Table 1. Physical and chemical properties of biochars.
Properties of maple and spruce sawdust biochar made in an 80 L batch pyrolyzer with highest treatment temperature between 350–450 °C (from Sackett et al. (2015)), and maple/birch sawdust biochar produced in a flow-through screw fed pyrolyzer with highest treatment temperature of 500–600 °C. Three replicates were used for each characterization.
| Attribute | Maple flow through BC | Maple batch BC | Spruce batch BC |
|---|---|---|---|
| Moisture (%) | 2.7 (0.0) | 2.43 (0.15) | 2.4 (0.100) |
| Ash (%) | 2.74 (0.06) | 1.67 (0.06) | 0.65 (0.06) |
| Volatile matter (%) | 29.87 (3.07) | 29.64 (2.64) | 21.38 (0.32) |
| Fixed carbon (%) | 64.68 (3.07) | 66.25 (2.64) | 75.57 (0.32) |
| pH | 7.39 (0.23) | 7.7 (0.50) | 6.5 (0.0) |
| EC (μS/cm) | 105 (4) | 75 (10) | 72 (14) |
| Elemental composition | |||
| C (%) | 85.01 (2.3) | 77.3 (3) | 77.9 |
| N (%) | 0.71 | 0.10 (0.01) | 0.01 |
| S (%) | n/a | 0.02 (0.0) | 0.01 |
| Phosphorous (mg/kg) | n/a | 197 (16) | 75 |
| Ca (mg/kg) | n/a | 6,015 (944) | 2,419 |
| K (mg/kg) | n/a | 3,443 (105) | 1,243 |
| Mg (mg/kg) | n/a | 619 (6) | 285 |
| Particle size distribution | |||
| > 4,000 μm (%) | 0.76 (0.95) | 0.40 (0.11) | 3.09 (1.91) |
| 2,000–4,000 μm (%) | 15.37 (1.52) | 5.61 (0.91) | 17.39 (0.98) |
| 500–2,000 μm (%) | 57.25 (2.63) | 31.53 (2.54) | 59.14 (0.89) |
| 250–500 μm (%) | 13.49 (0.84) | 27.74 (2.43) | 11.44 (0.227) |
| 125–250 μm (%) | 9.18 (2.42) | 25.32 (0.74) | 7.05 (0.59) |
| 125–63 μm (%) | 3.63 (1.48) | 9.02 (0.36) | 1.85 (0.31) |
| < 63 μm (%) | 0.30 (0.15) | 0.39 (0.16) | 0.01 (0.02) |
Note:
Values not determined are abbreviated as n/a, not applicable.