CaCO3 + Au → Ca + AuCO3

This is an oxidation-reduction (redox) reaction:

CIV + e- → CIII (reduction)

Au0 - 3 e- → AuIII (oxidation)

CaII + 2 e- → Ca0 (reduction)

CaCO3 is an oxidizing agent, Au is a reducing agent, CaCO3 is an oxidizing agent.

Reactants:

  • CaCO3 – Calcium carbonate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Other names: Calcite; aragonite; chalk; Lime (material); Limestone; marble; oyster; pearl; source: wikipedia, accessed: 2019-09-27, Calcium salt of carbonic acid source: wikidata, accessed: 2019-09-02, Children's Mylanta Upset Stomach Relief source: wikidata, accessed: 2019-09-02
    • Appearance: Fine white powder; chalky taste source: wikipedia, accessed: 2019-09-27; White powder or pellets source: ICSC, accessed: 2019-09-04
  • Au
    • Names: Gold source: wikidata, accessed: 2019-09-07, Au source: wikidata, accessed: 2019-09-07, Element 79 source: wikidata, accessed: 2019-09-07, Aurum source: wikidata, accessed: 2019-09-07

Products:

  • Ca
    • Names: Calcium source: wikidata, accessed: 2019-09-07, Calcium (powder) source: ICSC, accessed: 2019-09-04, Ca source: wikidata, accessed: 2019-09-07
    • Appearance: Silvery-white-to-grey powder source: ICSC, accessed: 2019-09-04
  • AuCO3