May 15 (Reuters) - Belgium's Umicore named Bart Sap as its chief executive officer, replacing Mathias Miedreich who has decided to step down, the materials technology and recycling group said on Wednesday.

Sap joined Umicore in 2004 and has been the executive vice president of its Catalysis arm since March 2021. His appointment as CEO is effective May 16, the company said.

Umicore, which makes catalytic converters and battery materials for carmakers, forecast 2024 core profit below expectations in February as costs from its production ramp-up and capacity expansion weighed on earnings at the company's battery materials business.

The battery materials unit, which the company is banking on to offset the phasing out of internal combustion engines, will still be burdened with start-up costs this year, but the burden should be gone by 2025, Miedreich told Reuters in February. (Reporting by Shreya Biswas in Bengaluru; Editing by Shounak Dasgupta and Mohammed Safi Shamsi)