3 sentences

1. 废铁被投入炼钢炉中熔化。

   fèi​tiě bèi tóu​rù liàn​gāng lú zhōng róng​huà.

   Scrap iron was put into the steel furnace to melt.

   Source: Dong Chinese Dictionary

2. 传说太上老君的炉里炼出了一颗神丹。

   chuán​shuō Tài​shàng Lǎo​jūn de lú lǐ liàn​chū le yī kē shén​dān.

   Legend has it that a divine elixir was refined in Taishang Laojun's furnace.

   Source: Dong Chinese Dictionary

3. 妈妈正在炉子上煮汤。

   mā​ma zhèng​zài lú zi shàng zhǔ tāng.

   Mom is cooking soup on the stove.

   Source: Dong Chinese Dictionary