Microanalysis of Flotation Reagents and Adsorption Measurement

Microanalysis of flotation reagent is an important instrumentality for controlling flotation process, as well as researching flotation theory. In general, reagent concentration is 10−7 to 10−3 mol/L in ore pulp. In addition, some interference factors also

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Microanalysis of Flotation Reagents and Adsorption Measurement

Microanalysis of flotation reagent is an important instrumentality for controlling flotation process, as well as researching flotation theory. In general, reagent concentration is 10−7 to 10−3 mol/L in ore pulp. In addition, some interference factors also exist in the adsorption of organic reagent. Therefore, some special methods must be adopted for the analysis of minute amounts of flotation reagents.

6.1 6.1.1

Principle of Microanalysis of Flotation Reagents Physical and Instrumental Analysis

(1) Surface tension method Surface tension of compound varies with solution concentration. The relations between surface tension and solution concentration are presented in Fig. 6.1. Collectors and frothers are usually heteropolar organics. And some of them are typical surfactants. As discussed in Chap. 4 (Volume 1), the relations between surface tension and solution concentration of surfactant can be described by the following formula:   r0  ar C ¼ b ln 1 þ r0 a where σ0 refers to the surface tension of water; σ refers to the surface tension of surfactant solution; C refers to the surfactant solution concentration; a refers to the constant which is concerned with nonpolar groups of surfactant; b refers to the constant which is concerned with polar groups of surfactant.

© Metallurgical Industry Press, Beijing and Springer Science+Business Media Singapore 2016 D. Wang, Flotation Reagents: Applied Surface Chemistry on Minerals Flotation and Energy Resources Beneficiation, DOI 10.1007/978-981-10-2027-8_6

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6 Microanalysis of Flotation Reagents and Adsorption Measurement

σ

154

C Fig. 6.1 Relations between surface tension and solution concentration

In general, the change of surface tension is proportional to the solution concentration at low reagent concentration: Dr ¼ r0  r ¼ aC According to the report of Malati [1], the surface tensions of frother and sulfhydryl collector change slightly with the solution concentration at low reagent concentration. The change of surface tension is proportional to the solution concentration of oxide collector with long hydrocarbon chain. Therefore, surface tension can be used to research the adsorption amount of reagent on mineral surface. However, the testing course of surface tension must be rigorous because solution pH influences the surface tension obviously. (2) Potentiometric, conductometric, and amperometric titration Potentiometric titration is based on the relation between electrode potential of ion and solution concentration of surfactant: E ¼ E0 þ

1 0:0591pM n þ n

where E refers to electrode potential; E0 refers to standard electrode potential; M refers to the concentration of metal ion; P refers to the negative logarithm; n refers to valence number of metal ion. When the metal ion is titrated with reagent, electrode potential of ion suddenly jumps at the endpoint of the titration. Conductometric titration is used to the change

6.1 Principle of Microanalysis of Flotation Reagents

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of solution elec