SGL Carbon (Germany)

In the ICARUS project, European partners collaborate to develop and scale innovative technologies for recovering and refining secondary raw materials from silicon photovoltaic (PV) manufacturing. The production of photovoltaic modules generates significant quantities of waste, particularly silicon kerf, graphite, and silica residues from ingot and wafer manufacturing. ICARUS aims to transform these waste streams into high‐value secondary materials suitable for reintegration into the PV value chain and other industrial applications. Four industrial pilot‐scale processes are developed, targeting the purification and reuse of these materials. Results from the pilots demonstrate both the technical feasibility and economic potential of substituting these recovered materials for virgin and critical raw materials. This work provides a viable pathway toward a more resource‐efficient and circular PV manufacturing industry.

Highly <111>-oriented 3C-SiC coatings with distinct surface morphology consisting of hexagonally shaped pyramidal crystals were prepared by chemical vapor deposition (CVD) using silicon tetrachloride (SiCl4) and toluene (C7H8) at T ≤ 1250 ℃ and p = 10 kPa. In contrast, similar deposition conditions, using methane (CH4) as carbon precursor, resulted in randomly oriented 3C-SiC coatings with a cauliflower-like surface of SiC crystallites. No excess carbon was detected in the highly <111>-oriented 3C-SiC samples despite the use of aromatic hydrocarbons. The difference in the preferred growth orientation of the 3C-SiC coatings deposited using C7H8 and CH4 as carbon precursors is explained via quantum chemical calculations of binding energies on various crystal planes. The adsorption energy of C6H6 on the SiC (111) plane was 6 times higher than that on the (110) surface. On the other hand, the CH3 exhibited equally strong adsorption on both planes. This suggests that the highly <111>-oriented 3C-SiC growth in the C7H8 process, where both C6H6 and CH3 are considered the main active carbon-containing film forming species, is due to the highly preferred adsorption on (111) planes, while the lower surface energy of the (110) plane controls the growth orientation in the CH4 process, in which only CH3 contributes to the film deposition.

Abstract This chapter presents the most relevant advances achieved during the MIDES project in relation to material development of key elements for microbial desalination cells. The first section is devoted to electrodes. Providing a general overview of the requirements of carbon-based materials to serve either as anodes or cathodes for microbial desalination cells. Advances achieved during MIDES in the development of materials for anode and cathode application are listed. The second section is focussed on ion-exchange membranes for microbial desalination cells. General considerations for the use of these membranes are reported as well as key parameters. Finally, advances in ion-exchange membrane development, in terms of antifouling and their performance in desalination trials, achieved during the MIDES project, are reported.

Polygranular carbon and graphite bodies are composite materials consisting of filler grains embedded in a binder matrix. Such materials show remarkable properties, e.g. increasing strength with increasing temperature, excellent electrical and thermal conductivity for graphite materials, and almost electrical and thermal insolating behavior of carbon material. A rough overview of oxidation behavior in common industrial atmospheres is provided, too.

Production and processing of bulk products, e.g. phosphoric acid, hydrochloric acid, hydrofluoric acid, titanium white, sulfuric acid, trichlorosilane and others, require large-scale process equipment. Since these chemical media are extremely hazardous, the thermal process equipment, e.g. heat exchangers and columns as well as pumps and reactors, must fulfill highest demands on mechanical robustness and on heat transfer properties and have to provide excellent corrosion resistance. In this chapter a survey is given of said equipment and systems that are widely used in industry.

Synthetic graphite became a key material for the use in nuclear power plants. This comprises the use for construction purpose as well as moderator material to maintain the nuclear chain reaction by slowing down fast neutrons. Graphite material resists not only high temperatures but also the lattice damage caused by the neutron bombardment. Although the changes in the physical properties of graphite are dramatic, it maintains its integrity. Despite decades of research not all of these radiation-induced alterations have been completely understood.

The best way to reduce the brittleness of SiC ceramics is the reinforcement of SiC with carbon fibres. In this chapter an overview about carbon fibre reinforced SiC is given. It will inform about the different production ways by chemical vapour infiltration (CVI), impregnation of inorganic polymers (PIP) and reactive melt impregnation (MPI) with liquid silicon. The resulting material behaviour of the different material types is discussed and an overview about current applications is given.

The sp2-hybridization of the carbon atoms is the cause for the formation of flat hexagonal layers. The regular parallel stacking of these carbon layers cause the unique electrical and mechanical properties of the perfect graphite crystal. More than this, these properties are of extreme anisotropy. As an example, the coefficient of thermal expansion is negative in the layer plane (−1,5 10–6 K−1) and rather highly positive perpendicular to the stacked layers (18,5 10-6K-1). However, neither natural graphite nor synthetic graphite posses the ideal form of the graphite lattice. Consequences are deviations in their properties, depending on the severity of structural defects. If the severity of lattice defects does not allow a regular parallel stacking sequence of the graphitic layers, the substance is a so called non-graphitic carbon. In some cases, these defects can be repaired by a thermal treatment above 2500 K. In other cases, the carbon material remains non-graphitic, even after such an extreme heat treatment. Responsible is the transition phase through which the carbonaceous precursor passed through during the early carbonization treatment. Graphitic and non-graphitic forms of carbon materials can be distinguished by X-ray diffraction investigations. Logically consistent of this is the broad diversity in crystallinity and morphology, i.e. the wide spectrum of properties and thus applicability of carbon and graphite materials.

Carbon electrodes are, in contrast to Söderberg electrodes, prebaked by the manufacturer. The granular components consist of synthetic graphite and calcined anthracite. Carbon electrodes are used in submerged arc furnaces to produce silicon, phosphorous, non-ferrous metals and ferroalloys. The electrode dimensions can be up to 1400 mm in diameter and 3500 mm in length. The electrode weight can be up to 7 t per piece. The annual consumption is more than 200 00 t worldwide

The combination of two active materials into one positive electrode of a lithium‐ion battery is an uncomplicated and cost‐effective way to combine the advantages of different active materials while reducing the disadvantages of each material. In this work, the concept of binary blends is extended to ternary compositions. The combination of three different active materials provides high versatility in designing the properties of an electrode. Therefore, the unique properties of a layered oxide, phospho‐olivine, and spinel type material are mixed to design a high‐energy cathode with improved environmental friendliness. Four different compositions of blend electrodes are investigated, each with individual benefits. Synergistic effects improved the rate capability, power density, thermal and chemical stability simultaneously. The blend electrode consisting of 75 % NMC, 12.5 % LMFP and LMO provides similar energy and power density as a pure NMC electrode while economizing 25 % cobalt and nickel.