120t/d Lithium Carbonate MVR Evaporation Crystallization System

I.Project Background

With the explosive growth of the global new energy vehicle industry and energy storage market, the demand for lithium carbonate, a core cathode material for lithium batteries, continues to rise, and production capacity is rapidly expanding. During lithium extraction from lepidolite and spodumene, or the recycling of spent batteries, large amounts of lithium-containing evaporation mother liquor or brine lake lithium enrichment solutions are generated. Traditional batch evaporation crystallization methods are energy-intensive and produce unstable product purity, becoming a bottleneck restricting capacity expansion and cost control. To enhance its core competitiveness, a leading lithium battery material manufacturer commissioned our company to build a large-scale, continuous, and stable lithium carbonate crystallization and purification system.

II.Solution

Facing this challenge, our company successfully designed, built, and put into operation this lithium carbonate MVR evaporation crystallization system with a processing capacity of 120 tons/day. This system, based on mechanical vapor recompression (MVR) technology, deeply integrates the physicochemical properties of lithium carbonate, achieving a high degree of efficiency, cost-effectiveness, and product quality in large-scale production, providing strong technical support for the client's sustainable development.

III.Core System Advantages

1.Scale and Energy Efficiency, Enabling Cost Reduction and Efficiency Improvement

Facing a daily processing capacity of 120 tons, traditional evaporation methods would incur astronomical steam costs. This system employs a high-efficiency centrifugal steam compressor, recovering and reusing almost all secondary steam, resulting in a high system coefficient of performance (COP). With the support of economies of scale, energy consumption per unit product is reduced to a low level, giving customers a significant cost advantage in the production of bulk chemical raw materials.

2.Precise Crystallization Control, Ensuring Battery-Grade Product Purity

Battery-grade lithium carbonate has extremely stringent requirements for purity, particle size, and crystal morphology. This system, through a DCS control system, precisely controls key parameters such as evaporation temperature, pH value, feed rate, and supersaturation, creating the optimal crystallization environment. The final product is battery-grade lithium carbonate with regular morphology, concentrated particle size, and a stable purity of over 99.5%, which can be directly used in downstream cathode material production.

3.Superior Anti-scaling and Corrosion-resistant Design: Lithium liquid is prone to scaling on heat exchange surfaces during evaporation, affecting heat transfer efficiency and continuous operating time. The system employs a combined "Forced Circulation (FC) + Oslo (OSLO)" crystallization process. High-flow-rate circulation prevents crystallization within the heating tubes, while providing a favorable growth environment for crystals within the crystallizer, effectively mitigating scaling. The main body of the equipment in contact with materials is made of 316L or higher grade stainless steel, ensuring long-term corrosion resistance and service life under complex operating conditions.

4.High Level of Intelligence and Stability: The entire system features one-button start/stop and fully automatic operation. The central control room can monitor the operating status of all equipment in real time. The system has automatic correction, safety interlock, and early warning functions, ensuring continuous and stable operation for up to 7200 hours/year under a high load of 120t/d, significantly guaranteeing the overall operational efficiency of the customer's production line.

5. Green Recycling, Closed-Loop Production:

The system produces high-quality distilled water that can be reused as pure process water in upstream processes such as leaching and washing, significantly reducing fresh water consumption during production. This not only achieves closed-loop utilization of water resources but also reduces wastewater discharge at the source, perfectly meeting the green and environmentally friendly requirements of the lithium battery industry chain.

IV. System Process Flow Overview

1.Refining and Preheating: Qualified lithium source solution from the upstream process first enters a multi-stage integrated preheater, where it undergoes multi-stage heat exchange with the system's condensate and mother liquor, maximizing heat recovery.

2.MVR Forced Circulation Evaporation: After preheating, the solution enters a forced circulation evaporator, where it is indirectly heated by compressed high-temperature steam as it flows at high speed through the heating tubes. After entering the separation chamber, it undergoes flash evaporation concentration.

3.OSLO Crystallization and Growth: The concentrated supersaturated solution enters the OSLO crystallizer, where a balance between crystal growth and supersaturation desaturation is achieved, cultivating large and uniform lithium carbonate crystals.

4.Thickening and Separation: The crystal slurry is discharged from the bottom of the crystallizer and enters the thickener for concentration. It is then sent to a centrifuge for solid-liquid separation to obtain wet lithium carbonate.

5.Drying and Packaging: The wet material is dried in a disc dryer or belt dryer using a low-temperature, high-volume airflow method to finally obtain powdered battery-grade lithium carbonate, which is then packaged and stored.

6.Steam Circulation: The secondary steam generated throughout the evaporation process is pressurized by a compressor and used as the main heat source for recycling. The condensed pure water is reused in production.

V.Project Achievements and Customer Value

The successful commissioning of this 120t/d lithium carbonate MVR evaporation and crystallization system marks a significant breakthrough in my country's equipment for preparing core lithium battery materials, creating substantial value for customers:

1.Economic Benefits: Annual savings of over 10,000 tons of standard coal consumption; operating costs reduced by over 50% compared to traditional methods; high-quality pure water as a byproduct; and a return on investment period far below the industry average.

2.Quality and Production Capacity: The product purity consistently meets battery-grade standards, helping customers seize the high-end market; large-scale continuous production ensures a stable supply of raw materials, strongly supporting the rapid release of customer production capacity.