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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
Figure 8.11 is the flow diagram for the Boliden sulfide-lime process that is being used to remove copper, lead, zinc, arsenic, and mercury that come from process water sources and cleanup sources. Sodium sulfide (Na2S) is used to precipitate the metals. The wastewater also contains fluoride, which is an anion and therefore does not react with sulfide. Sodium hydroxide (NaOH) is used to control the pH, so there are no safety or odor problems. The metal precipitates are removed by settling, with the aid of a polymer coagulant. Lime is added in a second stage of treatment to precipitate the fluoride as CaF2. The metal sludge and the fluoride sludge are combined for dewatering.
Froth flotation
Published in D.V. Subba Rao, Mineral Beneficiation, 2011
Sodium sulphide is used to activate oxide minerals of lead, zinc and copper such as cerussite, smithsonite and malachite. As sodium sulphide imparts sulphide surface to the mineral particles to facilitate for collector coating, this activator is also known as sulphidizer. Sodium sulphide is also used to float previously depressed pyrite. It has dispersing and depressing effects on sulphide minerals when added in large quantities.
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].
A review: can waste wool keratin be regenerated as a novel textile fibre via the reduction method?
Published in The Journal of The Textile Institute, 2022
The sequence of equations below show the reaction of sodium sulfide and keratin in a mixed solvent system, adapted from Poole, Church and Huson (Poole et al., 2009). The two free thiol groups that are formed, which are attached to the keratin chains, can form a new disulfide cross-link when the keratin is regenerated (Poole et al., 2009) (Equation 3).Dissociation of sodium sulfide in water Two consecutive nucleophilic displacement reactions, a and b, of keratin with (excess) thiol New disulfide cross-link
Changes in the composition of heavy oil during thermolysis in the presence of molten sodium without hydrogen
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Igor P. Kosachev, Dmitry N. Borisov, Dmitry V. Milordov, Nikolay A. Mironov, Svetlana G. Yakubova, Makhmut R. Yakubov, Airat I. Shamsullin, Tagir S. Aynullov
The composition and properties of the initial oil and its thermolysis products were analyzed. The density and kinematic viscosity were determined. The gas fraction was determined according to the weight difference of heavy oil before and after thermolysis. Coke was separated via filtration through the porous glass filter Schott. The precipitate was transferred to a flask, washed with isopropyl alcohol to remove sodium residues and, then, hydrochloric acid. The latter procedure was aimed at the qualitative determination of sodium sulfide, whose reaction with acids gives hydrogen sulfide. Hydrogen sulfide was detected both organoleptically according to rotten-egg odor and by the darkening of the filter paper soaked by lead (II) acetate solution according to the following reaction: