Hydrometallurgical Treatment for Mixed Waste Battery Material

Abstract

Abstract.Hydrometallurgical experiments are generally required to assess the appropriate treatment process before the establishment of the industrial recovery process for waste battery materials. The effects of acid systems and oxidants in metal leaching were studied. The comprehensive leaching effects of the citric acid were superior to the sulfuric acid. The potassium permanganate inhibits the dissolution of metals. Thermodynamic calculations showed that metals precipitate more easily in sulfuric acid system than in citric acid system. The Fe precipitation efficiency in sulfuric acid system was 90% at pH 3.5, but with considerable losses of Co (30%) and Ni (40%). The proper pH and organic/aqueous (O/A) ratio for Fe and Zn removal with Di-(2-ethylhexyl) phosphoric acid extraction were 2 and 0.5, respectively; while for the removal of Cu and Mn, the best pH and O/A ratio were 3 and 0.75, respectively. Crude manganese carbonate and a cobalt-nickel enriched liquid were obtained by selective precipitation in raffinate using an ammonium bicarbonate solution. In citric acid systems, the precipitation efficiency of Co, Ni, Mn, Fe, Cu and Zn were less than 20% at pH 7. The proper pH and O/A ratio for the separation of the metals in two groups (Ni/Co/Cu and Mn/Fe/Zn) were 1.5 and 2. The cobalt-nickel-copper enriched liquid was finally obtained. IntroductionRecovery of metals such as cobalt, nickel and manganese from secondary resources has been an important area of "urban minerals" exploitation. Cobalt and nickel secondary resources usually include spent lithium-ion batteries, nickel-metal hydride battery waste, metal scraps, complex mineral wastes and smelting slags [1]. Hydrometallurgical experiments for waste materials are often required to roughly acquire the treatment process before the establishment of any industrial recovery process. The recovery process often contains these steps: acidic leaching, metal separation and product synthesis. Due to the complex and diverse composition of secondary resources, the leaching methods are different. Sulfuric acid is commonly used in the leaching of spent batteries, and the extraction ratio of Co can achieve at least 70% [2]. In addition, some organic acids such as citric acid (C 6 H 8 O 7 ), malic acid (C 4 H 5 O 6 ), glycine, EDTA and DTPA, also were used to leach or extract metals of spent batteries or waste catalysts [3,4]. The leaching efficiency of major metals for these organic acids can also reach more than 70%. Apart from leaching agent, the oxidant is a key factor in promoting the dissolution of valuable metals during leach process. The use of hydrogen peroxide as an oxidizing agent can promote leaching of nickel, cobalt and rare earth from waste capacitors and batteries [5]. The use of potassium permanganate or hydrogen peroxide oxidation during acid leaching of indium sulfide minerals can significantly reduce the apparent activation energy and reaction order, increasing the reaction rate [6]. Potassium permanganate can also play the role of Mn remover [7]. Differ...

Leaching of Nickel and Cobalt from a Mixed Nickel-Cobalt Hydroxide Precipitate Using Organic Acids

“…For example, the precipitation of Co (IV) oxide from a synthetic cobalt-citrate complex in alkaline conditions using sodium lauryl sulfate (SDS) and in a protracted procedure is possible [21]. Solven extraction to achieve a selective separation of nickel, cobalt, and manganese from the citrate leach solution as suggested by the literature should be investigated for the MHP citrate system [22][23][24][25]. It is postulated that the inefficiency in achieving selective leaching is due to the possibility that the metal and citrate ions create a strong bond in the solution; hence, the selective separation of Co and Mn is challenging.…”

“…For example, the precipitation of Co (IV) oxide from a synthetic cobalt-citrate complex in alkaline conditions using sodium lauryl sulfate (SDS) and in a protracted procedure is possible [21]. Solven extraction to achieve a selective separation of nickel, cobalt, and manganese from the citrate leach solution as suggested by the literature should be investigated for the MHP citrate system [22][23][24][25].…”

Comprehensive Review on Concept and Recycling Evolution of Lithium-Ion Batteries (LIBs)

“…Citric acid is an excellent acid for selective metal dissolution compared to sulfuric acid. Ma et al observed from the experiment they conducted on spent LIBs that the citric acid with reducing agent H 2 O 2 shows a significant Co and Ni metal leaching process but slows dissolution of other metals such as Mn, Fe, and Zn. Musariri et al studied a 1–1.5 M citric acid solution for the leaching process to recover lithium, cobalt, and nickel from LIBs.…”