Urine stone

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Urine stone is a yellowish-brown crystalline deposit that forms in solid or pasty form when the urine precipitates in toilets and urinals . Urine stone is caused by a chemical reaction of hard water (usually the rinse water) with the urine . Lime dissolved in water and other dissolved substances combine with the urine and uric acid as a catalyst to form an insoluble lime-magnesia compound. This compound is a mixture of calcium or magnesium carbonate , oxalate , phosphate and sulfate . The resulting solids consist of the minerals struvite , hydroxyapatite and calcite . The mixture solidifies due to a high pH value , which is created by the bacteria involved in the breakdown of urea . Fresh urine initially has a low pH. Since rainwater does not contain lime, there is no urine scale when rainwater is used to flush toilets and urinals. Apart from the amount of urine and lime content of the water, the length of time the urine remains in the siphon and other collection points primarily determines the amount of urine stone that occurs. In contrast, the volume of the rinsing water used has little influence. Even with urinals, the clogging of the siphon is not only caused by the contents of the urine. Often it is organic substances such as dust, grease, skin particles, hair as well as cigarette butts and handkerchiefs thrown into the urinal that ultimately cause constipation. If the blockage is to be removed without mechanical measures, the organic components should first be removed with an alkaline pipe cleaner . Most drain cleaner granules contain sodium hydroxide to dissolve organic matter. After thorough rinsing, the urine stone can then be decomposed with acid . Acid and alkaline agents must never be used together as this can lead to violent reactions.

The use of hydrochloric acid with a concentration of 25% to 30% allows the removal of thick limescale deposits that have formed over years with a sufficiently long exposure time. Work should be done with protective equipment and with good ventilation. Ceramics are not attacked by hydrochloric acid, but hydrochloric acid can damage fittings or pipes made of metal. If the urine stone deposits are not very strong, weaker acids such as acetic acid or citric acid can be used if they can act for a sufficiently long time.

  • Toilet with urine scale deposits

  • Lumps of urine

See also

Individual evidence

  1. ↑ Household cleaners - experiments for everyday chemistry lessons. (PDF) p. 5 , archived from the original on November 19, 2014 ; Retrieved November 19, 2014 .
  2. ↑ a b K.M. Udert, R. Högger, TA Larsen, W.Gujer: Urine precipitation in urinals and NoMix toilets. (PDF) Federal Institute for Water Supply, Wastewater Treatment and Water Protection (EAWAG), Dübendorf, p. 8 , archived from the original on November 19, 2014 ; Retrieved November 19, 2014 .
  3. ↑ SOS. How do you do that? What you really have to be able to do! P. 102 [1]
  4. ↑ Hotel & Technology. (PDF) January 2012, p. 56 , archived from the original on November 19, 2014 ; Retrieved November 19, 2014 .