{'fraction_non_alphanumeric': 0.028645833333333332, 'fraction_numerical': 0.021484375, 'mean_word_length': 5.404166666666667, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Recovery of soluble chlorides from municipal solid waste incineration fly ash using evaporative crystallisation and flotation methods

ABSTRACT Fly ash contains large amounts of soluble chlorides, including KCl, NaCl, and CaCl2. Currently, KCl and NaCl from the wastewater obtained after washing are separated mainly via evaporative crystallization, whereas CaCl2 is preferentially precipitated using Na2CO3. These methods present poor separation performance of KCl and NaCl. In this study, evaporative crystallization was used to simultaneously separate KCl and NaCl mixture from CaCl2. The solubility test results and theoretical recoveries of KCl and NaCl were used as a basis for the experiments. The recoveries of NaCl and KCl were 92.73% and 92.70%, respectively. Contact angle tests were performed to evaluate hydrophobicity of KCl and NaCl surfaces. The contact angle of a KCl–NaCl saturated solution containing flotation reagents on NaCl and KCl was 0° and 28.2°, respectively, indicating the complete hydrophilicity of NaCl and hydrophobicity of KCl. Separation of KCl and NaCl via flotation was analyzed and the effects of collectors, collector concentration, depressants, and pH on flotation efficiency were determined. Under optimal conditions, the grade and total recovery of KCl were 98.31% and 91.43%, respectively, whereas those of NaCl were 96.62% and 90.00%, respectively. Therefore, the combination of evaporative crystallization and flotation can be a promising method for separating soluble chlorides from fly ash.