抄録
We made a study regarding four different decomposing methods in order to produce potassium carbonate or sulfate.
1. When Engel's salt is agitated in hot water, it is decomposed into basic magnesium and carbonate solution as indicated in the following formula:
4 (KHCO3·MgCO3·4H2O)→2K2CO3+3MgCO3·Mg(OH)2·3H2O+CO2+14H2O
By concentrating this solution, crystalized potassium carbonate can be obtained. In this case, the yield of potassium amounts to approximately 95%.
2. When Engel's salt is agitated withMagnesium hydroxide in cold water, it is decomposed into magnesium carbonate and potassium carbonate solution.
2(KHCO3·MgCO3·4H2O)+Mg(OH)2→K2CO3+MgCO3·3H2O+H2O
By this method, it requires much time to complete reaction, and in order to increase the purity of crystalized potassium carbonate, the quantity of magnesium hydroxide to be added must be equivalent to that of Engel's salt. In this case, the yield of potassium is 75%.
3. When Engel's salt is calcined, it is decomposed into magnesia and potassium carbonate.
2 (KHCO3·MgCO3·4H2O)→2MgO+K2CO3+3CO2+9H2O
The solubility of this potassium carbonate against coldwater is so high that when the calcination is extracted by cold water, potassium carbonate can easilybe separated from magnesia. In this case, the yield of potassium amounts to 92%.
4. When the mixture of Engel's salt and magnesium sulfate is agitated in hot water, potassium sulfate solution and basic magnesium carbonatecan be obtained asindicated in the following formula:
8(KHCO3·MgCO3·4H2O)+4MgSO4→3 (3MgCO3·Mg(OH)2·3H2O)+4K2SO4+4CO2
When this solution is concentrated, crystalized potassium sulfate can be obtained. The yield of potassium in this case amounts to 92%-94%, and magnesium sulfate to be added to Engel's salt must be equivalent Engel's salt in quantity.
