Determination of lead in phosphate ore by flame atomic absorption spectrometry with microwave digestion

The phosphate ore samples were pretreated by microwave digestion technique.The key factors such as acid medium,dosage,and the pressure and time of microwave digestion were investigated.Consequently,a determination method of lead in phosphate ore by flame atomic absorption spectrometry was established.The results indicated that in four acid mediums(hydrochloric acid,nitric acid,sulfuric acid and aqua regia),the sample dissolving effect in aqua regia was the best. Its proper dosage is 5 mL per grammes.The three-step microwave digestion procedure were adopted with digestion pressure and time: 0.3 Mpa/60 s,0.5 Mpa/360 s,1.0 Mpa/180 s. Compared with traditional acid solution method,the dissolving time of microwave digestion was short,and the sample dissolution was complete. The detection limit of method was 0.036 μg/mL.The proposed method was applied to the determination of phosphate ore samples.The relative standard deviation(RSD) was 4.1 %-6.6 %,and the recovery of standard addition was 94 %-108 %.