Suntech Power (NYSE: STP) said Tuesday it plans to raise between $425 million and $500 million by selling convertible senior notes to institutional investors in a private offering.

The solar-panel manufacturer said it will spend approximately $300 million of the cash to buy supplies, expand its production capacity and commercialize new technology. It plans to use the rest for "general corporate purposes," as well as potential investments and acquisitions in complementary businesses and technologies.

The news came a day after the Washington Post reported that Chinese solar-silicon companies were dumping toxic waste. Luoyang Zhonggui High-Technology Co., which was cited by the Post as a prime example, sells silicon to Suntech Power, as well as to LDK Solar and Canadian Solar, according to Piper Jaffray.

After falling 7 percent Monday and 5.71 percent Tuesday to close at $30.24 per share, Suntech stock was up 6.61 percent to 32.24 by midmorning Wednesday.

By comparison, Canadian Solar (NSDQ: CSIQ) grew 7.1 percent to close at $18.64 per share Tuesday after falling 15 percent to close at $17.41 per share Monday. The stock is 40.7 percent off its 52-week peak of $31.44 per share, set Dec. 26, but almost triple its 52-week low of $6.50 per share, set Aug. 16.

Also, LDK (NYSE: LDK) rose 3.2 percent Tuesday to close at $22.19 per share after falling 4.5 percent Monday to close at $21.50 (see LDK Sinks on Silicon, Economic Fears).

In a Web update about a silicon plant it is building, the Chinese solar-wafer company seemed to respond to the concerns about toxic waste from silicon production:

"LDK’s [sic] has a vested interest to build and operate a safe and environmentally friendly polysilicon plant. We are implementing the latest proven technology from the west. … Once completed our plant will have a totally closed loop system where the majority of the potential waste (STC) will be recycled."

Overall, clean-energy stocks were up Tuesday, with the WilderHill Clean Energy Index rising 4.8 percent to close at 202.46 points.