Slag Processing in Sandustry

Every Wet Sand batch that crosses your Shakers produces Gold (20–25% proc) and Slag. Beginners treat slag as waste; optimized factories treat it as delayed gold. The slag chain is: Slag → burn → Burnt Slag → Kinetic Slag Press → more Gold. Skipping burn or press steps leaves a large fraction of your income on the floor. This guide connects shaker output to Refining 2 and Tools research.

Where Slag comes from

Shakers separate gold from processed sand. Material that does not fall as gold exits as Slag — a distinct particle type with its own physics (Materials). If slag piles under shakers, grates clog and shaker gold rate drops. Always route slag sideways or onto a belt the moment shakers produce it.

Link your shaker bank design from How to Get Gold with a dedicated slag lane before scaling shaker count.

Slag press factory gameplay in Sandustry

Research gates

Tech	Unlocks	Role in slag chain
Refining 1	Shakers	Creates Slag
Refining 2	Kinetic Slag Press	Converts Burnt Slag to Gold
Tools	Flamethrower	Burns Slag without lava geography
Guns	(branch)	Alternative burn/combat tools depending on build

Refining 2 is non-optional for press gold. Flamethrower (Tools branch) matters when you lack convenient Lava. Priority relative to Logistics is debated; see Research Priority Tier List — most players finish a stable shaker line, buy Logistics, then pursue Refining 2 before deep side branches.

Step 1 — Collect Slag safely

Options by game stage:

• Manual bins — Fine for first two shakers.
• Conveyor belt — Logistics 1; slag rides to a central burn hall (Automation Basics).
• Launchers — Lift slag to an elevated burn track above lava pools.

Keep slag away from Wet Sand belts. Cross-contamination forces filter research early or jams shakers. Filters research helps but should not replace clean layout discipline.

Step 2 — Burn Slag to Burnt Slag

Burnt Slag is the press feedstock. Two burn sources appear in standard gameplay:

Flamethrower (Tools research)

Portable, reliable, player-controlled. Ideal for early burn lanes where you manually ignite slag streams or hold a flame on conveyor-fed piles. Pairs with Lights when burning deep underground (Dig Deeper).

Lava

Environmental heat source. Route slag conveyors over lava pools or drip slag into lava chambers for passive burn. Faster at scale but requires map placement and safety tiles so gold pickups and buildings do not melt.

Burn until particles convert to Burnt Slag — verify visually and on Materials if a batch looks mixed.

Step 3 — Kinetic Slag Press

Build the Kinetic Slag Press (Refining 2) with:

• Input lane for Burnt Slag only (filters help).
• Output collection for Gold and any byproducts your build displays.
• Power/throughput headroom — press starvation while shakers overproduce slag means backlog, not efficiency.

Press gold stacks with shaker gold for research purchases. Use Production Ratio Helper to match press count to slag volume from your shaker bank.

Layout patterns

Side-by-side refinery (compact)

Shaker diagonal row → slag belt parallel → burn trench (flamethrower or lava) → burnt slag belt → single press → gold merge pit.

Vertical burn stack (mid-game)

Launchers lift slag to an upper burn floor; burnt slag falls into press inputs below. Saves horizontal space when digging narrow shafts.

Buffered burn (high throughput)

Slag silo (large bin) feeds burn lane during peak shaker output. Smooths RNG spikes from gold procs without pausing mining.

Pick a pattern that matches your dig site — do not copy horizontal blueprints in a vertical cave without replanning water and power routes (Water Management).

Throughput tuning

Signs your slag line is mis-tuned:

• Slag piles reclaim shaker grates → gold per minute falls.
• Burnt slag backs up before press → add press capacity or slow shakers temporarily.
• Unburned slag hits press input → gold loss; fix burn lane length or flame coverage.
• You burn slag faster than shakers produce → redirect effort to sand mining (Dig Deeper).

Slag processing adds second-stream gold without extra Wet Sand cost — marginal return is high once built.

Interaction with other systems

• Vacuum (Tools) — Cleanup and recovery in tight burn rooms.
• Cryoblaster — Situational; know it exists for hazard control, not core slag math.
• Drones — Haulers move slag pre-logistics; Diggers feed sand upstream.
• Planter Boxes — Parallel economy; do not fund planters before press if gold-starved.

Early Access and demo notes

Core slag → burn → press logic matches the factory loop described for Early Access (2026-08-13, Steam/GOG/Microsoft Store/PC Game Pass). Demo availability may gate Refining 2 or Tools — confirm on Release Date and Platforms. Mechanics in this guide follow the published EA loop from Lantto Games / Hooded Horse.

Checklist before calling slag “done”

• Every shaker routes slag off the grate within seconds.
• Burn lane converts 100% of slag intended for press (no bypass piles).
• Press input sees mostly Burnt Slag.
• Gold from press merges with shaker gold for research.
• Buildings page matches your placed machine versions.

Slag processing separates adequate factories from optimized ones. Shakers fund research; the press funds luxury automation and deep digs.