In high-tech industries such as LCD panels, semiconductor materials, and photovoltaic cells, indium is an indispensable “vitamin.” However, primary indium resources are scarce and expensive. With the surge in electronic waste—such as discarded LCD screens and ITO target scraps—the value of recovering indium from “urban mines” is increasingly apparent.

In hydrometallurgical indium recovery, the extraction step is critical in determining both metal purity and recovery rate. How can indium be efficiently and precisely extracted from complex waste solutions while minimizing operational costs? Zhengzhou Tiei Extraction’s independently developed CWL-M series centrifugal extractor provides an efficient and intelligent solution for hydrometallurgical indium recovery.

Indium Recovery from Waste Materials: Core Hydrometallurgical Process

From waste materials to high-purity indium metal, the core hydrometallurgical steps are as follows:

1.Pre-treatment and Leaching
Waste materials are crushed and ground, then leached using sulfuric acid or hydrochloric acid. During this process, indium ions (In³⁺) enter the leachate, along with a large amount of impurity metals such as tin, iron, aluminum, and copper.

2.Extraction and Enrichment (Key Step)
The leachate contains a high concentration of impurities that must be separated through extraction, typically using extractants such as P204 or Cyanex 272.

Extraction: The indium-containing leachate is mixed with an organic extractant in extraction equipment. Through chemical affinity, indium ions are selectively captured into the organic phase, while most impurities remain in the aqueous phase and are discarded.

Washing: The loaded organic phase is washed to remove minor entrained impurities, further improving purity.

Stripping: The organic phase is treated with a high-concentration acid to strip indium from the organic phase, yielding an indium-rich strip solution. The organic phase is regenerated for recycling.

3.Purification and Production
The resulting strip solution undergoes displacement, electrolysis, or further deep purification to produce high-purity indium sponge or refined indium.

Pain Points of Traditional Extraction Equipment

In conventional indium recovery processes, mixer settlers or extraction columns are commonly used. However, when handling complex waste solutions, they often face the following challenges:

Severe Emulsification: The complex composition of the waste solution often leads to emulsification, making phase separation difficult.
High Solvent Losses: Significant entrainment not only wastes expensive extractants but also negatively impacts product quality.
Large Footprint: Achieving effective separation typically requires multi-stage cascades, occupying a large amount of floor space.
Low Stage Efficiency: Insufficient mass transfer leads to an increased number of theoretical stages, making the process lengthy and inefficient.

CWL-M Centrifugal Extractor: The “Performance Engine” for Indium Recovery

To address the specific challenges of hydrometallurgical indium recovery, Zhengzhou Tiei Extraction developed the CWL-M series centrifugal extractor, offering a completely new solution. By generating strong centrifugal force through high-speed rotation, gravity-driven phase separation is replaced, perfectly meeting the requirements for clean, efficient, and low-loss indium extraction.

1.Process Optimization

a.Efficient Mass Transfer: In the mixing zone of the centrifuge, the indium-containing aqueous solution and the organic phase are intensively mixed in a very short time, ensuring rapid phase transfer of indium ions.

b.Instantaneous Phase Separation: The mixed solution enters the drum, where centrifugal force instantly separates the light and heavy phases. Even systems with small density differences or high emulsification tendencies achieve clear phase separation.

c.Cascaded Countercurrent Operation: Users can connect multiple CWL-M centrifugal extractors in series according to process requirements, achieving countercurrent extraction or stripping. This easily accomplishes 3–5 stages or even higher of efficient separation, ensuring high indium recovery rates.

2.Key Advantages

a.Ultra-Low Solvent Entrainment, Saving Expensive Extractants
In indium extraction, extractants (e.g., P204) and solvents (sulfonated kerosene) are costly. Thanks to complete phase separation, the CWL-M centrifugal extractor has minimal organic phase entrainment, reducing solvent consumption by over 30% compared to traditional equipment and significantly lowering operating costs.

b.Exceptional Anti-Emulsification Capability for Complex Solutions
For leachates with high surfactant content that are prone to emulsification, the strong centrifugal force disrupts emulsified layers, preventing “third phase” formation and ensuring stable long-term operation.

c.Automated Continuous Operation, Reducing Labor Costs
The centrifuge can start and stop within minutes, unlike mixer settlers that require long feed-and-discharge equilibration. During operation, the system can be fully PLC-controlled, ideal for modern smart factories and continuous production.

d.Minimal Footprint, Maximized Plant Utilization
A single centrifuge can handle the throughput of a large mixer settler but occupies only 1/5 to 1/10 of the space, making it perfect for retrofits or projects with limited floor space.

CWL-M Centrifugal Extractor: Application Cases and Value Demonstration

In a retrofit project at an electronic waste recycling company recovering ITO waste targets, indium extraction was originally performed using mixer settlers, which often led to production stoppages due to severe emulsification. After switching to a three-stage countercurrent CWL-M centrifugal extractor system from Tiei Extraction:

Improved Recovery Rate: The overall indium recovery rate increased from 92% to over 98%.
Reduced Solvent Consumption: Organic phase consumption costs decreased by 40%.
Higher Product Purity: The indium concentration in the strip solution increased, reducing the burden for subsequent electrolytic refining.

As indium becomes an increasingly valuable resource, efficient recovery is not only an environmental necessity but also a significant economic benefit. Zhengzhou Tiei Extraction, as a professional manufacturer of liquid–liquid extraction equipment, is committed to providing superior support for the precious and rare metal recovery industry with the CWL-M centrifugal extractor.
If you are seeking solutions to challenges such as emulsification, entrainment, or low efficiency in indium recovery, please contact us for process testing and equipment selection advice.
Email: sales@tieiextraction.com
Whatsapp: +86 19069612820