Rare earth colorants to start production

Nontoxic colorant from rare earths is expected to be put into full production in the current year in Baotou, the biggest city in the Inner Mongolia autonomous region, following a decision by the local government to upgrade the rare earths industry to value-added processes against previously mining the raw materials.

"Due to its perfect coloring and nontoxic properties the coloring agent, mainly for plastics and leathers, can replace most existing dyes in the market," said Zhang Hongjie, inventor of the colorant and member of the Chinese Academy of Sciences.

There are currently two kinds of coloring agent in the Chinese market: organic compounds releasing toxic gases with high temperatures and inorganic compounds containing heavy metal elements like lead and cadmium.

The research findings were very important, because China's plastic output is the second biggest in the world and plastic products have been criticized a great deal by Western countries for containing harmful materials, Zhang said.

The move to produce the colorant follows plans by private company Century Zhongtian (Beijing) Investment Co Ltd and the Baotou Rare Earth Research Center to form Zhongke Century Technology Co Ltd. That was in the wake of the research center successfully manufacturing the nontoxic tolerant in November.

Baotou-based Zhongke Century, which aims to be the world's biggest rare earth colorant research center, plans to invest 1 billion yuan ($14.5 million) and build two production lines with respective annual output of 50 metric tons and 100 tons, worth a combined 10 billion yuan each year.

"The preparation work at early stage of the project is under way," said Geng Biao, general manager of the investment company.

"Currently site selection and fundraising is taking place," Geng added.

Estimates are that rare earths reserves in Baotou account for 83 percent of the total in China and 30 percent of world reserves.

The local government is promoting the upgrade of its rare earths industry from previously exploiting the raw materials, to developing comprehensive processing technologies with higher added value.

Around 5.9 million yuan in special funds were allocated by the Office of Science and Technology in Inner Mongolia, to financially support the construction of a production demonstration line at the Baotou Rare Earth Research Center.

"Technologies for producing colorant from rare earths and sulfides are one of the most import improvements in developing rare earth in the downstream chain," said Chi Jianyi, director of the Baotou Rare Earth Research Center.

The technology was listed in a list of prescribed alternatives to toxic and harmful materials, issued by Ministry of Science and Technology, the Ministry of Industry and Information Technology and the Ministry of Environmental Protection.

Widely used in the fields of plastics, paints, inks and leathers, the coloring agent has huge potential in market demand, said Chi.

"Without toxicity, the coloring agent we produce is totally environmentally friendly and can even be used in lipstick manufacturing."

Based on three patented technologies, the green dyestuff is a synthetic product of rare earth elements including lanthanum, cerium and sulfides.

Research into the rare earth colorant began in 2003, when scientists from the Chinese Academy of Sciences worked with experts from Russia, who used traditional methods to produce the rare earth agent.

"The traditional method is not only sophisticated but also very costly, so it can not be used in large-scale production," said colorant inventor Zhang Hongjie.

The start of production of the colorant will be the result of more than 10 years of successful research by the laboratory. Zhang said scientists had invented a totally new method of producing colorant from rare earths and sulfides which was simple and practical, without using hydrogen sulfides and other toxic materials.

The patented technology will also see large-scale production of the staining material.

At the moment studies on rare earth sulfide synthetics, especially on their application, remain at the early stage.

Contact the writers at mengfanbin@chinadaily.com.cn and yuanhui@chinadaily.com.cn