Lime kilns of the Polish Jura · Rudniki near RędzinThe stone comes out lighter
From 100 kg of pure CaCO3, about 56 kg of quicklime (CaO) remains in the kiln. The other c. 44 kg leaves as gas. Mass is not lost; it only changes place: move the slider and see where each part of it is.
After full firing: from 100.0 kg of CaCO₃, 56.0 kg of CaO remains; 44.0 kg has left as CO₂.
A model diagram, not a measurement: a 100 kg batch of pure CaCO₃, molar masses 100.087 / 56.077 / 44.010 g/mol. Common height scale (dashed outline = 100 kg). Total: 100.0 kg. Values rounded to 0.1 kg.2 · Where the mass disappears in the kiln
The shaft kiln: stone down, gas up
The kiln works continuously. The stone sinks while hot gases and air rise from below. Choose a height in the shaft and see how much of the 100 kg of pure CaCO3 is still solid mass there.
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1 · Charging
Stone enters the shaft from the top in lumps. The batch still has its full mass and nothing has left it.
Solid mass of the batch: 100.0 kg of 100 kg
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2 · Drying and heating
Hot gases from below heat the sinking stone. Moisture in its pores evaporates and rises. The pure formula contains no moisture, so the mass does not change here yet. Moisture appears only in section 3.
Solid mass of the batch: 100.0 kg of 100 kg (pure CaCO₃)
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3 · Firing (the hottest zone)
Here the carbonate decomposes: CaCO₃ → CaO + CO₂. The gas rises through the charge while the solid lumps sink. Following Royal Society of Chemistry material, V2 gave a threshold of about 850–900°C. We have no measurements from the kilns in Rudniki, so the page does not draw a temperature profile. The centre of large lumps may not have time to react: this is underburning.
Where the heat comes from (fuel charged together with the stone, or a side fire-box) depends on the construction, and the material has no such information for Rudniki. The fuel combustion gases are not part of this balance.
Solid mass of the batch in this zone: from 100.0 to 56.0 kg of 100 kg
Dark: solid mass after firing. Hatched: mass that leaves here as gas. The exact split depends on the height within the zone.
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4 · Cooling and discharge
Cold air drawn in from below cools the sinking lime and is itself warmed. The quicklime is drawn off at the bottom. Its reaction with water (slaking) is a separate stage, outside this balance.
Solid mass of the batch: 56.0 kg of 100 kg; 44.0 kg left earlier as gas
3 · One batch, successive assumptions
The real charge is not pure CaCO3
Take out a batch of stone and add assumptions one at a time. The dashed line in the drawing is the textbook result. Watch the CaO bar fall below it. The compositions are model examples, not an analysis of stone from Rudniki.
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Dashed line: the CaO that pure CaCO₃ would give at full firing (56.0% of the charge mass). The drawing is in % of charge mass, on a common scale; a model, not a measurement.
Gas from the stone
- CO₂ from carbonate decomposition
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- H₂O vapour from the stone's moisture
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- Total gas from the stone
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Solid mass (at the bottom)
- Quicklime CaO
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- Underburnt stone (CaCO₃)
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- Mineral impurities
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- Total solid mass
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- CaO in the solid mass
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Outside the model
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4 · Limits of the model, place, sources
What leaves the kiln, and what this model does not calculate
CO₂ from carbonate decomposition is not the kiln's whole emission. The volatile phase in the model is only what comes from the stone itself. Fuel, moisture and incomplete firing have to be separated.
CO₂ from the carbonate
It follows from the mass of CaCO₃ and the degree of firing. At full firing it is about 44% of the mass of pure carbonate.
Water vapour from the stone
It follows from the assumed moisture content (0–15% is an assumption, not a measurement). This is mass that was never carbonate.
Underburnt stone and impurities
They are not an emission. They lower the share of CaO in the solid mass. The model treats impurities as inert and ignores sintering and side reactions.
Fuel combustion gases
Fuel produces its own CO₂ and water vapour. The type and amount of fuel in Rudniki are not in the material, so we insert neither a number nor zero here.
What is known about Rudniki
Information carried over from V2 on the basis of the sources cited there. It was not re-checked in this version.
- Place
- Rudniki near Rędzin, on the grounds of the “Rudniki” chemical works, ul. Fabryczna (according to a regional description).
- Structures
- Two brick shaft kilns with a circular plan and cylindrical chimneys.
- 1858
- Władysław Kanigowski builds lime kilns and starts production.
- 1923
- Smaller lime kilns merge into the “Wapnorud” lime works.
- Condition of the kilns
- Not in the material: we do not describe differences between the two kilns.
- Fuel, stone, temperatures
- No data for these structures.
- Access
- The grounds of an industrial plant. This page is neither permission to enter nor operating instructions.
Sources
- Śląskie Travel — Piece wapienne w Rudnikach koło Rędzin [Lime kilns in Rudniki near Rędzin]: location, two shaft kilns, the dates 1858 and 1923. Link carried over from V2, not opened when V3 was built, to be checked.
- Royal Society of Chemistry — Thermal decomposition of calcium carbonate: the decomposition equation, molar masses, the reaction with water. Link carried over from V2, to be checked.
- Michał Bulsa — Rudniki, wapienniki 02 [Rudniki, lime kilns 02]: photograph of 29 March 2022, CC BY-SA 4.0. It is not embedded because the page is meant to work offline; the photo opens at the source. Licence recorded as in V2, to be checked.
What changed relative to V2
- The charge-mass slider was replaced with a number field: mass scales only the kilograms, not the shares.
- Instead of a CaCO₃ content slider there is an impurities slider, and CaCO₃ is the remainder after moisture and impurities. Fewer conflicting controls.
- Three ready-made compositions were replaced with revealing assumptions one at a time, plus two examples, A and B.
- Removed the temperature ranges of the zones (no measurements) and the repeated result panels.