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In general, the dosage of xanthate ester is 2–15 g/t. It will have frothing capability when the dosage of xanthate ester is too large. (6) Xanthate ester can be used to the flotation separation of blende pyrite and towanite pyrite. Meantime, xanthate ester performs good selectivity. As mentioned in Chap. 8 Thionocarbamates The general expression of thionocarbamates can be given by the following: S R NH C S R' Thionocarbamates can be considered as that the —SH of alkyl dithiocarbamic acids (RNHCSSH) is substituted by —OR′.

Glembotski, thiocarbamate adsorbs on towanite and molybdenite via chemical adsorption. And the chemical adsorption between thiocarbamate and towanite is obvious at pH*8. But chemical adsorption cannot take place between thiocarbamate and pyrite. Compared with thiocarbamate, there exists chemical adsorption occurring between xanthate and the above minerals. And the chemical adsorption of xanthate weakens with increasing the pulp pH. 8 Thionocarbamates 45 (1) Carbamothioates 1) One of structural expressions of carbamothioates can be expressed as follows: R X R1 H S N C R2 O where R refers to the alkyl with C1–C10, H, alkynyl, aryl, or cycloalkyl; R1 refers to the unsaturated hydrocarbon radical with C1–C7; R2 refers to the saturated hydrocarbon radical with C1–C7 or cycloalkyl; X refers to —O—, —S—, ═S═, O═S═O.

Recovery rate (%) 1—sodium diethyldithiocarbamate 2—diphenylguanidine 3—phenyl thioacetamide C (mg/L) Fig. 3 29 S-Substituted Thiocarbamides (1) Preparation of S-substituted thiocarbamides 1) The reaction of thiocarbamide and haloalkanes S-substituted thiocarbamides can be produced by the following reaction: NH2 NH2 S +RX C R S C NH2 X NH2 where X refers to halogen. The detailed synthetic steps can be found from related documents [10–12]. 2) The reaction of thiocarbamide and esters S-substituted thiocarbamides can be prepared from thiocarbamide and esters.