Abstract: The flotation separation behavior of rhodochrosite and quartz was studied， and the effect of sodium silicate and sodium hexametaphosphate on flotation separation of rhodochrosite and quartz was investigated in dodecylamine flotation system. The results show that dodecylamine has good collecting ability for rhodochrosite and quartz in pH range of 7~12. Meanwhile， sodium silicate and sodium hexametaphosphate can remarkably activate the flotation performance of rhodochrosite. Conversely， quartz is inhibited by sodium silicate and sodium hexametaphosphate. The flotation tests of mixed minerals show that it is difficult to achieve the flotation separation of rhodochrosite and quartz when sodium hexametaphosphate is used as modifier at pH 7. UV spectrophotometry tests show that electrostatic adsorption exists between Mn2+ and quartz at pH 7. The FTIR measurements indicate that sodium silicate can adsorb on the rhodochrosite and quartz surfaces， sodium hexametaphosphate can adsorb on the rhodochrosite surface.

Key words: rhodochrosite, quartz, flotation, dodecylamine, sodium silicate, sodium hexametaphosphate