Combining Multiple Methods for Recycling of Kish Graphite from Steelmaking Slags and Oil Sorption Performance of Kish-Based Expanded Graphite

Popcorn-Inspired Expanded Graphite Microspheres with Controlled Morphology and Considerable Conductivity

The structured processing of graphite is complex and challenging, in which expanded graphite plays a crucial role. Given its superior physical and chemical properties, expanded graphite finds extensive application in diverse domains such as electrochemistry and thermal management. However, the traditional preparation process is inconvenient in effectively meeting the design requirements on the macro and micro scales, which presents a challenge for the structured processing of expanded graphite materials. Here, an innovative method is first proposed for the controllable preparation of expanded graphite microspheres. Inspired by the explosion process of popcorn, the controlled gas release inside the natural flake graphite during chemical expansion is regulated by fuming sulfuric acid, realizing the controllable preparation of expanded graphite microspheres. Subsequently, sulfur trioxide can also intensify the degree of oxidation on the surface of the microspheres. The controllable microsphere morphology endows the composite with good isotropic network bonding, with considerable thermal conductivity of 1.703 W m-1 K-1 at low loading of 10 wt.% and reliable cyclic stability. This work opens up a new way for the morphology control of expanded graphite and provides a novel design thought for the physical and chemical structure control of carbon materials in the future.

Amino-Modified Graphene Oxide from Kish Graphite for Enhancing Corrosion Resistance of Waterborne Epoxy Coatings

Waterborne epoxy (WEP) coatings with enhanced corrosion resistance were prepared using graphene oxide (GO) that was obtained from kish graphite, and amino-functionalized graphene oxide (AGO) was modified by 2-aminomalonamide. The structural characteristics of the GO and AGO were analyzed using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). And the anti-corrosive performance of waterborne epoxy-cased composite coatings with different addition amounts of AGO was investigated using electrochemical measurements, pull-off adhesion tests, and salt spray tests. The results indicate that AGO15/WEP with 0.15 wt.% of AGO has the best anti-corrosive performance, and the lowest frequency impedance modulus increased from 1.03 × 108 to 1.63 × 1010 ohm·cm-2 compared to that of WEP. Furthermore, AGO15/WEP also demonstrates the minimal corrosion products or bubbles in the salt spray test for 200 h, affirming its exceptional long-term corrosion protection capability.

Investigation of the enrichment-purification process and electrochemical performance of kish graphite in dust from blast furnace tapping yard

Kish graphite is a typical byproduct of steel production, and its enrichment and purification are essential prerequisites for its high value and comprehensive utilization. To solve the problem of recovery and application of difficult-to-treat kish graphite with a small particle size obtained from metallurgical dust, kish graphite in blast furnace tapping yard dust was effectively enriched and purified by a comprehensive flotation-acid leaching treatment process in this study. The influence of the flotation agents on the flotation process was explored. The results showed that the optimized flotation agent dosage was 500.0 g·t-1 (collector) and 120.0 g·t-1 (frother), respectively. Based on the optimized flotation scheme, a graphite concentrate (FG) with 79.12 % carbon content and 93.5 % carbon recovery was obtained. After the leaching treatment with a HCl-HF mixed acid solution, the carbon content of the graphite concentrate increased to 95.55 %. The ID/IG value of the graphite concentrate was 0.145, and the average lattice spacing was approximately 0.3354 nm. The SEM results showed that the leaching-treated graphite concentrate (AFG) had a loose, fragment-like structure. When used as an anode material for lithium-ion batteries, The AFG still provided a high reversible capacity of ∼370 mAh·g-1 and excellent coulombic efficiency of 99.6 % after 350 cycles. In addition, an industrial-grade recycling and utilization path for kish graphite based on a circular supply chain strategy was proposed. The results of this study may serve as a conceptual basis for the recovery and application of kish graphite from metallurgical dust.