¿Por qué es necesaria la flotación de casiterita?

Resumen

Tin mining primarily relies on cassiterite (SnO₂), which accounts for most industrial tin production. While separación gravimétrica is the dominant beneficiation method due to cassiterite’s high density (6.4–7.1 g/cm³), its brittle nature leads to significant slime formation during crushing and grinding. Consequently, flotación becomes essential for recovering fine-grained cassiterite from re-election tailings and slimes. This article explores cassiterite flotation techniques, including optimal collectors, pH control, and environmental considerations in modern practices.

The Necessity of Cassiterite Flotation

Challenges in Cassiterite Beneficiation

• Natural Brittleness – Cassiterite readily forms slimes (<0.04 mm) during mining and processing, rendering gravity separation inefficient for fine particles.
• Complex Ore Compositions – Tin ores often contain sulfide minerals (e.g., pyrrhotite, arsenopyrite) and silicate gangue, requiring selective separation.
• Economic & Environmental Drivers – Flotation recovers tin from low-grade tailings (0.3–1.5% Sn), reducing waste and improving resource utilization.

Key Flotation Parameters

1. Collectors

Various fatty acids and their soaps easily capture cassiterite. Therefore, collectors can use oleic acid, tar oil, oxidized white wax soap, nylon 1010 bottom, alkyl sulfate, alkyl sulfonate, sulfosuccinate, etc. Experimental studies have shown that cassiterite flotation with formazan, benzylic acid, and ethylene sometimes yields better results.

2. pH Optimization

• Ácido oleico: el valor del pH suele estar en torno a 9,0~9,5.
• A: The pH value of the rough selection is generally 5~6, and it can reduce the pH value of the selected one to 2.5~4.0.
• When adjusting the pH of pulp, chemicals such as sodium carbonate and sulfuric acid are often used.
• During cassiterite flotation, to suppress the associated silicate ore, calcium magnesium ore, and wolframite, water glass, sodium hexametaphosphate, carboxymethyl cellulose, and oxalic acid.

3. Feed Preparation

• Pre-remove ultrafines (<0.01 mm) to reduce reagent consumption. The flotation material is generally gravity tailings less than 0.04mm, and the sludge less than 0.01mm is removed first.
• Desulfurize sulfide-rich ores antes de tin flotation to avoid concentrate contamination. If the flotation ore is vein tin ore, it is often accompanied by sulfide deposits of iron, arsenic, antimony, lead, copper, zinc, and other metals. At this moment, it should first use the sulfide deposit activator to separate the sulfide deposit. Then, flotation of cassiterite to avoid sulfide contamination of the cassiterite concentrate.

Planta de flotación de casiterita

The raw ore of tin ore is a high and medium-temperature hydrothermal cassiterite sulfide deposit. The composition of mineral deposits is messy. Metal deposits include pyrrhotite, magnetite, arsenopyrite, bismuthite, galena, sphalerite, chalcopyrite, etc. Non-metal deposits include carbonate, silicic acid, etc., salts, and halides. Cassiterite is yellowish-brown and black and is embedded in fine particles. Most of it is embedded in pyrrhotite in powder form, and a small part is scattered in magnetite and skarn deposits in granular form. The largest grain is 0.55mm, and the smallest is 0.002mm, generally between 0.15~0.02mm.

The feed of cassiterite flotation is the tailings after desulfurization, iron removal, and shaking table processing. The tailings of the mesa vibrante entrar en el espesador para la deshidratación y pasar al centrifugadora. El concentrado centrifugado se evacua por el espesante y luego se introduce en el tanque de mezcla para añadir medicamentos y pulpa. Utiliza ácido salicílico como colector, carbonato sódico para ajustar el pH de la pulpa a 7~8, goma de morera como depresor y aceite nº 2 como agente espumante. Seleccionar el concentrado de estaño mediante el primer barrido grueso, el segundo barrido, el tercer barrido fino y el primer barrido fino. El mineral bruto contiene 1,0% 6~1,3% de estaño, la ley del concentrado de flotación es de 1,3%~16%, y la tasa de recuperación es de 72%~76%.

The practice has shown that low-toxic salicylic enteric acid can completely replace the highly toxic swollen acid, significantly reducing the environmental pollution problems in the production and use of pharmaceuticals.

The flotation function for tin extraction from tin sludge and smelting slag: it has excellent collection and selectivity. It can replace the traditional medicament benzyl swollen acid for tin selection, overcoming the defects of benzylic swollen acid, such as preciousness and high toxicity.

Dosis propuesta: 400-800 g/tonelada de alimentación
El método de fabricación es a 2-5% aqueous solution (weight ratio), dissolved with 40C warm water.
Ámbito de aplicación: Lodos y escorias de fundición de estaño de baja calidad, que pueden hacer 1,5% de estaño a temperatura ambiente (temperatura mínima 5°C) para seleccionar más de 40% de polvo de concentrado de estaño, con una tasa de recuperación de más de 70%.
Función de protección del medio ambiente: El agente es poco tóxico, respetuoso con las personas y el medio ambiente y fácil de biodegradar.

Características del producto

1. Propiedades: El producto es un sólido pulverulento de color rosa a rojo anaranjado, ligeramente soluble en agua, fácilmente soluble en solución alcalina y estable.
2. New agent for selection efficiency.
3. La norma farmacéutica es sencilla, y el coste, bajo;
4. Respetuoso con el medio ambiente.

En determinadas condiciones, los colectores combinados presentan una buena selectividad. Este producto puede formar quelatos estables con estaño, tungstenotierras raras, cobre, hierro, and other metals. And it forms unstable chelates with alkaline earth metals and alkali metals. Therefore, the combination drug used in the flotation operation of some metal deposits can get a good separation effect. A combination of medications with flotation weight can achieve a very excellent result. Generally, the total recovery can reach more than 85%.

Conclusión

Cassiterite flotation is indispensable for maximizing tin recovery from fine-grained or complex ores where gravity methods fail. Advances in collector chemistry (e.g., eco-friendly chelating agents) and process optimization have made flotation both economically viable and environmentally sustainable. Future developments may focus on AI-driven reagent dosing and hybrid gravity-flotation circuits to further enhance efficiency.

Key Takeaway: Flotation transforms marginal tin resources into profitable reserves while mitigating mining’s ecological footprint.