火 on the left is the fire radical, a flame with three rising tongues. It tags 炼 as a heat-treatment word, grouping it with 烧 (burn), 烤 (roast), and 煮 (boil) - smelting and refining are all things done with sustained flame.
东 on the right is a simplified replacement for the older phonetic 柬 found in the traditional 煉. It now serves as a graphic stand-in rather than a true sound match, the kind of trade-off the 1956 simplification often made for stroke economy.
