Preparation of Kish graphite-based graphene nanoplatelets by GIC (graphite intercalation compound) via process

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.

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

The utilization of industrial waste as renewable resources is an essential issue of sustainable development. Kish graphite is a precipitate of excess carbon generated during the cooling of molten iron and one of the byproducts associated with steel slags. The scale-up recycling of kish graphite from steelmaking slags is a promising way to develop natural graphite alternatives. However, only one means cannot work efficiently because of the unusual occurrence of associated impurities; combining multiple separation methods is the solution. In this paper, we proposed an integrated beneficiation process, pneumatic separation-flotation-sonication-magnetic separation, to recycle kish graphite flakes with a high graphitization degree and investigated the sorption performance of various oils on kish-based expanded graphite. The new process avoided shortages such as the sediments of iron particles in the flotation cell and the loss of clean graphite in the magnetic separation. Consequently, the carbon content of kish graphite reached ∼95% after separation and >99% after acid leaching. The macroscopic structural defects of kish particles created more active sites, made the intercalation of KG-GICs faster, and yielded better-staged compounds. The kish graphite-based expanded graphite presented an octopus-like shape and exhibited an expansion volume of ∼150 mL/g. Furthermore, the developed macropore structure of the obtained kish graphite-based expanded graphite led to a superior sorption performance for oils. This work supplies one feasible and promising way to recycle kish graphite from steelmaking slags and use it.

Millstone Exfoliation: a True Shear Exfoliation for Large-Size Few-Layer Graphene Oxide

A millstone (MS) was introduced in the production of large-size few-layer-graphene oxide (FLGO) via true shear exfoliation in order to minimize fragmentation. The MS was constructed with two glass plates, where the top plate was designed to rotate against the stationary bottom plate, thereby generating true shear force. Mildly oxidized graphite (MOG) was used for MS exfoliation in order to obtain both good property and high yield. The rpm of rotation (10, 20, 30, 40, and 50), solution concentration (0.5, 1, and 2 mg/ml), and number of exfoliation (1, 2, and 3) were optimized by measuring the UV-vis absorption, and the effect of oxidation time (30, 60, and 90 min) was studied under the given optimum conditions. Next, the FLGO was isolated by centrifugation and characterized by TEM and AFM. The FLGO obtained was as large as ~ 10 μm in size, which was slightly smaller than the pristine graphite, suggesting a possibility of slight fragmentation. But it was still much larger than the FLGO obtained via sonication (< 1 μm), demonstrating successful MS exfoliation.