STM Article Repository

This study aimed to separate potassium ion from calcium ion, which reduces the purity of the potassium, when they are extracted and recovered from incineration ash, and to reduce the environmental load of the final waste liquid. Potassium tartrate can be obtained by performing extraction using acetic acid, a weak acid, adding tartaric acid to the filtrate to separate calcium as calcium tartrate, and finally concentrating and evaporating the solution. All the experimental tests were performed in batch mode. An acetic acid solution of 0.5 mol/L was used for extraction, and the extraction extent was 95.4% when the solid–liquid ratio was 1:20. After the extract was filtered, 10 mL of 10% tartaric acid was added to 20 mL of the extract, resulting in solid precipitation. After the solids were separated, and when potassium was dissolved in the acid, the recovery was 72% of the extract. The optimal condition for the syngenite method is the addition of a magnesium dose of 5 mmol/L, and at pH 11 the Ca:K ratio is 1:2.1 with 42mol % K. This can be a suggestion as to which method is more effective and efficient in the recovery of K.