Paper mills in China have succeeded in turning out high-quality paper with ultra-fine ore powder, which is being used to serve as a substitute for pulp wood.
Southwestern Yunnan Province, the first region in China to experiment with the new source of material in paper-making, has turned out thousands of tons of paper with wollastonite as the base material. And paper mills in western Shaanxi and Sichuan provinces and Shandong Province in east China have also followed suit.
With advanced grinding technology, wollastonite could be reduced to an ultra-fine power dust to serve as pulp for making paper of all sorts ranging from ordinary writing paper to art paper.
There is no need to refit the paper-manufacturing machinery or alter techniques, said Zhong Guangrong, a senior engineer of the Institute of Non-Ferrous Metal Application in the province on Friday.
Shi Yubei, general manager of the Yunnan Ultra-Fine New Materials Co. Ltd., estimated that the consumption of one ton of wollastonite would save 3.6 cubic meters of timber and discharge less waste water from paper mills accordingly, he added.
China was the second largest paper producer and consumer in the world, and a major paper importer in 2001. Application of the technology was of great importance, said He Ying, an official with the Yunnan Provincial Paper-Making Society.
China abounds in wollastonite with proven reserves of nearly 370 million tons, ranking the second in the world after the United States. Wollastonite is found in 14 provinces and autonomous regions in China. Yunnan Province, has verified reserves of 53.63 million tons, making up 28 percent of the national total.
Since the Chinese government banned timber felling on the upper reaches of the Yangtze River, the price of paper wood has soared, driving some paper mills into dilemma or bankruptcy. The use of wollastonite has opened a new "window of hope" for the industry.
Paper making required a combination of long and short fibers, said He Ying. The long fibers served as the "frame" while the shorter ones were the "cement and sand".
A mixture of pulp wood and wollastonite would complement each other and make up each other's deficiencies. As wollastonite powder is in the needle-like shape, it has stronger adhesive force than any other materials.
Paper manufactured with wollastonite raises paper opacity and improves its quality, but without producing any static electricity.
Compared with pulp wood, the price for making each ton of wollastonite paper dropped by up to 300 yuan (about US$36).
China produces 30 million tons of paper annually. With rising production costs, there would be a bigger demand for wollastonite in paper-making, General Manager Shi Yubei said.
(Xinhua News Agency June 13, 2003)
