Question: who invented the process to remove impurities by blasts of cold air blown through heated iron
[{'answer': 'Song Dynasty', 'provenance': [{'wikipedia_id': '40180', 'title': 'Bessemer process', 'start_paragraph_id': 7, 'start_character': 153, 'end_paragraph_id': 7, 'end_character': 165, 'bleu_score': 1.0, 'section': 'Section::::History.:Early history.\n'}]}, {'provenance': [{'wikipedia_id': '40180', 'title': 'Bessemer process', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 731, 'bleu_score': 0.9526401996952971, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 590212314090091472}, 'section': 'Section::::History.:Early history.\n'}]}]