Shanghai Baosteel Group Corp, the world's sixth-largest steelmaker, has found a way to convert its once useless steelmaking slag into fertilizer.

Baosteel has succeeded in laboratory experiments on transferring liquefied steelmaking slag into a compound containing potassium, a substitute for normal potassium fertilizer, the company's research institute announced.

"The technology helps Baosteel cut solid waste exposure," Ren Yusen, a researcher involved in the project told Shanghai Daily. "As a steelmaker, we are not keen on selling fertilizer in the long run but exploring a wider use of the technology."

The effects of the new fertilizer can last two years, so farmers spend less time fertilizing their fields, he added.

The new compound also doesn't pollute the soil it is used on, Ren said.

Baosteel has already applied for a patent for the technology and is awaiting its approval.

The institute has tested the slag fertilizer on potatoes, which need potassium to grow, and it increased output by 15 percent compared with potatoes grown in normal soil. The lab experiment lasted about 10 months, Ren said.

Baosteel is now cooperating with the China Academy of Agriculture Science to test the technology on wheat, corn and rice. They will conduct a two-year test on a large swathe of farmland to see how well the fertilizer works with other crops.

Baosteel started researching the project in 2000 to see how steelmakers outside the country use their old slag, Ren said.

Companies in Germany, the United States and Japan also turn slag into fertilizer.

The component of steelmaking slag is similar to that of the soil, which will help crops grow.

About 70 kilograms of steelmaking slag will be produced from smelting a ton of molten liquid steel.

Baosteel made 21.38 million tons of steel in 2004 as China's first steel company whose output surpasses 20 million tons.

(Shanghai Daily April 19, 2005)