Abstract: With waste strontium slag in the production of strontium carbonate by carbon reduction of lapis lazuli as raw mate- rial，using hydrochloric acid as the leaching agent，the influences of strontium slag particle size，leaching temperature，leach- ing time，and solution acidity etc.on the leaching rate of strontium were investigated.On the basis of that the leaching process was optimized by orthogonal experiments.The optimum acid leaching process conditions were obtained：strontium slag particle size of 0.062 mm，the reaction time of 2 h，the reaction temperature of 30 ℃，and leaching liquid pH=0.1.This study can pro- vide reference for raising the utilization coefficient of strontium resources.

Key words: waste strontium slag, hydrochloric acid leaching, strontium leaching rate, key parameters