Solubility of flotation reagents in water and methods for its increase

Abstract

The low solubility of reagents in water (flotation pulp) causes technical and technological complications (high reagent consumptions, necessity for preheating the pulp and emulsifying the reagent, its effect on froth formarion, etc.).The form in which the reagent is introduced imo the pulp has an important effect on its reaction with the mineral particles, which largely determines the results of the flotation process as a whole. The solubility of the reagent in water may be markedly changed by a cor~roUed change in its flotation properties by introducing cha.,'-acteristic atomic groups and various sub~ituer~ [I, 2]. Thusthe factom governing the solubility of a reagent in water, and methods for increasing the solubiUty of reagents, are of practical interest for flotation.Water is a high-polar solvent which is highly associated owing to formation of hydrogen bonds (H bonds) between its molecules. Organic substances the molecules of which are relatively small such as ethers, aldehydes, amines, carboxylic acids and ketones, dissolve in water largely owing to formation of H bonds [3,4]. The electronegative atoms between which H bonds are formed are usually oxygen, nitrogen, or fluorine, and in certain cases chlorine. This relates to syltems in which the presence of H bonds is well known.However, it is assumed that the condition of high eleotronegativity of the atoms is not obligatory for formation of a hydrogen bond [3]. Acids which form H bonds include halogen--activated C-H groups, acetylene groups C = H, and SH groups (haingen=sub~itnted thiophenols dithiophosphoric acids [5], etc.).Proof of the capacity of the sulfur atom to act as a base for formation of an H bond has been obtained for ethylene thiourea Nitrogen forms'hydrogen bonds only slightly weaker than oxygen bonds. Sulfur is far less effective in hydrogen-bond formation than oxygen; therefore,replacement of O by S in compounds of similar structure always greatly reduces their solubility in water. Thus the solubility (t = 20~ of urea is 108.3 g per 100 g of water, while that of thiourea is only 12.0 g [11].Aliphatic hydrocarbon chains and aromatic rings which cannot participate in such reations reduce the solubility of the substance in wate~ this effect being intensified with increasing lengthening of the chain or with in = troduction of a greater number of rings, As shown by Kakovskii ['12], the solubillty of a reagent in water is reduced by a factor of 4,3 with an increase in its length by one hydrocarbon chain (within the same homologous series). P~placement of the hydrogen atoms of aromatic rings by halogen atoms or nitro groups Sways reduces the solubility of a reagent in water. This must be borne in mind because in a number of cases the selectivity of a reagent may be heightened by introducing halogen atoms or nitro groups into its molecule without changing the length of its hydrocarbon radical (the number of aromatic tings).The solubility of an organic reagent in water may be increased in two ways.Giredmet, Moscow.

Adsorption of 2-(Hexadecanoylamino)Acetic Acid Onto the Surface of Smithsonite: Mechanism and Flotation Performance

“…Compared to zinc sulfide minerals, the main factor responsible for the low natural floatability of smithsonite is the high activity of water dipoles. This phenomenon decreases the probability of effective reagent adsorption on the smithsonite surface [13,14]. The chemistry of smithsonite dissolution and hydrolysis reactions As is evident from the above, the smithsonite surface is charged through non-stoichiometric dissolution and hydrolysis, with some ions released into the solution.…”

The Flotation Process Can Go Green

“…in ancient Greece, Herodotus (in Historiae, Book IV) was probably the first person to describe a process similar to flotation. This process was created in order to separate (using fatty substances) gold particles from sand [7]. Quite early also, application of this technique to wastewater treatment was reported [8].…”

Απομάκρυνση Χρωστικών Από Υδατικά Συστήματα Με Την Τεχνική Της Επίπλευσης

“…Τα αντιδραςτιρια τθσ επίπλευςθσ, ανάλογα με τθ δράςθ τουσ, ταξινομοφνται ςε τρεισ κφριεσ κατθγορίεσ: τουσ ςυλλζκτεσ, τα αωριςτικά μζςα και τουσ τροποποιθτζσ [Klassen and Mokrousov, 1963;Glembotskii et al, 1972].…”

“…Είναι ετεροπολικζσ ταςενεργζσ ενϊςεισ, που αποτελοφνται από δφο τμιματα που διαωζρουν ςτισ ιδιότθτζσ τουσ, το πολικό και το μθ πολικό τμιμα. Το μθ πολικό μζροσ του μορίου είναι ςυνικωσ μια ευκεία ι διακλαδιςμζνθ υδρογονανκρακικι ι ωκορανκρακικι αλυςίδα με μικοσ 8 -18 άτομα άνκρακα, που δεν αλλθλεπιδρά με το νερό (υδρόωοβο τμιμα), ενϊ το πολικό μζροσ του μορίου είναι μία ιονικι ι ουδζτερθ, ανόργανθ ι οργανικι ομάδα που αλλθλεπιδρά με το νερό (υδρόωιλο τμιμα) [Klassen and Mokrousov, 1963;Glembotskii et al, 1972]. Οι γενικζσ ιδιότθτεσ και θ ςυμπεριωορά αυτϊν των ουςιϊν οωείλονται ςτθ διττι ωφςθ του μορίου τουσ.…”

“…Ζτςι το ςωματίδιο καλφπτεται με μια υδρόωοβθ ςτιβάδα. Οι ςυλλζκτεσ, δθλαδι, λειτουργοφν ςα γζωυρα μεταξφ των ςωματιδίων και τθσ ωυςαλίδασ [Klassen and Mokrousov, 1963;Glembotskii et al, 1972].…”