Series: Mining & Materials • Part 12 of 14
Circular Industry: Waste = Input
We designed the campus like a living organism: heat is food, water is blood, and “waste” is a roommate with a job. In this part we wire the loops — metal, heat, water, gases, minerals — so neighbors feed neighbors and nothing wanders off.
Today’s mission
Map every byproduct to a buyer next door.
Publish pre‑calculated loop sizes.
Prove a campus can be quiet, clean, and net‑useful to its town.
Why circular (physics first, romance second)
We don’t “offset” — we interlock. The same electrons (Part 3) that melt metals (Parts 4–6) also run pumps, kilns (Part 9), and data halls (Part 11). That lets us route heat, water, and byproducts on purpose: every outflow is a menu, and the whole campus is hungry.
- Short loops win: moving heat 80 m is cheaper than piping fuel 800 km.
- Standard ports: MEC‑48/96 keep swaps quick (Part 10).
- Ship shapes, not waste: tailings/bricks/blocks stay local (Parts 1, 8, 9).
Materials loops (scrap, cullet, and friends)
Metals
- Steel: EAF melts scrap from our own mills & customers. Typical closed‑loop scrap rate: 20–35% of output.
- Aluminum: remelt returns <10% of virgin energy; keep a clean scrap stream per alloy (Part 6).
- Copper: chop & refine shop rejects → ER → 99.99% cathode; dross heads back to anodes.
Glass & silicon
- Cullet: 20–35% batch by mass; cuts energy and melter wear (Part 9).
- PV offcuts: return to glass batch or aluminum rails; cells go to specialized recyclers; we design for disassembly (Part 3).
Packaging & pallets
Reusable steel/aluminum pallets with bolt‑on corners. They come home on backhauls, get scanned, and go again. Cardboard gets one job: protect optics, then into the paper loop.
Heat loops (no plume, just neighbors)
Sources (typical campus)
| Unit | Grade | Recoverable | Notes |
|---|---|---|---|
| EAF off‑gas & canopy | Med/High | ~8–15 MWth | To steam, dryers |
| Glass anneal/temper | Low/Med | ~6–12 MWth | To dryers, buildings |
| Electro‑refining hall | Low | ~1–3 MWth | Air→water coils |
| Compute racks (Part 11) | Low | ~18–20 MWth | Liquid loop 45–60 °C |
Sinks (where heat earns a living)
- Product dryers (ore, bricks, coatings)
- Domestic hot water & building HVAC
- Low‑temp process steps (pickling, wash)
- District loop to town pool, greenhouses, laundries
Rule of thumb: catch everything above 30 °C. If a stream isn’t useful today, store it or move it 80 m to someone who smiles.
Water loops (closed by default)
Network anatomy
- Raw → process → polish → recycle; blowdown to blocks/binders.
- Rain from PV meadows feeds make‑up; lake buffers seasons (Part 1).
- Separate clean/dirty loops so clean stays clean.
Planning numbers
| Line | Recycle rate | Make‑up | Notes |
|---|---|---|---|
| Metals cooling | ~90–98% | ~2–10% | Closed towers/HEX |
| Glass & coaters | ~85–95% | ~5–15% | Filters + RO |
| Battery metals | ~80–95% | ~5–20% | Depends on leach route |
Blowdown mineralizes blocks (Part 9) instead of meeting a river.
Gases & reagents (make chemistry behave)
Byproduct → Product
| From | Becomes | Used by |
|---|---|---|
| Smelter SO₂ (Cu sulfides) | H₂SO₄ (sulfuric acid) | Leach shops (battery metals) |
| LC³ e‑calciner CO₂ | CO₂ stream | Carbonation cure for blocks |
| Compute pumps & drives | Low‑grade heat | Dryers • HVAC • Greenhouses |
| Glass baghouse fines | Fine silica | Binder blends • blocks |
Reagent sanity
- Prefer sulfate, ammonia, and carbonate systems with known closures.
- Enclose vapor paths; scrub to product (acid/base) rather than vent.
- Design neutralization to yield saleable solids, not mystery mud.
Where does CO₂ for curing come from, exactly?
From the electric calciner (Part 9): limestone in LC³ releases CO₂ at controlled temps. Because the kiln is sealed and electric, we capture and compress that stream for curing blocks and panels. Short loop, no smokestack.
Mineral byproducts → products (nothing wanders off)
EAF & smelter slags
- Screen and magnet: coarse → road base, fines → binder blend (with LC³).
- Age/steam treat to lock free lime; certify like any material.
Concentrator & tailings
- Sand‑rich tails to pressed blocks (Part 9) cured with CO₂.
- Clay‑rich fines to calcined clay for LC³ (Part 9).
But is it safe?
We only upcycle inert, tested streams with continuous QA. Anything that won’t behave becomes a stabilized, lined monolith — and we keep shrinking that category.
Campus loop ledger (pre‑calculated)
“One‑Gigaton Campus” — example ties (steady‑state)
Roughly: steel 1 Mt/yr • glass 1 Mt/yr • battery chemicals 0.1–0.3 Mt/yr • compute 20 MW.
| Loop | Flow | From | To | Note |
|---|---|---|---|---|
| Scrap steel | ~0.25 Mt/yr | Mills/customers | EAF | 25% closed‑loop return |
| Al scrap | ~0.12 Mt/yr | Extrusions | Remelt | Low energy remelt |
| Cullet | ~0.25–0.35 Mt/yr | Glass lines | Melter batch | 20–35% of batch |
| H₂SO₄ | ~0.2–0.5 Mt/yr | Cu smelter | Leach shops | SX/EW & polish |
| CO₂ | ~0.05–0.12 Mt/yr | LC³ calciner | Block cure | Short‑loop cure gas |
| Low‑grade heat | ~30–40 MWth | Compute & lines | Dryers/HVAC | 45–60 °C loop |
| Process water | ~85–95% recycle | All lines | Water net | Make‑up via rain & lake |
| Slag/sand to blocks | ~0.2–0.6 Mt/yr | Mills/tails | Block plant | CO₂‑cured |
Values are planning points to keep designs concrete; actuals dial in by site recipe.
Scoreboard (targets)
- Materials circularity: ≥ 90% internal by mass (ex‑product)
- Water recycle: ≥ 90% average across loops
- Heat capture: ≥ 70% of recoverable low/med grade
- Waste to landfill: ≤ 1–3% of total mass flow, stabilized
Neighbor benefits
- District hot water at cost (schools, pools, clinics)
- Blocks & panels priced for local builds
- Jobs tied to maintenance and QA — the quiet kind
Pre‑calculated scenarios
Scenario A — Steel + Glass duet
Steel 1 Mt/yr + Solar glass 1 Mt/yr.
| Loop | Value | Note |
|---|---|---|
| Heat reuse | ~20–30 MWth | EAF & anneal → dryers/HVAC |
| Cullet fraction | ~25–35% | Cuts melter kWh/t |
| Scrap return | ~25–30% | Internal & customer scrap |
| Water recycle | ~90–95% | Two‑loop design |
Scenario B — Copper + Battery metals
Copper cathode 1 Mt/yr + Ni/Co sulfates 100 kt/yr.
| Loop | Value | Note |
|---|---|---|
| SO₂ → H₂SO₄ | ~0.2–0.5 Mt/yr | Feeds leach • no flares |
| ER heat | ~2–4 MWth | Air→water coils to dryers |
| Water recycle | ~85–95% | Polishing + RO |
Scenario C — Compute‑anchored town
Compute 20 MW + bricks/blocks 0.5 Mt/yr + community loads.
| Loop | Value | Note |
|---|---|---|
| Waste heat to district | ~18–20 MWth | 45–60 °C supply |
| CO₂ cure gas | ~0.05–0.12 Mt/yr | From LC³ calciner |
| Water recycle | >90% | Heat‑pump dryers |
The data hall becomes a civic utility: quiet heat in winter, quiet cooling in summer.
Q&A
“Is zero‑waste realistic?”
Zero‑landfill is realistic; zero‑mass isn’t. We design so >90% of mass stays in loops, 7–9% becomes products for others, and the small, misbehaving remainder is stabilized and stored properly — while we keep shrinking it.
“What happens if a loop is down?”
We keep buffers: thermal tanks, reagent tanks, and laydown for blocks. MEC ports (Part 10) let us reroute quickly. If a neighbor naps, storage bridges the hour/day until it wakes.
“How do you prove it to neighbors?”
Continuous monitors on air, water, and noise with public dashboards. If a line hiccups, alarms go to both us and the town. Trust is a design parameter, not a press release.
Up next — Communities Around Lakes (Part 13 of 14). We’ll plan towns that grow around the future lakes from Part 1 — schools, markets, and homes that sip energy and love the view.