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Selective flotation of witherite from calcite using potassium chromate as a depressant

Qiu Yangshuai, Zhang Lingyan, Jiao Xuan, Guan Junfang, Li Ye, Qian Yupeng

Physicochemical Problems of Mineral Processing

2019

Vol. 55, iss. 2

565--574

Witherite has been widely used as an industrial and environmental source of barium, with calcite being the primary associated carbonate mineral. However, few studies have been conducted to effectively concentrate witherite from barium ores. In this work, with the treatment of potassium chromate (K2CrO4) and sodium oleate (NaOL), witherite was selectively separated from calcite through selective flotation at different pH conditions. In addition, contact angle, Zeta potential, adsorption and X-ray photoelectron spectroscopy measurements were performed to characterize the separation mechanisms. The results demonstrated that NaOL had a strong collecting ability for both witherite and calcite; nevertheless, witherite could be effectively selected from calcite with the highest recovery at pH 9 in the presence of K2CrO4. From the XPS measurements, NaOL and K2CrO4 were found to be primarily attached to the surfaces of witherite and calcite through chemisorption. The presence of K2CrO4 on the surface of calcite adversely influenced the NaOL adsorption, which could make the flotation separation efficient and successful.

The effect of polyacrylic acid on the surface properties of calcite and fluorite aiming at their selective flotation

Zhang C., Gao Z., Hu Y., Sun W., Tang H., Yin Z., He J., Guan Q., Zhu Y.

Physicochemical Problems of Mineral Processing

2018

Vol. 54, iss. 3

868--877

In this study, the polyacrylic acid (PAA) was studied as a selective depressant for calcite in the selective flotation of fluorite and calcite, and the implications of this process for the separation of fluorite ore were studied using micro-flotation tests, and the results were analyzed with Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses. The flotation tests indicated that the preferential adsorption of PAA onto calcite rather than sodium oleate (NaOl) could selectively depress the flotation of calcite, allowing its separation from fluorite at pH 7. The zeta potential of calcite became more negative with the addition of PAA rather than with NaOl. However, the characteristic features of PAA adsorption were not observed for fluorite, suggesting that NaOl preferentially adsorbed on the surface of fluorite, or that PAA could be replaced by NaOl on the fluorite surface. FT-IR and XPS analysis were utilized to obtain a better understanding of the mechanism by which PAA was more strongly adsorbed on the calcite surface than NaOl. This was revealed to occur through chemical bonding between the carboxyl group of PAA and the hydroxyl groups of the Ca species on the calcite surface, modifying the structure of the adsorbed layer. A possible adsorption mechanism, along with a postulated adsorption mode for the surface interaction between PAA and calcite, is proposed.

Probable mechanism of the operation of the flotation pulp density on the selective flotation of the sulphide minerals

Petrova H., Boteva A.

Górnictwo i Geoinżynieria

2006

R. 30, z. 3/1

295-299

In this report it's looked through the problem about the research of the possibilities, by the change of the solid phase content in the pulp for improvement of the flotation process selectivity during the flotation of the multicomponent ores. It's searched for the relation between the lessened aeration in the conditions of the flotation with higher density of the flotation pulp and the competitive struggle between the main sulphide minerals which differ theirselves of it's hydrophobic mineral surface and of the processes, running in the three-phased froth as well. The results of the research indicate that the increased density doesn't always lead to the decrease of the process of selectivity. It's found that the rising of the solid phase content in the pulp up to a definite limit improves the selectivity of the process, but it can hardly get worse above this limit. The limit is most likely to be different for the different technological cases, but it's obviously to be always available.

Artykuł ten przedstawia problem badania możliwości, poprzez zmianę zawartości fazy stałej w mętach, poprawy selektywności procesu flotacji podczas flotacji wieloskładnikowych rud. Poszukiwano relacji pomiędzy zmniejszeniem aeracji w warunkach flotacji większej gęstości mętów flotacyjnych, różnicowanie pomiędzy głównymi minerałami siarczkowymi, co do ich hydrofobowości powierzchni oraz procesami przeprowadzanymi w trójfazowej pianie. Wyniki badań wskazują, że zwiększana gęstość nie zawsze prowadzi do obniżenia selektywności procesu. Stwierdzono, że zwiększenie fazy stałej w mętach do pewnej granicy zwiększa selektywność procesu, a może ją pogorszyć powyżej tej granicy. Granica zazwyczaj jest różna dla różnych przypadków technologicznych, ale jest zawsze możliwa do określenia.