Application of EDTA Coordination Titration Method in Field Detection of Zinc in Polymetallic Ores

The accuracy and speed of zinc detection in polymetallic ores directly affect the accuracy and efficiency of field zinc exploration. At present, the transportation of polymetallic ore samples to the laboratory for testing has problems such as long addition cycles, insufficient stability and accuracy in detecting high levels of zinc. The effects of different methods of removing organic matter and sulfur from polymetallic ore samples, different oxidants, whether the sample solution was centrifuged, and different ammonia removal methods on the detection speed, stability, and accuracy of zinc in polymetallic ore samples were compared. A EDTA coordination titration method that can quickly detect zinc in polymetallic ore samples in the field was developed. Using this method, six parallel analyses were conducted on four polymetallic national standard materials with low, medium, and high zinc content. The relative deviation and relative error of zinc content were 0.00% to 2.11% and 0.00% to 2.41%, respectively. The research results indicate that using high-temperature calcination to remove organic matter and sulfur from polymetallic ore samples, and centrifuging and filtering the polymetallic ore sample solution can greatly improve the sample pretreatment speed. The use of milder oxidants and dropwise addition of hydrochloric acid for ammonia removal can improve the stability and accuracy of the detection method.