Opti̇mi̇zati̇on of the producti̇on of zi̇nc ni̇trate from smi̇thsoni̇te(znco3)

In this study, the optimization of dissolution conditions of zinc in the smithsonite ore (ZnCO3) which was supplied from a region of Hakkari, in nitric acid solution was determined by using Taguchi method. In order to gain a different perspective of production, on the basis of the amount of zinc dissolved under optimum conditions, the production of zinc nitrate which uses in many industries as textile, pharmaceutical, chemistry is intended. The orthogonal array experimental design plan L25 (55) with five parameters and five levels, Taguchi's developed from the standard test plans, was chosen to determine the optimum conditions. The parameters relating to the dissolution process were determined as reaction temperature, solid-to-liquid ratio, acid concentration, reaction time and stirring speed. The particle size of the ore used was chosen in the range of –200 +160 μm. As a result of the experiments, the zinc concentration was analyzed for using Atomic Absorption Spectrometer (AAS) and voltammetric devices. The results obtained by AAS and voltammetry devices were compared and were found to be compatible with each other. For the Taguchi method, statistical calculations were performed using Minitab-16 software package. The optimum conditions based on the results of AAS and voltammetric analysis were found as reaction temperature 50oC, solid-to-liquid ratio 1/100 (g/ml), acid concentration 15%, reaction time 60 min and stirring speed 1000 min-1 (rpm). The most significantly effective parameter in the process of dissolution is temperature and then the influence of the other parameters are determined as stirring speed, acid concentration, reaction time and solid to liquid ratio, respectively. Under the optimum dissolution conditions, verification experiments showed dissolution amount of zinc as 99.98% for AAS and 99.66% for voltammetric. Predicted dissolved quantity according to Taguchi method was found to be 99.24% for voltammetric while it was 99.80% for AAS. According these results, the prediction values were seen as consistent with the results of AAS and voltammetric. Under optimum conditions zinc nitrate compound was produced from smithsonite ore and the compound's structure was confirmed by XRF and XRD analysis.