Enhancing flotation of smithsonite by using 1,3,5-Triazinane-2,4,6-trithione as sulfidation

1,3,5-Triazinane-2,4,6-trithione (TMT) was used for the first time as a sulfidation agent in the flotation of smithsonite. Results showed that 80.5% recovery rate could be obtained in the presence of TMT $(5 × 10^{-5} mol$ / $L)$ and butyl xanthate $(5 × 10^{-4} mol$ / $L)$. However, the recovery rate was only 59.4% when sodium sulfide $(5 × 10^{-5} mol$ / $L)$ was used. Micro-flotation test and contact angle measurement showed that TMT activation was better than sodium sulfide activation. Besides, the contact angle increased from 32.44° (untreated) to 89.58° (treated with TMT), which was significantly higher than 50.2° (treated with sodium sulfide). Fourier Transform Infrared spectroscopy(FT-IR) and Zeta potential test showed the chemisorption of TMT on the smithsonite surface. The results of ICP spectral detection and solution chemistry calculation revealed that $Zn_3TMT$ complex precipitates in the smithsonite pulp were formed on the mineral surface at pH 6.5. A hydrophobic film was also formed on the mineral surface after TMT treatment, and more adsorption sites were provided for butyl xanthate. Thus, the adsorption of collector was significantly enhanced

Selective Recovery of Copper from Acid Leaching Solution through Slow Release Sulfide Precipitant

A new kind of sulfide precipitant, namely, slow release sulfide precipitant (SRSP), was developed and prepared first to realize the selective recovery of copper from an acid leaching solution. The experimental results indicated that SRSP as a precipitant could selectively and efficiently recover copper and the high purity of copper sulfide slag with a Cu grade of 48.16%, and a Cu recovery rate of 97.84% could be obtained. Moreover, copper in leaching solution could be recovered more efficiently and selectively by SRSP compared with Na2S. The results of H2S gas release, chemical reaction energy calculation, and SEM image analyses illustrated that realizing the selective recovery of copper mainly depended on the ions of S2− and HS− produced by the dissolution of SRSP. Moreover, the concentrations of S2− and HS− should always be kept at a low level in the process of selective recovery of copper; this is the biggest difference from the traditional precipitant and the key to preventing the escape of H2S gas in the copper recovery process. More pivotally, SRSP provides an alternative sulfide precipitant for the selective recovery of copper from the acid leaching solution of copper smelting dust

Selective Recovery of Copper from Acid Leaching Solution through Slow Release Sulfide Precipitant

A new kind of sulfide precipitant, namely, slow release sulfide precipitant (SRSP), was developed and prepared first to realize the selective recovery of copper from an acid leaching solution. The experimental results indicated that SRSP as a precipitant could selectively and efficiently recover copper and the high purity of copper sulfide slag with a Cu grade of 48.16%, and a Cu recovery rate of 97.84% could be obtained. Moreover, copper in leaching solution could be recovered more efficiently and selectively by SRSP compared with Na2S. The results of H2S gas release, chemical reaction energy calculation, and SEM image analyses illustrated that realizing the selective recovery of copper mainly depended on the ions of S2− and HS− produced by the dissolution of SRSP. Moreover, the concentrations of S2− and HS− should always be kept at a low level in the process of selective recovery of copper; this is the biggest difference from the traditional precipitant and the key to preventing the escape of H2S gas in the copper recovery process. More pivotally, SRSP provides an alternative sulfide precipitant for the selective recovery of copper from the acid leaching solution of copper smelting dust

Geographical distribution of drinking-water with high iodine level and association between high iodine level in drinking-water and goitre: a Chinese national investigation. Br J Nutr (epublication ahead of print version 15

Abstract Excessive iodine intake can cause thyroid function disorders as can be caused by iodine deficiency. There are many people residing in areas with high iodine levels in drinking-water in China. The main aim of the present study was to map the geographical distribution of drinking-water with high iodine level in China and to determine the relationship between high iodine level in drinking-water and goitre prevalence. Iodine in drinking-water was measured in 1978 towns of eleven provinces in China, with a total of 28 857 water samples. We randomly selected children of 8 -10 years old, examined the presence of goitre and measured their urinary iodine in 299 towns of nine provinces. Of the 1978 towns studied, 488 had iodine levels between 150 and 300 mg/l in drinking-water, and in 246 towns, the iodine level was .300 mg/l. These towns are mainly distributed along the original Yellow River flood areas, the second largest river in China. Of the 56 751 children examined, goitre prevalence was 6·3 % in the areas with drinking-water iodine levels of 150-300 mg/l and 11·0 % in the areas with drinking-water iodine .300 mg/l. Goitre prevalence increased with water and urinary iodine levels. For children with urinary iodine . 1500 mg/l, goitre prevalence was 3·69 times higher than that for those with urinary iodine levels of 100-199 mg/l. The present study suggests that drinking-water with high iodine levels is distributed in eleven provinces of China. Goitre becomes more prevalent with the increase in iodine level in drinking-water. Therefore, it becomes important to prevent goitre through stopping the provision of iodised salt and providing normal drinking-water iodine through pipelines in these areas in China