兰炭（又称半焦 semi coke）结构为块状，粒度一般 分为 焦粉0-6mm, 小料 6-18 mm ,中料18-35 mm, 大料35-80 mm ，颜色呈浅黑色。兰炭由精煤块烧制而成的，是一种新型的炭素材料，其固定炭高、比电阻高、化学活性高、含灰份低、铝低、硫低、磷低的特性，以逐步取代冶金焦而广泛运用于电石、铁合金、硅铁、碳化硅等产品的生产，成为一种性价比更优的炭素材料。 兰炭可代替冶金焦而广泛用于化工、冶炼、造气等行业。
Half coke (also known as semi coke) structure is block-like, the particle size is generally divided into coke powder 0-6 mm, small material 6-18 mm, medium material 18-35 mm, large material 35-80 mm, light black color. Semi coke is made of refined coal blocks, is a new type of carbon material, its fixed carbon high, high specific resistance, high chemical activity, low ash content, low aluminum, low sulfur, low phosphorus, in order to gradually replace metallurgical coke and widely used in the production of calcium carbide, ferroalloy, ferrosilicon, silicon carbide and other products, become a more cost-effective carbon material. Semi coke can replace metallurgical coke and is widely used in chemical, smelting, gas and other industries.