State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
J Environ Manage. 2023 Aug 1;339:117899. doi: 10.1016/j.jenvman.2023.117899. Epub 2023 Apr 11.
Foundry dust is the main refractory solid waste in the foundry industry, and its resource utilization is a top priority for realizing green and cleaner production. The massive amount of coal dust in foundry dust is a potential impediment to the recycling of foundry dust, and the efficient separation of coal dust is crucial to solving the above problems. In this paper, the flotation separation of coal dust from foundry dust enhanced by pre-soaking assisted mechanical stirring was reported. The influence of pre-soaking, stirring speed, and stirring time on the flotation results of foundry dust was systematically studied, and the enhancement mechanism was analyzed based on the microstructure and hydrophobicity of foundry dust. Flotation kinetics experiments with different stirring time were conducted to clarify the flotation process of foundry dust. The results indicate that the pre-soaking of foundry dust is beneficial for the water-absorbing swelling of clay minerals coated on the surface of coal dust, and the subsequent mechanical stirring pretreatment promotes the monomer dissociation of foundry dust, which increases the contact angle of foundry dust and considerably improves the flotation results. The optimal stirring speed and stirring time were 2400 rpm and 30 min, respectively. The classical first-order model presented the highest degree of fitting with the flotation data among the five flotation kinetics models. Therefore, the pre-soaking assisted mechanical stirring is a promising method for promoting flotation separation and the complete recycling of foundry dust.
铸造粉尘是铸造行业主要的耐火固体废弃物，其资源化利用是实现绿色清洁生产的首要任务。铸造粉尘中大量的煤粉是阻碍铸造粉尘回收利用的潜在因素，而煤粉的高效分离对于解决上述问题至关重要。本文报道了采用预湿辅助机械搅拌强化从铸造粉尘中浮选煤粉的方法。系统研究了预湿、搅拌速度和搅拌时间对铸造粉尘浮选效果的影响，并基于铸造粉尘的微观结构和疏水性分析了强化机理。进行了不同搅拌时间的浮选动力学实验，以阐明铸造粉尘的浮选过程。结果表明，铸造粉尘的预湿有利于包覆在煤粉表面的黏土矿物的吸水膨胀，随后的机械搅拌预处理促进了铸造粉尘的单体解离，增加了铸造粉尘的接触角，显著提高了浮选效果。最佳搅拌速度和搅拌时间分别为 2400rpm 和 30min。在五种浮选动力学模型中，经典的一级模型与浮选数据的拟合程度最高。因此，预湿辅助机械搅拌是促进浮选分离和实现铸造粉尘完全回收的一种很有前途的方法。
