Spent anodes (butts) are the remaining portion of prebaked anodes after consumption, which are reintroduced into the production of prebaked anodes after treatment. Among these residues, the main harmful element, sodium, tends to accumulate with the repeated recycling of the butts. This accumulation increases the air reactivity of prebaked anodes and consequently reduces their quality. In this study, aluminum sulfate hydrothermal acid leaching was used to remove sodium from the butts. The effects of leaching temperature, Al 3+ concentration, leaching time, and liquid-to-solid ratio on the removal of sodium from the butts were investigated. The sodium removal rate reached 99.42% at a leaching temperature of 90°C, an Al 3+ concentration of 1.5 mol/L, a leaching time of 2.5 h, and a liquid-to-solid ratio of 25 mL/g. This method significantly reduced the sodium content in the butts, offering a new approach for the high-quality recovery of the butts.
Owing to the selective oxidation and uneven combustion that occur on the surface of carbon anode, some carbon particles detach and form carbon residue, which is defined as spent anode slag (SAS). The highly graphitized and toxic impurities such as fluorite (CaF 2 ), corundum (α-Al 2 O 3 ), and cryolite (NaAl 11 O 17 ) are crucial components of SAS resource but are difficult to separate from graphite. This study developed a method of using water-soluble (emulsified) kerosene to separate the carbon particles from the toxic impurities in the SAS resource. The flotation purification approach of utilizing conventional kerosene was experimentally investigated and compared with that of using water-soluble kerosene. The results showed that with the use of emulsified kerosene, the maximum combustible matter recovery of the carbon particles was 89.86% while that of using traditional kerosene was 80.30%. The emulsified kerosene was comprehensively examined by various instruments to clarify its adsorption mechanism on the carbon particle surfaces. Because of the superior dispersibility of emulsified kerosene, it effectively envelops carbon particles with a smooth surface, oxygen-containing functional groups, and hydrophilic C–F bonds, thereby increasing the surface hydrophobicity and flotation responses of targeted carbon particles.
危险品化学品经营许可证（带存储）