Bo, serves as chief executive officer.

Zhang was also a non-executive director of Weiqiao Textile Co Ltd.

The websites of Hongqiao and Weiqiao Textile were reduced to black and white on Friday, the traditional colours of mourning in China.