V3 · Sonnet

One drop of brine

A dish, a drop and a ledger of what has left it. The water goes, the salt does not: evaporate and watch where the salt stays. This is a simplified model, not a measurement of brine from Ciechocinek.

A dish with a drop of brine, seen from above The author's own diagram. In the middle of the dish lies a drop in which 48 black dots of salt float. Above the dish a row of 24 markers records how much water has evaporated: a grey dot is a 1/24 part of the initial water that has not yet evaporated, a blue stroke is a part that has. In the initial state there are only grey dots. As the drop shrinks, the salt does not disappear: once the saturation limit is passed, the dots turn into black squares of deposit. The exact figures are given in the ledger alongside.
The author's own diagram, not a photograph or a measurement. View from above: the markers above the dish show the water that has evaporated (one stroke = 1/24 of the initial water; a grey dot is a part that has not yet evaporated, and in the initial state there are only dots), the dashed circle is the outline of the initial drop, and the bar on the left is the whole sample from top to bottom. One salt mark = 0.083 g (48 marks make up all the salt). The area of the drop is proportional to the mass of the liquid at constant depth; a full dish = 500 g.
  • vapour (outside the vessel)
  • water in the liquid
  • dissolved salt (dot)
  • deposit (square)

In the vessel (liquid + deposit) of 100.00 g at the start

100.00 g
Initial sample
  • Vapour, outside the vessel 0.00 g 0.00 % of the initial water
  • Liquid in the vessel 100.00 g water 96.00 g · dissolved salt 4.00 g · concentration 4.00 %
  • Deposit (crystal) 0.00 g 0.00 % of all the salt
  • Total, balance closed 100.00 g of 100.00 g
range 0 to 96.00 g

Horizontal axis: evaporated water, from 0 g to 96.00 g.

Vertical axis: concentration of the liquid, scale 0–30 %.

The dashed marker on the slider and the vertical line on the chart show the saturation limit.

Three scenes, three jumps to the same sample:

All 4.00 g of the salt is dissolved in 96.00 g of water; the concentration is 4.00 %.

Change the sample and the solubility limit

50–500 g, step 10 g

share of salt in the mass of the sample, 2–8 %

set in the model, 20–40 g of salt per 100 g of water

Changing the parameters keeps the amount of evaporated water already set, as long as it fits within the new range.

Without JavaScript the controls are hidden, and the drawing and the ledger show the initial state (48 salt marks, 24 grey dots on the axis). Four points of the default sample are calculated in the table below.

The limit: where concentration stops telling the story

Up to the limit, everything is simple. Vapour takes away only water, so the same salt sits in less and less liquid and the concentration rises.

concentration = dissolved salt ÷ (water + dissolved salt)

The limit is set in the model: the largest amount of salt that 100 g of water holds in solution. Once the liquid reaches it, the concentration stops at a wall. Evaporation goes on, but the figure for “concentration” no longer says anything about how much water has gone. The state of the sample is then described by the mass of the deposit.

past the limit: dissolved salt = water in the liquid × limit ÷ 100, deposit = total salt − dissolved salt

On the chart by the slider, the solid line is the concentration before the limit and the dashed line is its plateau after the limit. The dot shows the current point; in the dry state there is no dot, because there is no liquid and the concentration cannot be calculated.

Saturation concentration in the model
26.42 %
Limit reached at evaporation of
84.86 g
… that is, of the initial water
88.39 %
Past the limit: deposit per 1 g of vapour
0.359 g
Default sample: 100 g, 4 % salt, limit 35.9 g / 100 g of water. The values were calculated by the author of the page using the formulas alongside and rounded to 0.01 g; they are not a measurement.
PointVapourLiquidDepositConcentration of the liquid
Start0.00 g100.00 g0.00 g4.00 %
Limit84.86 g15.14 g0.00 g26.42 %
Past the limit90.00 g8.15 g1.85 g26.42 %
Dry salt96.00 g0.00 g4.00 gno liquid

What the model does not know

  • The system. The model assumes a solution of a single salt in water. The material from which this page was made does not give the composition of the brine from Ciechocinek, so no claim is made here about how it behaves.
  • The solubility limit. The default 35.9 g per 100 g of water comes from an earlier version of the page; the source of this figure is not in the material and needs to be identified. The 20–40 g range is an illustrative choice.
  • No temperature and no time. The horizontal axis is the amount of evaporated water, not hours or days. The limit is constant, with no supersaturation, and the deposit does not retain water or liquid.
  • No other losses. Mass is lost solely as water vapour.
  • The drawing is a schematic. The scale of the drop assumes a constant depth, and the positions of the salt marks are conventional.

The page is not a process manual or an assessment of salt yield.

What changed relative to V2

  • Three phase columns were replaced by a single dish and three rows of the ledger. The same numbers, fewer competing objects.
  • Five presets were cut down to three scenes. The presets “graduation towers 75 % of water” and “salt-boiling house 90 % of water” were removed: those percentages were not process data.
  • The four buttons for the stages at Ciechocinek were turned into a plain list below. The geography is a pointer, not a second experiment.
  • The photograph of the graduation towers that was embedded from outside has been replaced by a link in the sources; the page works offline.
  • Kept: the sample mass, the salinity, the conventional limit, the 0.01 g step, a balance accurate to the gram and protection against division by zero.

The route of the brine in Ciechocinek

A pointer to the place the question comes from. The model assigns no numbers to any of the stages. The descriptions come from the sources listed below; V3 did not check their content again.

  1. Grzybek

    The fountain encloses brine source no. 11. According to Uzdrowisko Ciechocinek, the intake is 415 m deep and supplies brine to the graduation towers and, beyond them, to the salt-boiling house. [2]

  2. Graduation towers

    A link in salt production, used for evaporating brine. [2]

  3. Salt-boiling house

    The concentrated brine goes into flat, open vessels called pans; the museum describes how salt crystals form. The Polish Geological Institute lists Ciechocinek among the places using the traditional pan method. [3] [1]

  4. Crystal

    The salt boilers take the salt out onto a wooden drying rack. [3]

Sources

  1. PIG–PIB: Warzelnictwo i wytwarzanie produktów zdrojowych [Salt boiling and the production of spa products] — the pan method and the tradition of crystallisation in Polish spa towns.
  2. Uzdrowisko Ciechocinek: Szlak Solankowy [The Brine Trail] — intake no. 11 (the Grzybek fountain, depth 415 m) and its pipeline connection to the graduation towers.
  3. Muzeum Warzelni Soli [Salt-Boiling House Museum] — pans, the process of crystallising the liquid and the work of the salt boilers taking salt out onto a wooden drying rack.
  4. Photograph of the graduation towers, not embedded on the page: Wikimedia Commons, author Przemek P, licence given with the file: CC BY-SA 3.0. Link carried over from V2.
  5. Source of the value for the solubility of salt in water (default 35.9 g / 100 g of water): not supplied in the material; needs to be identified and checked.

Links 1–4 were carried over from the previous version. V3 neither opened nor verified them, and their state after deployment is checked by the integrator.