Spodumene is an important lithium mineral resource. At present, the flotation method is widely used for spodumene with high frequency. The key point of flotation method is the selection of flotation reagents, which are mainly divided into collectors and regulators.
Spodumene flotation collectors mainly include single collectors, combined collectors and new collectors.
1. Single collector
Single collectors are mostly used for laboratory research. Spodumene flotation is currently mainly divided into two processes: reverse flotation cationic collectors and positive flotation anionic collectors. The common reverse flotation cationic collectors are amine collectors, and the common ones are dodecylamine. This kind of reagent can be used to select quartz, mica and other gangue minerals by reverse flotation in alkaline slurry. This method is mainly applicable to rough separation.
The anionic collectors of traditional positive flotation spodumene ore are mostly fatty acids and soap collectors, such as oleic acid, sodium oleate, naphthenic acid soap, oxidized paraffin soap, etc. The advantages of this kind of collector are wide range of use, low price, strong collection capacity, and the disadvantages are poor selectivity, temperature sensitivity, hard water resistance, and significant fluctuations in mineral processing indicators.
2. Combined collector
The use of combined collectors can usually play a synergetic role of multiple reagents to obtain ideal flotation separation indicators. A spodumene concentrate with Li2O grade of 6% and operation recovery of 62% was obtained by treating a spodumene ore in China with sodium oleate+oxidized paraffin soap as a combined collector. Under the condition of using oxidized paraffin soap+oximic acid as the combined collector, the raw ore with Li2O grade of 1.25% was flotation, and the concentrate with Li2O grade of 6.21% and recovery rate of 76.30% was obtained.
The use of combined collectors can significantly improve the mineral flotation separation effect, reduce the dosage of reagents, and significantly improve the economic benefits of enterprises.
3. New collector
In recent years, new efficient collectors for spodumene flotation have been emerging. At present, most of the high-efficient collectors for spodumene flotation developed are chelating collectors. Although they have good selectivity and excellent performance, they are generally expensive and difficult to popularize in practical production and application. Therefore, in the follow-up research and development of new collectors, we should not only pay attention to its high efficiency and adaptability, but also pay attention to its environmental friendliness, extensive sources and economy.
The flotation regulators of spodumene ore are mainly "three alkalis", namely Na2CO3, NaOH, Na2S and CaCl2.
1. Activation effect of modifier and metal ions
The hydroxyl complex formed by metal ions under neutral or weak alkaline conditions has high adsorption capacity, which can greatly improve the collection capacity of minerals and thus improve the flotation effect.
2. Effect of regulator and traditional inhibitor
When adding basic modifiers such as calcium chloride, sodium carbonate, sodium hydroxide, etc., the slime composed of silicate minerals in the pulp will react with alkali to form a certain amount of sodium silicate, which is itself an inorganic inhibitor, and has the same effect on flotation as adding traditional inhibitors. Therefore, inorganic inhibitors are not added intentionally in flotation practice.
3. Effect of regulator and new inhibitor
Among the new inhibitors, citric acid and lactic acid have weak selectivity for the inhibition of spodumene and beryl, tartaric acid and oxalic acid have strong inhibition but no selectivity for the two minerals, Na2S, sodium hexametaphosphate and disodium ethylenediamine tetraacetate have both strong inhibition and selectivity, among which disodium ethylenediamine tetraacetate has better selectivity for spodumene.
The difficulty in the flotation separation of spodumene ore is an important reason for the hindrance in the development of lithium resources at present. To create favorable conditions for the flotation separation of spodumene and gangue minerals, and to develop green and environment-friendly new reagents and efficient combination reagents according to the characteristics of the ore are important directions for the progress of spodumene ore flotation technology.
