Chapter 26: Bioleaching of Copper
"I think what he said makes a lot of sense," Qin Jianshe said with a smile.
He firmly took Li Tang's side, trusting his judgment without reservation.
Rationally speaking, he knew that the low-grade ore in front of them likely held little value under current conditions—just as the experts had said.
"Technological progress isn't that easy," Professor Sun Yiquan sighed, reacting to Li Tang's earlier comments.
Others chuckled in agreement.
It wasn't meant to mock Li Tang—they simply thought the young man's ideas were idealistic.
Lu Kanqing assumed Li Tang didn't understand smelting, so he explained, "To process copper ore, it must go through several stages—grinding, classification, flotation using special reagents, and drying. For the same amount of copper, low-grade ore requires far more energy and chemical reagents than high-grade ore! Naturally, the cost is multiple times higher!"
"I understand," Li Tang replied. "That's exactly what I meant by 'fixed thinking.'"
He wasn't dismissing their logic—he simply saw a broader perspective.
"Because there's already a pyrometallurgical refinery in place, everyone has been focusing on supporting the existing smelting infrastructure. No one's considered the possibility of hydrometallurgy—specifically, bioleaching."
"Bioleaching?" some experts echoed in confusion.
"Do you even know what bioleaching is?"
"Hydrometallurgy does cost significantly less than pyrometallurgy," one expert noted. "As you mentioned earlier, traditional smelting costs more than 12,000 yuan per ton internationally, while hydrometallurgy costs less than 8,000 yuan. Yet it accounts for less than 10% of copper production worldwide—both in China and abroad."
"If hydrometallurgy is cheaper, why don't more people use it? Are they all fools? Of course not. Though the process is similar in theory, the results differ greatly!"
"Hydrometallurgy struggles to handle impurities. Pyrometallurgy can produce copper that meets national standards. But hydrometallurgy often can't remove enough contaminants, and the copper produced frequently doesn't meet the required grade."
"Hydrometallurgy isn't new to China—we've had it for centuries. If it were really that good, why have all the major refineries discarded it?"
The discussion quickly turned into a wave of objections, overwhelming and overlapping.
But Li Tang stood firm—like a rock resisting the tide.
The experts weren't wrong. Hydrometallurgy in China did have ancient roots, even dating back a thousand years.
The "History of the Song Dynasty – Records of Finance" described an old method called dan tong fa, which used iron sheets immersed in copper sulfate solution. The process extracted copper through simple redox reactions. Roughly two and a quarter pounds of iron would yield one pound of copper.
Li Tang understood their perspective.
But once again, they had missed the real point.
"There are many types of hydrometallurgy. What I'm talking about is bioleaching," he finally clarified.
"Bioleaching?"
Now the room went silent.
This was unfamiliar territory, especially in China. Bioleaching was still considered cutting-edge—and rare.
Even within the already niche domain of hydrometallurgy, bioleaching was a fresh frontier.
Everyone has their area of expertise. Experts often specialize narrowly. And in this case, many of them simply didn't know enough about it to comment.
"Professor Sun, you know a lot about copper mines. Are you familiar with this method?" someone asked.
"It's not a mainstream technique," Sun replied cautiously.
"Under what conditions would this method be appropriate?"
"Which mines in China use it?"
"I've only heard it can process low-grade ore. Some foreign mines use it for the margins of ore bodies."
"I think it was first introduced about thirty years ago, at a mine in the U.S. called Blue Pool—or something like that. It's still a new technology, but it's developed rapidly over the past decade or so."
What the crowd knew was vague—mostly hearsay. No one offered technical specifics.
Hearing this, Zhao Hepu fell deep into thought.
He had almost forgotten that he had once investigated bioleaching in person.
"We actually have a major copper company in our province that's running trials on this," he said, "and it's shown promising results for leaching brass ore."
"If that's the case, why haven't we done similar trials here at Demen?" Li Tang asked, surprised. He hadn't expected Zhao to have any direct experience with bioleaching.
And now that he mentioned it, Li Tang suddenly remembered—China's first major bioleaching copper facility was in Jiujiang Province!
"Which company did you visit?" he asked.
"Jiujiang Copper," Zhao replied. "It was about two years ago. Back in 1994, they started experimenting under the national Ninth Five-Year Plan's tech initiative. By 1997, they built a pilot plant with a capacity of 2,000 tons per year."
"That mine has nearly the same lithology as Demen. If their bioleaching trials were effective, then it should work here too," Li Tang said, smiling.
"I visited the site, and to be honest, the results weren't all that great. There were some breakthroughs, but the technology was far from mature," Zhao replied candidly.
Lu Kanqing added his thoughts as well. "We heard the leaching cycle was around 800 days, with a recovery rate of 40 to 60 percent. So only about half of the copper could be extracted—and the process took more than two years. That's just too slow."
"No wonder it hasn't been widely adopted yet," Li Tang nodded in understanding.
"More importantly," Zhao continued, "at the time, we weren't even thinking about reclaiming tailings. We were focused on finding new ore bodies or extending the mine's life by other means. Jiujiang Copper developed bioleaching mainly because they had nearly a billion tons of waste ore to deal with. Their problem was very different from ours. We just didn't see the value then."
"But," Zhao added, glancing at the listening experts, "bioleaching may not be ideal for high-grade ores—but it's very effective for low-grade ones!"
He turned to Li Tang and smiled with clear appreciation. "If you hadn't brought it up today, I would've completely forgotten about bioleaching."
Qin Jianshe knew a bit about exploration—but copper smelting was another matter entirely. The conversation had left him a bit lost.
Still, he was once again impressed by Li Tang's sharp thinking and broad vision.
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