## Materials and Methods
### Design of Recipes  
The optimal design of recipe for biocarbon briquettes depending on binder type, binder ratio, and compaction pressure was derived from 27 tests. Reference recipe (R0) was produced from coke breeze and cement as binder, while recipes R1-R6, as given in Table 2, were produced from 45-50% of coke breeze, 25% of charcoal 1 and 10% of cement while different binders (molasses, wood tar, bitumen and lignin) were tested. The compaction pressure was fixed for all at 160 MPa. Table 3 shows the composition of recipes R7-R15 that were designed for briquetting of Charcoal 2, which has lower carbon and higher ash content compared to Charcoal 1. The recipes were designed with/without coke breeze and different types of binders. Higher content (50-80%) of Charcoal 2 is applied in recipes R7-R9 compared to R0 (0% charcoal) or R4 (25% Charcoal 1). Recipes R10 and R11, with composition simulating R4, were used to produce briquettes under compaction pressure of 80 and 160 MPa, respectively, to investigate the effect of the compaction pressure and charcoal type on the briquettes' strength. The binding efficiency of Keracool binder [13] was examined in recipes R11-R13. Recipe R14 was designed to simulate R4 (Charcoal 1), while R15 (10% cement) was designed to simulate R8 (without cement). Recipes R16-R27 were designed with higher content of Charcoal 1, aiming at increasing the contribution of biocarbon in briquettes and optimizing the mechanical strength and reactivity by using different types of binders and other additives, as given in Table 4. R16-R21 were designed to investigate the effect of molasses content with/without cement and at different mixing ratios of hydrated lime. R16 and R17 were developed with same composition but different types of cement; Portland cement and calcium aluminate (CA) cement, respectively. The effect of silica suspension on charcoal reactivity was assessed in R22-R24. Recipes R25-R27 were designed to evaluate the effect of compaction pressure on briquette quality and the results were compared to R18, which was produced at 160 MPa. After designing the recipes, the materials were thoroughly mixed to produce homogeneous mixtures and ensure that the binders are well-distributed in the mixtures. A laboratory hydraulic press with compaction pressures up to \(\sim\)160 MPa and a stainless-steel mould (\(\mathcal{O}\) = 40 mm) were used for briquetting. Further recipes were designed for upscaling of the briquettes using a bigger-sized mould (\(\mathcal{O}\) = 70 mm) and compaction pressure up to \(\sim\)160 MPa, as given in Table 5. Several briquettes were produced for each recipe under the same compaction condition. Reproducibility of the results was checked for all measurements. The moisture contents of the mixtures and briquettes were measured using moisture analyzer HB43-S Halogen by Mettler Toledo. The large-scale samples were tested in high-temperature experiments. Recipe M1 containing coke breeze and cement was used as reference for comparison. In recipes M2-M5, two types of hydrated \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Materials** & **Moisture,** **\%** & **Ash, \%** & **VM, \%** & **C-Fix,** **\%** & **C-Total,** **\%** & **H, \%** & **N, \%** & **O, \%** & **S, \%** & **HHV,** \\  & **\%** & **(db)** & **(db)** & **\% (db)** & **(db)** & **(db)** & **(db)** & **(db)** & **(db)** & **MJ/kg** \\ \hline Charcoal 1 & 3.5 & 0.7 & 18.6 & 80.7 & 87.0 & 3.4 & 0.2 & 8.3 & 0.0 & 31.1 \\ Charcoal 2 & 2.4 & 39.2 & 11.6 & 49.2 & 54.2 & 1.6 & 0.1 & 4.8 & 0.0 & 18.4 \\ Coke breeze & 8.6 & 11.4 & 0.6 & 87.8 & 86.8 & 0.2 & 1.3 & 0.2 & 0.5 & 30.9 \\ Molasses & 19.0 & 5.6 & 88.4 & 6.1 & 42.7 & 3.8 & 0.9 & 52.6 & 0.78 & 15.0 \\ Wood tar & 12.6 & 4.1 & 67.9 & 28.0 & 40.0 & 6.3 & 0.1 & 53.7 & 0.0 & 21.6 \\ Bitumen & 0 & 1.7 & 22.0 & 70.0 & 85.7 & 5.3 & 1.9 & 3.6 & 1.8 & 41.4 \\ Lignin & 11.0 & 0.8 & 59.6 & 39.6 & 59.3 & 5.9 & 0.1 & 26.7 & 1.2 & 26.9 \\ Nanocellulose & 10.9 & 0.7 & 88.3 & 10.9 & 43.3 & 6.5 & 0.2 & 49.3 & 0.0 & 17.2 \\ \hline \hline \end{tabular}
\end{table}