The chemical formula of coltan-niobite is AB2O6, which is referred to as coltan. A is iron and manganese , and B is strontium and barium. The magnetic susceptibility of the coltan-niobite is (22.1 to 37.2) × 10-6. The tantalum iron has a dielectric constant of 10 to 12 and the tantalite has a density of 7 to 8. The density of minerals is 5.15 to 8.20 (increased as the content of strontium increases).
At present, the beneficiation process of antimony ore in China mainly includes: rough selection, selection and flotation. Yankuang ore dressing generally adopts re-election to discard most of the gangue minerals and obtain low-grade mixed coarse concentrates. The coarse concentrate minerals entering the selected operations are complex in composition and generally contain a variety of useful minerals. A variety of beneficiation methods such as re-election, flotation, electromagnetic selection or combined metallurgy are selected to achieve separation of a variety of useful minerals.
The ore grade of domestic antimony ore is generally low, and its minerality is brittle and dense. In order to ensure the grinding particle size and avoid over-grinding, the rough selection generally adopts the stage grinding stage selection process. The re-election equipment includes a GL spiral concentrator, a spiral chute and a shaker. The coarse concentrate obtained by the rough selection process is generally a mixed coarse concentrate, which needs to be further selected to separate a variety of useful minerals. The composition of the crude concentrate minerals is different, and the separation methods used are also different. Generally, a plurality of methods are used in combination. For example, a magnetic separation-reselection-flotation combination method is employed. The commonly used collectors for the flotation of antimony ore are fatty acids, tannins, phosphonic acids, hydroxamic acids, cationic collectors, etc. The environmental pollution of the collectors and the cost of the chemicals are of paramount importance.
With the development of more and more difficult resources, it is expected that the demand for selective and reasonably priced minerals will continue to increase. At the same time, due to the wide range of raw materials for the ore dressing agent, the synthesis process is simple, biodegradable, non-toxic and harmless, and the chemicals with good selectivity and reasonable price will continue to appear, which will meet the needs of the miners.
Research Status and Development of Floatation Chemicals in Sancha Mine
(1) 钽铌 mineral collector
The most effective collectors for antimony ore are fatty acids, tannins, phosphonic acids, hydroxamic acids, and cationic collectors.
1, the former Soviet fatty acids collector clopidogrel Grad Gehennas gold oxide ores have been used for two collector: oleic acid, sodium oleate, sodium tridecyl, sodium tallow alkyl sulfate, sodium phosphate and isooctyl A detailed study of the floatability of coltan-niobite. Tests have shown that when using fatty acids as collectors, the trapping ability of saturated hydrocarbon groups is worse than that of unsaturated ones. When the pH value is 6-8, the flotation of coltan-anthalite with sodium oleate is very effective, and it is inhibited in both strong acidic medium and strong alkaline medium. Modification of fatty acids can improve their selective capture. For example, a new effective reactive group sulfonic acid group, polycarboxyl group, sulfuric acid group, halogen, amine (amino) group, aminoacyl group, amide group and the like are introduced into the molecule.
2. The tannic acid collector citrate can form a strong surface compound with rare metal minerals such as strontium and barium. The hydrocarbon group is outward and the mineral is hydrophobic. However, this chemical adsorption does not exist with gangue minerals, so the collection ability is strong and the selectivity is good. The disadvantage is that there are pollution problems in the production and use of bismuth-containing substances. Benzyl phthalic acid and toluic acid are effective collectors for strontium minerals. The combination of citric acid and xanthate can greatly improve the recovery rate of strontium minerals.
3. The study of the use of bisphosphonic acid to collect ruthenium rutile by phosphonic acid collector shows that bisphosphonic acid is a good collector of ruthenium rutile when the pH value of the slurry is 2 to 4, and the recovery rate reaches 90.87%. ~91.70%, at the same time, it is believed that the bisphosphonic acid is adsorbed on the surface of the ruthenium rutile, and the adsorption form is mainly chemical adsorption.
4. Hydroxamic acid collectors The industrial hydroxamic acid used in some fine earth mines in China is equipped with transformer oil for rough selection. When the ore contains Nb2O5 0.094%, the crude concentrate grade Nb2O5 0.9~1.0 can be obtained. %, the recovery rate is about 90%.
5. Studies on cationic collectors show that laurylamine acetate can effectively float limonite minerals in neutral media.
6. Other collectors The use of the new agent N2 for the capture performance of strontium minerals shows that the high carbon chain N2 is an effective collector for strontium minerals. Good results were obtained by flotation of the Bayan Obo ore with N-nitrosophenylamine. The exploration experiments in the former Soviet Union showed that the hydrocarbyl sulfate was also suitable for the flotation of the coltan-tantalite in the pegmatite deposit.
Many flotation agents, especially collectors, are not ideal when used alone. However, when some agents are used in combination in a certain proportion, the effect is not a simple additive effect, but a synergistic effect, that is, 1 +1>2 synergy effect. Such as xanthate and hydroxamic acid combined flotation copper oxide; sodium oleate and hydroxamic acid combined flotation of andalusite ; tannic acid and xanthate mixed, copper iron spirit mixed with benzoic acid, benzoic acid and Tal soap is mixed and floated with black tungsten fine mud; F2O3 and salicyloxyphthalic acid mixed with flotation of cassiterite fine mud have achieved good results.
(2) Antimony ore flotation regulator
The main gangue minerals of antimony ore are silicate minerals, fluorite and carbonate minerals. Typical inhibitors of these minerals are water glass, sodium hexametaphosphate, starch, pyrophosphoric acid, sodium hydrogen phosphate, sodium lignosulfonate, tannin, lactic acid, citric acid, tartaric acid, and the like. The pH value has a great influence on the flotation process, and the modifiers commonly used for adjusting the pH value include sulfuric acid, hydrochloric acid, sodium hydroxide, and soda.
(III) Analysis of problems existing in antimony ore flotation
1. Collection of collectors. The molecule contains functional groups -COOH, -SO4H, -SO3H, which have strong collection ability and poor selectivity, and are only suitable for the fine mud with a simple flotation mineral composition and quartz as the main gangue. Hydroxamic acid has a weaker ability to absorb fine mud than fatty acids, but the choice is better. Phosphonic acid has a strong ability to capture antimony ore.
2. Environmental pollution of pesticides and cost of pharmaceuticals. Tannic acid can form a strong surface compound with metal ore such as strontium and barium. The hydrocarbon group is outward and makes the mineral hydrophobic. However, this chemical adsorption does not exist with gangue minerals, so the collection ability is strong and the selectivity is good. Ca2+ and Mg2+ ions are not sensitive and have strong adaptability to ores with high calcite . However, citrate is highly toxic and may cause environmental pollution. In the fine mud flotation, the dosage is large and the price is high. At the same time, some of the chemicals are more toxic and need to increase environmental protection costs, thereby increasing the cost of mineral processing. When using hydroxamic acid flotation, the effect is better, but the amount of the agent is larger.
In recent years, the domestic research on flotation flotation has made some progress. However, due to the high price of pharmaceuticals, only a few foreign mines have adopted flotation methods, such as the Canadian Oka Concentrator and the Brazilian Araksa Mine.
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