Continuous chemical equipment
provider
provider
The global nickel-cobalt industry faces pressing challenges: high-grade ore reserves are depleting, while low-grade resources (Ni <1%, Co <0.1%) suffer from low efficiency, poor separation, and insufficient recovery in traditional processes. Meanwhile, booming new energy demand has intensified pressure on supply chains, and stricter environmental regulations require greener, cost-effective technologies. In this context, mixer-settlers (extraction tanks) have emerged as core equipment to bridge leaching and purification, addressing bottlenecks in low-grade nickel-cobalt processing. With simple structure, stable operation, strong adaptability, and low maintenance costs, they enable efficient enrichment and precise separation of nickel and cobalt via optimized "mixing-mass transfer-phase separation" workflows, supporting primary ore treatment, waste battery recycling, and wastewater management. This article explores their specific applications, technical advantages, and practical cases in low-grade nickel-cobalt resource utilization.
Low-grade primary ores, including laterite nickel ore and low-grade sulfide nickel ore, are characterized by low nickel-cobalt content and high impurities (magnesium, iron, calcium, etc.). Traditional pyrometallurgy features high energy consumption and heavy pollution, while hydrometallurgy has become the mainstream route—with mixer-settlers undertaking critical separation and enrichment tasks.
Laterite nickel ore, the most abundant low-grade nickel resource, contains nickel mainly in magnesium silicate minerals and cobalt in oxide zones, with over 98% acid-consuming gangue clays. Mixer-settlers adapt to high-magnesium, low-nickel-cobalt leachates via multi-stage countercurrent extraction. Using organic acid extractants (e.g., Versatic 10), they achieve selective nickel-cobalt extraction and impurity removal.
Practical Case: In a Jinchuan nickel-cobalt processing plant, optimized mixer-settlers addressed high viscosity and small density differences in laterite leachates. By adjusting stirring power density to 0.8–1.5 kW/m³ and extending settling time, cobalt recovery rose from 78% to over 92%, wastewater cobalt content dropped from 0.15 g/L to 0.008 g/L, and extractant consumption decreased by 40%—saving over 5 million RMB annually in environmental and material costs.
Low-grade sulfide ores often coexist with copper, iron, and zinc, requiring efficient separation of nickel, cobalt, and impurities. Mixer-settlers adopt staged extraction-scrubbing-stripping workflows:
Extraction Stage: Selective extraction of nickel and cobalt using di-2-ethylhexyl phosphoric acid (P204) or 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507) to separate from iron and copper.
Scrubbing Stage: Remove entrained impurities with dilute acid to improve organic phase purity.
Stripping Stage: Strip nickel and cobalt into aqueous solution using concentrated acid for subsequent refining.
This process achieves 95%+ nickel recovery and 90%+ cobalt recovery, with final product purity meeting battery-grade standards (99.9%).
The surge in new energy vehicles has led to massive retired NMC batteries, rich in nickel, cobalt, and manganese—making them critical "urban mines". Mixer-settlers play a vital role in leachate purification and metal separation, addressing low concentration and complex impurities in battery leachates.
Spent NMC battery leachates contain high manganese and iron, requiring selective nickel-cobalt recovery. Mixer-settlers use Versatic 10 (diluted in Isopar L) as extractant for two-stage countercurrent extraction. With an organic-to-aqueous phase ratio of 1:1 and 0.9 M Versatic 10, near-100% nickel recovery and 99.26% nickel sulfate purity are achieved after crystallization.
Cobalt and manganese separation is challenging due to similar chemical properties. Mixer-settlers adopt P507 extractant with optimized pH and phase ratio: cobalt is extracted into the organic phase, while manganese remains in the aqueous phase. Multi-stage (8–10 stages) countercurrent operation achieves 98%+ cobalt-manganese separation efficiency, producing cobalt sulfate solution suitable for battery material production.
Nickel-cobalt wastewater from electroplating, smelting, and battery manufacturing features low metal concentration, high impurity content, and strict discharge standards. Mixer-settlers enable efficient metal recovery and wastewater compliance, supporting circular economy goals.
For electroplating wastewater with nickel concentration >1 g/L, P204-kerosene systems in mixer-settlers achieve 99%+ nickel extraction efficiency. After stripping, nickel sulfate solution is reused in electroplating, reducing raw material costs and environmental pollution.
Smelting wastewater with nickel <0.5 g/L and high iron/aluminum impurities requires multi-stage extraction and impurity removal. Mixer-settlers adjust phase ratio (2:1 to 3:1) and stirring speed (200–500 rpm) to stabilize nickel extraction at >93% despite 20% concentration fluctuations. Treated wastewater meets GB 8978-1996 discharge standards, with nickel concentration <0.1 mg/L.
Mixer-settlers handle high-impurity, fluctuating-concentration leachates better than centrifugal extractors. Their independent mixing-settling zones accommodate varying viscosity and density differences, avoiding emulsion issues and ensuring continuous production.
Single-stage separation efficiency exceeds 85%, with 10-stage series achieving 97%+ comprehensive recovery. Optimized hydraulic design minimizes back-mixing, enhancing nickel-cobalt selectivity and product purity.
Low Energy Consumption: Gravity settling reduces energy use by 30% vs. centrifugal extractors.
Low Maintenance: Simple structure and corrosion-resistant materials (PP, PVC, lined steel) extend service life and reduce upkeep.
Reduced Extractant Loss: Effective phase separation lowers entrainment losses by 40%, cutting material costs.
Modular design enables seamless scale-up from laboratory (CC-type) to industrial scale (800 m³/day). Visual sampling ports allow real-time interface monitoring, simplifying operation and reducing labor costs.
Mixer-settlers have become indispensable in low-grade nickel-cobalt resource utilization, with proven applications in primary ore processing, spent battery recycling, and industrial wastewater treatment. By enabling efficient enrichment, precise separation, and cost-effective production, they address core industry pain points—low efficiency, high costs, and environmental pressure—while supporting sustainable development and new energy supply chain security. As extractant and control technologies advance, mixer-settlers will play an even greater role in unlocking the potential of low-grade nickel-cobalt resources.
Focus on being Continuous chemical equipment
provider.
If you want to learn more about our centrifugal extractor, mixer settler, Contact us Now