Development of Ammoniacal Leaching Processes; A Review

Abstract

Selective leaching processes for copper, gold, nickel, and cobalt have been investigated because there is an advantage of ammoniacal hydrometallurgy that metal such as copper could be selectively extracted restricting the dissolution of iron or calcium. In the present article, the studies for selective ammoniacal leaching of copper from motor scraps and waste printed circuit boards (PCBs), for ammoniacal leaching of gold to decrease the amount of cyanide used or to substitute cyanide by thiosulfate, and for ammoniacal leaching to recover nickel and cobalt from nickel oxide ore and intermidiate obtained from manganese nodule treatment process were summarized and further studies were proposed for domestic technology development for ammoniacal hydrometallurgy processes.

Synthesis of Cu and CuO nanoparticles from e-waste and evaluation of their antibacterial and photocatalytic properties

“…As a result, by leaching with ammoniacal ammonium chloride leachant, it can be retrieved from other metals in WPCBs. During the process, ammonium chloride provides anions to the copper ammine complex [Cu (NH 3 ) n 2+ ] as well as H + to react with OH − anion freed during the reaction as follows (Yoo and Kim, 2012 ):…”

Current Status of Gold Leaching Technologies from Low Grade Ores or Tailings

“…. 특히 Thiosulfate를 다른 보조제(주로 co-ligand 3,10,13) . 암모니아 존재하에서, 금이 Thiosulfate 와 결합되는 반응은 아래 식 (2)와 같이 표현된다 15) .…”

The ammonia leaching of alloy produced from waste printed circuit boards smelting process

“…Table 1 shows the weight and value distribution of metals in several kinds of PCBs (Hageluken, 2006;Le, Yoo, Jeong, & Lee, 2008). A larger amount of precious metals such as Ag, Au, and Pd was contained in the mobile phone PCBs than in the other PCBs (Hageluken, 2006;Le et al, 2008;Yoo & Kim, 2012).…”

“…In the ammonia leaching for copper, cupric (Cu 2þ ) amine could be used as oxidant, and the complex ions are able to be reused by electrical oxidation Koyama, Tanaka, Miyasaka, & Lee, 2006;Oishi, Koyama, Konishi, Tanaka, & Lee, 2007;Oishi, Yaguchi, Koyama, Tanaka, & Lee, 2008a, 2008b. Ammonia leaching processes have been developed and investigated to recover valuable metals such as copper, gold, silver, cobalt, and nickel (Yoo & Kim, 2012). However, there have been a few studies on the ammonia leaching of alloy obtained from smelting process of PCB scraps.…”

“…Ammonia leaching method is a representative leaching process under the basic condition, and this process has some advantages, compared with strong acid leaching processes, such as low toxicity, low cost by regenerating the solvent through evaporating, and insolubility of iron and calcium (Meng & Han, 1996;Yoo & Kim, 2012). In the ammonia leaching for copper, cupric (Cu 2þ ) amine could be used as oxidant, and the complex ions are able to be reused by electrical oxidation Koyama, Tanaka, Miyasaka, & Lee, 2006;Oishi, Koyama, Konishi, Tanaka, & Lee, 2007;Oishi, Yaguchi, Koyama, Tanaka, & Lee, 2008a, 2008b.…”