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The Longquan pluton is a rare Caledonian granitic rock mass in southern Zhejiang. Studies on the Longquan pluton using petrology, geochemistry, and chronology were conducted in this paper, which reveal that it is composed of granite-monzogranite assemblage (granitoid) and tonalite-trondhjemite-granodiorite assemblage (TTG). The two types of rocks are generally enriched in large ion lithophile elements Rb, Ba, Th, U and K, and depleted in high field strength elements Nb, Ta, P and Ti, showing the characteristics of island arc magmatic rocks. The geochemical characteristics of the TTG rocks show that they belong to the typical high-pressure type TTG, and its magma originated from the remelting of the basic lower crust under the action of subducted slab fluid. While the granitoids were mainly derived from partial melting of ancient crustal sediments. Neither of them was significantly contaminated by mantle. The zircon SHRIMP U-Pb and LA-ICP-MS U-Pb dating results show that the Longquan pluton was formed between 443±3 Ma~410±3 Ma. Combined with its petrological and geochemical characteristics, it is indicated that the subduction of oceanic crust had still existed in the Longquan area until early Devonian.

The recovery of As from copper anode slime by chlorination leaching--NaH2PO2 selective reduction process was studied. The effects of liquid volume to solid mass ratio, initial acidity, leaching temperature, initial Cl- mass concentration and leaching time on the leaching rate of As. The effects of reduction temperature, molar ratio of NaH2PO2 to As and reduction time on the precipitation rate of As were investigated. The results show that the optimum chlorination leaching conditions are initial acidity of 220 g/L, liquid volume to solid mass ratio of 6/1, leaching temperature of 70 °C, initial Cl mass concentration of 150 g/L and leaching time of 2.5 h. The optimum reduction conditions are reduction temperature of 80 °C, molar ratio of NaH2PO2 to As of 2/1, reduction time of 2 h. Under the optimal conditions the average mass fraction of As is 90.44%, and the product quality can meet the refining requirements of elemental arsenic. [ABSTRACT FROM AUTHOR]