Enhanced Rock Weathering Lab

Model agricultural enhanced rock weathering (ERW), silicate dissolution kinetics, soil porewater bicarbonate leaching, permanent ocean carbon storage, avoided limestone emissions, and 10-year project finance.

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Deployment Presets:
Net LCOR
$0.0
per net t CO2 removed
Net CDR Delivered
0k t
10-yr verified removals
Carbon Efficiency
0.0%
after supply chain loss
10-Yr Project NPV
$0.0M
@ 8.0% discount rate
Unlevered IRR
0.0%
project equity return
Simple Payback
0.0 Yrs
working capital payback
Agronomic & Geological Controls
1. Farmland Scale & Mineralogy
20,000 ha
20 t/ha
µm
2. Soil Chemistry & Climate Kinetics
3. Supply Chain Logistics & Milling
4. Carbon Pricing & MRV Verification
Levelized Cost of Carbon Removal (LCOR) Stack
Soil-to-Ocean Biogeochemical Weathering Cycle
10-Year Silicate Dissolution & CO2 Trapping Curve
10-Year Project Cash Flow & Breakeven Payback
Technical & Financial Pro-Forma Summary
Geochemical & Carbon Accounting
Total Rock Spread: 400,000 tons
Weathering Rate (SCM): 15.2% (Yr 1) / 78.4% (10-Yr)
Gross Silicate Carbon Removal: 94,080 t CO2
Supply Chain Logistics Emissions: 15,680 t CO2
Avoided Limestone Aglime Emissions: 48,294 t CO2
Net Permanent Carbon Removal: 126,694 t CO2 net
Deployment Economics & Project Returns
Total Upfront Working Capital: $10,480,000
Total Delivered Cost per Ton Rock: $30.00 / ton rock
Gross Carbon Removal Revenue: $22,804,920
10-Year Cumulative Net Profit: $10,804,592
Net Carbon Developer Margin: +$85.3 / net ton CO2
5x5 Sensitivity Matrix: Truck Haul Distance vs. Carbon Removal Credit Price

Evaluates the dual sensitivity of Net LCOR ($/t CO2) and 10-Year Project Net Present Value ($M) across truck freight haul radius and certified voluntary carbon credit pricing.

Truck Haul \ Carbon Price $140 / t CO2 $170 / t CO2 $200 / t CO2 $230 / t CO2 $260 / t CO2
Engineering Guide: Enhanced Rock Weathering & Soil Biogeochemistry
1. The Geochemical Carbon Sink Mechanism

Over geological epochs, natural silicate rock weathering regulates Earth's climate by consuming atmospheric carbon dioxide. Rainfall absorbs ambient $\text{CO}_2$, forming dilute carbonic acid ($\text{H}_2\text{CO}_3$). In soils, root and microbial respiration supercharges carbonic acid concentrations up to 100 times atmospheric levels.

When finely ground silicate minerals (such as forsterite $\text{Mg}_2\text{SiO}_4$ or calcium-rich basalt) contact acidic soil porewater, mineral dissolution releases divalent cations ($\text{Mg}^{2+}, \text{Ca}^{2+}$) and converts aqueous $\text{CO}_2$ into stable bicarbonate ions ($\text{HCO}_3^-$):

Mg₂SiO₄ + 4CO₂ + 4H₂O → 2Mg²⁺ + 4HCO₃⁻ + H₄SiO₄

Dissolved bicarbonate ions leach into deep aquifers, flow into rivers, and accumulate in the global ocean, where the average residence time exceeds $100,000\text{ years}$—making ERW a truly permanent carbon removal pathway with zero physical leakage risk.

2. Avoided Agricultural Lime & Soil Agronomic Co-Benefits

Millions of tons of agricultural limestone ($\text{CaCO}_3$) are applied globally every year to neutralize soil acidity. Paradoxically, when limestone dissolves in acidic soils, it releases gaseous $\text{CO}_2$ ($\sim 0.44\text{ t CO}_2/\text{t limestone}$).

Because crushed silicate rocks neutralize hydrogen ions without containing carbonate, ERW completely displaces agricultural lime—eliminating upstream calcination and field emissions. Furthermore, silicate rock releases crucial plant nutrients:

  • Bioavailable Silicon (H4SiO4): Strengthens plant cell walls, improving resistance to drought, fungal disease, and pest pressure.
  • Magnesium & Calcium: Vital macro-nutrients for chlorophyll synthesis and soil cation exchange capacity (CEC).
  • Documented Yield Increases: Multi-year agricultural field trials demonstrate $5\%\text{ to }15\%$ yield increases in crops including corn, soybeans, sugarcane, and wheat.
Formative Assessment: Enhanced Rock Weathering Mastery
1. How does spreading crushed silicate rock on agricultural soil chemically trap atmospheric carbon dioxide?
2. Where is the captured carbon ultimately stored, and what is its expected permanence?
3. Why does replacing traditional agricultural limestone (CaCO3) with crushed silicate rock provide an immediate carbon bonus?
4. What are the two largest parasitic carbon emissions penalties in the ERW life cycle that must be deducted to calculate net CDR?
Frequently Asked Questions

Enhanced rock weathering accelerates the Earth's natural chemical weathering cycle by grinding silicate rocks (such as volcanic basalt or olivine) into fine powder and spreading them across agricultural soils. Rainfall and plant roots generate carbonic acid in soil porewater, which dissolves the rock minerals into divalent cations (Mg2+, Ca2+) and dissolved bicarbonate (HCO3-). These bicarbonate ions leach through groundwater and rivers into the ocean, permanently locking carbon for over 100,000 years.

The most widely deployed rock is volcanic basalt because it is globally abundant, non-toxic, contains low heavy metal concentrations, and provides rich micronutrients (calcium, magnesium, iron, phosphorus, and silicon). Ultramafic rocks like olivine or dunite have higher theoretical carbon capture capacity (up to 0.85 t CO2/t rock) but require careful monitoring of trace nickel and chromium. Industrial silicate byproducts like steel slag and wollastonite are also evaluated.

Silicate minerals consume hydrogen ions during dissolution, de-acidifying acidic soils and raising soil pH just like agricultural limestone (CaCO3). However, traditional limestone releases carbon dioxide gas when dissolving in acidic soils (~0.44 t CO2 per ton of limestone). Silicate rocks neutralize acidity without releasing CO2, displacing agricultural lime while supplying bioavailable silicon and micronutrients that enhance crop yields by 5% to 15%.

Measurement, Reporting, and Verification (MRV) combines solid-phase soil core analysis, immobile element tracer ratios (such as titanium, zirconium, or strontium isotopes), soil porewater lysimeter sampling, river catchment monitoring, and calibrated geochemical kinetic models (such as the Shrinking Core Model) verified by independent carbon registries like Puro.earth or Isometric.

The levelized cost of carbon removal (LCOR) ranges from $80 to $160 per net ton of CO2 removed. The primary cost components are quarry rock procurement ($10–$25/ton), mechanical milling to 50–100 microns ($15–$35/ton), truck freight logistics ($0.12–$0.18/ton-km), agricultural spreader contracting ($15–$25/ha), and scientific MRV verification ($10–$18/t CO2).
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