The flotation mechanism of aluminosilicate minerals using alkylguanidine collectors was studied through flotation experiments, Zeta potential measurements and FT-IR spectrum analysis. It is shown that kaolinite, illite and pyrophyllite all exhibit good floatability with alkylguanidines as collectors at pH 4-12. The flotation recoveries rise with the increase of the carbon chain length. Isoelectric point(IEP) is determined to be 3.5, 3.0 and 2.3 for kaolinite, illite and pyrophyllite, respectively. However, it is anomalous that the presence of cationic collectors has less influence on the negatively charged mineral surfaces. It is explained by the special structure of guanidine which is one of the strongest bases, having two -NH2 groups. One of them maybe interacts with minerals by electrostatic forces, and the other maybe forms hydrogen bonding with OH- ions on the aluminosilicate surfaces or in the aqueous solution, increasing the density of negative charge on the aluminosilicate surface and leading unpronounced positive charge to increase on the aluminosilicate. By combining the flotation tests, Zeta potential and FTIR measurements above, the interaction mechanism can be concluded. The simultaneous presence of cationic and neutral amine groups makes it possible for SAG cation to bind on three aluminosilicate minerals by both electrostatic attraction and hydrogen bonding. While in acidic medium, the interaction of the alkylguanidines on the aluminosilicate surfaces is mainly by means of electrostatic force and hydrogen bond; in the alkaline medium, it is by the way of electrostatic effect and hydrogen bond.

The effect of cationic groups on performance of 12-carbon chain collectors in flotation separation of diaspore from kaolinite, pyrophyllite and illite has been investigated by flotation tests and explained by density functional computations. The flotation test results indicated that the separation of diaspore from these aluminosilicate minerals was feasible at strong alkaline conditions by using cationic collectors, dodecylamine chloride (DDAC), dodecyl trimethyl ammonium chloride (DTAC) or dodecylguanidine sulfate (DDGS), respectively. In strong alkaline conditions, these three collectors showed excellent selectivity against diaspore, however, DDGS returned superior collecting ability for aluminosilicate minerals compared with DDAC and DTAC. By using the density functional theory (DFT), we calculated some properties such as the H and N atomic charges and cationic group charges which are related to the reactive behavior of 12-carbon chain collectors at B3LYP/6-31G (D) level. The results of calculations indicated that the efficiencies of these three cationic collectors depend on the investigated parameters, and DDGS is better than DDAC and DTAC as a collector agent. The theoretically obtained results are consistent with the flotation tests.

Alkylguanidine was an important cationic surfactant with alkalescence,stability and biological activities.It had been widely applied in medicine,agriculture,chemistry and other industry.The application of alkylguanidine served as bactericide and catalyzer was introduced.The synthesis methods of alkylguanidine were briefly reviewed.Some proposals on alkylguanidine's development were put forward.

The electrokinetic properties and flotation of diaspore, kaolinite, pyrophyllite and illite with quaternary ammonium salts collectors were studied. The results of flotation tests show that the collecting ability of quaternary ammonium salts for the four minerals is in the order (from strong to weak) of octadecyl dimethyl benzyl ammonium chloride(ODBA), cetyl trimethyl ammonium bromide(CTAB), dodecyl trimethyl ammonium chloride(DTAC). Under the condition of alkalescence, it is possible to separate the diaspore from the silicate minerals such as kaolinite, illite and pyrophyllite using quaternary ammonium salts as collector. Isoelectric points (IEP) of diaspore, kaolinite, pyrophyllite and illite are pH=6.0, 3.4, 2.3 and 3.2, respectively. Quaternary ammonium salts can change ζ-potential of the aluminosilicate minerals obviously. The flotation mechanisms were explained by ζ-potential and Fourier transform infrared spectrum (FT-IR) measurements. The results demonstrate that only electrostatic interaction takes place between aluminosilicate minerals (diaspore, kaolinite, pyrophyllite and illite) and quaternary ammonium salts.

The flotation behavior and mechanism of three quaternary ammonium salt collectors including dodecyl trimethyl ammonium chloride,hexadecyl trimethyl ammonium bromide and octadecyl dimethyl benzyl ammonium chloride for aluminosilicate minerals such as diaspore,kaolinite,pyrophyllite and illite were studied by single mineral tests,electrokinetic potential measurement and infrared spectral analysis.The results show that in alkaline medium,the separation of diaspore from the other three silicate minerals by reverse flotation can be realized by using quaternary ammonium salts as collectors;the isoelectric points of diaspore,kaolinite,pyrophyllite and illite are at pH 6.0,3.4,2.3 and 3.2 respectively and the electrokinetic potential on their surface will negatively increase with the pH increase;and it is mainly by static adsorption that quaternary ammonium salts are adsorbed on the surface on diaspore,kaolinite,pyrophyllite and illite.

The reverse flotation separation of kaolinite and diaspore has been achieved by using the collector dodecylamine (DDA) and depressant cationic polyacrylamide (CPAM) at pH 5.5–8.5. The flotation results have been explained by adsorption measurement, solution chemistry and density functional theory (DFT) calculations. At pH 5.5–8.5, the main components at the diaspore/water interface are AlOH2+, AlOH and AlO−. The AlOH2+ and AlOH sites can adsorb the C(O)NH2 groups through AlOH⋯O or AlOH2+⋯O hydrogen bonds. Simultaneously, the AlO− sites adsorb CH2N+(CH3)3 groups by electrostatic effects or adsorb C(O)NH2 group through the NH⋯−OAl hydrogen bond. The absorption of CPAM on all the crystal planes of diaspore prevented the majority of DDA cationic species from adsorbing on the diaspore surface, and thus, depressed diaspore flotation. The adsorption ability of the CPAM cation group on the negatively charged sites on the kaolinite surface was weakened by the inductive and steric effect of methyl in CH2N+(CH3)3 groups, which made CPAM have a insignificant effect on the adsorption of DDA on the kaolinite surface and its cation flotation.

High polymer adsorbent is one of the important functional polymer materials.In this paper,the variety,performance as well as the structure of the high polymer adsorbent are briefly introduced.And the research progress of the adsorbent used in the water treatment,the medication,the machining,etc.is surveyed.

Guanidine compounds are widely applied in medicine,chemistry and other industry because of its strong alkalinity,high stability and good biological activities.The application and synthesis methods of guanidine compounds were discussed in details.Some proposals on guanidine compounds' development were put forward.