Technical noteA new industrial mineral: Huntite and its recovery
Introduction
Huntite is one of the most important flame retardant additives, when it is used together with hydromagnesite. This type of flame retardant materials has been in the market since the late 1980s (Schmidt, 1999; Kirschbaum, 2001).
The most important huntite deposits available in the literature are located in Kozani Basin, Greece and Currant Creek deposits, USA. But the only commercial huntite deposit is located in Kozani Basin, Greece (Griffiths, 1985, Skillen, 1993). In Kozani, huntite which is mainly mined for flame retardant industry is produced purely with hydromagnesite. But, it occurs with various carbonate based minerals in different deposits.
Although there are many researchers studying various carbonate minerals, there are no enough detailed investigations about huntite processing and its selective separation from other carbonates in the literature. As it is well known, most carbonate based minerals have shown similar recovery characteristics due to the same chemical structures and compositions. Therefore, it is mostly difficult to separate these minerals from each other by flotation without modifying reagents.
The separation mechanism of carbonate minerals has been studied. Matis and Gallios investigated the mechanisms of various modifying reagents in the magnesite and dolomite system. They reported that sodium pyrophosphate, sodium hexametaphosphate and carboxymethyl cellulose had strong depression effect on dolomite while magnesite was little affected (Gallios and Matis, 1989, Matis et al., 1989). Kangal et al., 2004a, Kangal et al., 2004b investigated the flotation behaviour and physicochemical properties of huntite in the presence of anionic collectors. They reported that carboxymethyl cellulose acted a modifying reagent and strongly depressed huntite in the presence of potassium oleate.
In this study, characterization of huntite ores was made and flotation conditions for separation of huntite from the accompanying mineral, magnesite were investigated.
Section snippets
Material and methods
The pure huntite and run of mine huntite samples were taken from south-western part of Turkey.
Microflotation experiments
Microflotation experiments were performed by using a hallimond tube flotation cell of 170-ml. One gram of sample was conditioned in solution containing the given amount of collector for 5 min then floated for 2 min using nitrogen gas at a rate of 8 cm3/min. Microflotation experiments were conducted using 200 mg/l of KOl as collector and MgCl2, CaCl2, Na2SiO3 · 5H2O and CMC as modifying reagents. Because of the frothing properties of potassium oleate, no further addition was made.
Experimental findings
Conclusions
- 1.
The mineralogical investigations show that the main minerals are huntite and magnesite, serpentine, talc, dolomite, sepiolite with clay minerals as secondary minerals.
- 2.
The total weight loss of the huntite sample is 31.3% and 13.4% at temperature ranging from 400–600 °C and 600–850 °C, respectively. Dehydration was observed at 75 °C. At temperatures of 602.1 and 622.1 °C, two-staged decomposition occurred. The second decomposition was observed at 829 °C.
- 3.
Zeta potential tests performed with various
References (9)
- Dixit, A.S., Owens Jr., W.F., 1993. Reduced sidestream smoke smoking article wrappers, methods of making such wrappers...
- et al.
Floatability of magnesium carbonates by sodium oleate in the presence of modifiers
Separation Science and Technology
(1989) Huntite—a marketable product
Industrial Minerals
(1985)- et al.
Flotation behaviour of huntite, (Mg3Ca(CO3)4) with anionic collectors
International Journal of Mineral Processing
(2004)