coal by-product

例句：

1. 1. The company's main product is coal by-products, which are used in various industrial processes.
   该公司的主要产品是煤炭副产品，用于各种工业过程。
2. 2. Coal by-products can be used as a source of energy and contribute to the reduction of greenhouse gas emissions.
   煤炭副产品可以作为能源来源，有助于减少温室气体排放。
3. 3.The mining industry has been focusing on developing technologies to extract more valuable coal by-products from the seabed.
   矿业正在关注开发技术，从海底提取更有价值煤炭副产品。