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Precipitation Reactions
Published in Paul Mac Berthouex, Linfield C. Brown, Chemical Processes for Pollution Prevention and Control, 2017
Paul Mac Berthouex, Linfield C. Brown
Sulfide precipitation is practiced in two forms. The soluble sulfide process (SSP) uses a water-soluble sulfide compound like sodium hydrosulfide (NaHS). The insoluble sulfide process (ISP) uses a slurry of slightly soluble ferrous sulfide (FeS), which will dissociate to satisfy its solubility product to yield a dissolved sulfide concentration of approximately 0.02 parts per billion in the wastewater. The flowsheets of the sulfide processes are compared with hydroxide precipitation in Figure 8.10.
Concentrating challenges of the Zarigan complex Pb-Zn-Fe non-sulfide ore
Published in Canadian Metallurgical Quarterly, 2023
Abdolmotaleb Hajati, Faraz Soltani
In general, sulfide minerals are easily concentrated by flotation, but flotation of oxide minerals is difficult due to their extensive surface hydration [3]. Another reason for the difficulty of flotation of lead oxide minerals is the difficulty in choosing a specific collector for each mineral [2] and the lack of proper response of these minerals to the xanthate collector as the most economical collector in the flotation process [1]. For these reasons, in the flotation of lead oxide minerals, the sulfidation-flotation technique is often used [4, 5]. In the sulfidation process using sodium sulfide or sodium hydrosulfide, sulfur is adsorbed on the surface of non-sulfide minerals. The low reactivity of sulfur with hydrogen increases the hydrophobicity of the mineral. In these conditions, the mineral absorbs xanthate more easily [1, 6]. Fuerstenau et al. (1985b) and Herrera-Urbina et al. (1999) showed that collector consumption in the flotation of anglesite and cerusite is several times higher than that of galena [7, 8]. It has been stated that the sulfidation process reduces collector consumption [9]. The most important parameters in the sulfidation of lead oxide minerals are the amount of sulfidation agent and the number of sodium sulfide addition stages [5].
The effect of grinding circuit efficiency on the grade and recovery of copper and molybdenum concentrates
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Ataallah Bahrami, Fatemeh Kazemi, Morteza Abdollahi, MirSaleh Mirmohammadi, Abolfazl Danesh, Yousef Ghorbani
B) Copper and molybdenum concentrate thickeners (code T-B and T-D): According to the flowsheet presented in Figure 1, by conducting flotation operation on the input load to the circuit (T-A thickener underflow), the resulted tailings from the flotation circuit will be transferred to tailings thickener (T-B copper concentrate) and the concentrate product is directed to the molybdenum concentrate thickener (T-D). In copper and molybdenum concentrate thickeners, the underflow of thickeners after filtering are considered as final products. The overflow of these thickeners is used as return water in the molybdenum flotation circuit. The overflow of these thickeners contains the chemicals used in the molybdenum flotation circuit, including diesel (collector for molybdenite), sodium hydrosulfide, sodium cyanide, and ammonium sulfide (copper mineral depressant), and EXfome 636 (frother); which is utilized as a return in the circuit. Reuse of the mentioned chemicals in the overflow of concentrate thickeners will reduce the consumption of chemicals and as a result, it will be economical, as well as prevent their entry into the environment and its subsequent pollution.
Depression Mechanism of Sodium Sulfide in Flotation Separation of Molybdenite and Bismuthinite
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Runqing Liu, Chongyi Zhong, Shangyong Lin, Dongdong He, Wei Sun
Up to now, many depressants have been developed for depressing other sulfides during molybdenite flotation (Das, Briceno and Chander 1992), such as sodium sulfide (Na2S) (Ansari and Pawlik 2007), sodium hydrosulfide (NaHS) (Bulatovic and Srdjan 2007), hydrogen peroxide (Suyantara et al. 2018), n-dodecane (Bakalarz, Gloy and Luszczkiewicz 2015), pyrogallic acid (Lin et al. 2019), dextrin (Braga et al. 2014), or their combinations (Wang et al. 2020). Among them, Na2S is the conventional and widely adopted inorganic depressant in the industry to depress bismuthinite. The main disadvantage of Na2S is the production of harmful gas, sulfur dioxide (SO2), which may result in environmental pollution. Organic depressant like dextrin was environmentally friendly and economic (Cruz et al. 2021). However, their poor selectivity and adaptability hinder their further application in the industry (Liu and Liu 2004; Qin et al. 2017). Combined inhibitors provide a novel idea for separating molybdenite from Mo–Bi bulk concentrates (Wang et al. 2020). Nonetheless, they have many drawbacks, such as complicated process, low efficiency, and uneconomic production, which impede their extensive application in the industry (Liu et al. 2020). Therefore, the traditional depressant Na2S, as the most effective bismuthinite depressant, would not be replaced in the short term in industrial production and will be utilized in the flotation separation of molybdenite and bismuthinite for a long time.