Brown iron tungsten and tin containing iron recovery and separation technology: overcoming the complex co-associated ore resourceization problems

Abstract: During the beneficiation and smelting process of tungsten and tin ores, a large amount of tungsten- and tin-containing brown iron tailings or intermediates will be produced. This kind of material has complex composition and close coexistence of tungsten, iron and tin, which is a typical difficult resource to be processed. This paper analyzes the core technology of brown iron containing tungsten and tin recovery and separation technology, how to realize the efficient separation and comprehensive recovery of iron, tungsten and tin through the advanced technology route, turning waste into treasure and creating significant economic value.

Keywords: brown iron containing tungsten and tin iron recovery and separation technology, tungsten and tin recovery, limonite resource utilization, symbiotic ore beneficiation, separation of iron and tungsten, rare metal recovery

I. Resource Characteristics and Challenges: Why is it difficult to recover tungsten-tin ores of brown iron type?

Tungsten- and tin-containing limonite usually originates from the oxidized weathering zone of primary tungsten-tin ore or smelting slag, and its main characteristics determine the difficulty of recovery:

1. Complex mineral composition:Limonite (FeO-OH-nH₂O) is the main phase of the material, tungsten is usually dispersed in the form of scheelite (CaWO₄) or tungstate, and tin exists in the form of cassiterite (SnO₂). The three fine grain size, mutual package, embedded relationship is very close.

2. Similar physical properties: limonite, cassiterite and scheelite are weakly magnetic or non-magnetic minerals, and the specific gravity has a certain overlap (limonite ~ 4.0, cassiterite ~ 6.8, scheelite ~ 6.0), the separation efficiency of traditional re-election and magnetic separation is low.

3. Surface interference: Limonite surface is easy to sludge, strong adsorption, will seriously interfere with the selectivity of the subsequent flotation chemicals, resulting in poor sorting accuracy and low recovery.

Therefore, it is almost impossible to separate effectively by a single conventional beneficiation method, and we must rely on the innovative joint process.

II. Core Technology Route: Multi-technology Coupled Synergistic Separation Scheme

In response to the above challenges, successful separation technology for brown iron containing tungsten and tin usually follows the principle of "pre-enrichment - separation of iron, tungsten and tin - deep purification", and adopts the following core steps:

1. Pre-treatment and pre-enrichment stage:

• Crushing and grinding: Control the appropriate grinding fineness, the goal is to realize the full "dissociation" of tungsten, tin minerals and limonite, and at the same time to avoid over-grinding and sludging.

• Classification and desliming: Removal of very fine-grained slimes using equipment such as hydrocyclones. This step is crucial, can effectively remove the influence of subsequent sorting of fine particles and harmful impurities, greatly improving the sorting efficiency.

2. High-efficiency gravity separation pre-enrichment:

• Utilizing the specific gravity difference between tungsten, tin minerals and limonite, the spiral concentrator, shaking table and other high-efficiency gravity separation equipment are used for pre-enrichment.

• At this stage, some light specific gravity vein minerals can be thrown out, and a rough concentrate with enriched tungsten, tin and iron can be obtained, which can reduce the load for the subsequent fine separation.

3. Magnetic separation-roasting combined iron removal technology:

• Strong magnetic separation: Firstly, high gradient strong magnetic separator is used to take advantage of the difference between weak magnetism of limonite and tungsten and tin minerals (non-magnetic or weakly magnetic), initially separating out part of limonite and obtaining non-magnetic products mainly of tungsten and tin.

• Reduction Roasting - Magnetic Separation (key technology): This is the core of realizing the deep separation of iron, tungsten and tin.

  • Reduction Roasting: The re-election concentrate is roasted with a reducing agent (e.g. coal dust) at a specific temperature. Limonite is reduced to strongly magnetic magnetite (Fe₃O₄) or metallic iron.

  • Weak Magnetic Separation: After roasting, the material is subjected to weak magnetic separation to efficiently separate the magnetic iron minerals (magnetite/metallic iron) from the non-magnetic, stable cassiterite and scheelite. This step has high iron recovery rate and remarkable separation effect. 4.

4. Separation of tungsten and tin by flotation:

• After iron removal, the material is mainly a mixed concentrate of cassiterite and scheelite. Due to the difference of their floatability, flotation is the most efficient separation method.

• Cassiterite - scheelite separation flotation:

  • Usually, fatty acid-based trapping agent is used first to flotation scheelite under acidic condition and suppress cassiterite.

  • Alternatively, cassiterite is flown first, and then scheelite is flown under alkaline conditions using a special integrated trap.

  • Through the precise pharmaceutical system (adjuster, inhibitor, trap) and pH control, the separation of tungsten and tin with high efficiency and high purity can be realized.

5. Deep purification of products:

• The obtained tungsten concentrate (scheelite) and tin concentrate (cassiterite) can be further refined by acid leaching, roasting or electrowinning according to the market requirements, so as to improve the product grade and meet the smelting requirements.

III. Technological Advantages and Value: From Environmental Burden to Profit Creation

Investing in advanced brown iron tungsten-containing ferro tin recycling and separation technology brings multiple values to the enterprise:

• Comprehensive utilization of resources: the traditionally abandoned or stockpiled tailings and slag materials are transformed into tungsten concentrate, tin concentrate and iron concentrate with high market value, realizing the "exhaustion" of resources.

• Remarkable economic benefits: opening up a new source of income, especially in the context of the increasingly tense global tungsten and tin resources, the economic returns are very substantial.

• Environmental protection and safety: Reduce the environmental risks and land occupation brought by solid waste stockpiling, which is in line with the development direction of green mine and circular economy.

• High technical barriers: Mature joint process design and optimization capability constitutes the core competitive advantage, capable of stable output of qualified products.

IV. Conclusion: Choose a professional partner to unlock the potential of complex resources

Recovery of tungsten-tin ore of brown iron type is a technology-intensive systematic project, and its success relies on a deep understanding of mineral properties and precise coupling of multiple processes.

We specialize in the comprehensive utilization of complex and difficult-to-process resources, and provide a full set of technical solutions for the recovery and separation of tungsten and tin ores containing brown iron, from material testing, process development, selection of core equipment to turnkey operation. We are committed to helping you turn every seemingly worthless complex resource into a real competitive advantage through technological innovation.

Contact us today for exclusive technical consulting and feasibility analysis reports, and together we will create a new chapter in the value of renewable resources!