Filtration, Washing, and Drying in Hydrometallurgical Battery Recycling Integrated Post-Treatment from Black Powder to Battery-Grade Lithium Salts
As the 50,000-ton spent lithium battery comprehensive utilization project lands in Hebei, and as the Battery Recycling Committee predicts that China's retired batteries will exceed 2.8 million tons by 2030, with a market value of RMB 300 billion — the battery recycling industry is shifting from "environmental disposal" to "resource competition."
As recycling capacity expands, competition is increasingly focused on whether recovered materials can consistently meet battery-grade specifications.
In hydrometallurgical refining, filtration, washing, and drying directly affect product purity, moisture content, and batch consistency.
I. The Role of Hydrometallurgy in Battery Recycling
The mainstream route for spent lithium battery recovery consists of two stages: physical shredding and sorting, and hydrometallurgical refining.
Physical Stage: Batteries are disassembled, shredded, and sorted to obtain "black powder" containing valuable metals such as lithium, cobalt, and nickel. This stage is "separation."
Hydrometallurgical Stage: Acid or alkali is used to leach valuable metals from the black powder, followed by chemical processes to separate, purify, and crystallize lithium, cobalt, nickel, and other elements from the complex solution in the form of high-purity lithium carbonate, cobalt sulfate, etc.
This stage determines whether recovered metals can return to downstream applications as qualified products.
Industry research clearly indicates that as an intermediate product connecting spent batteries and recycled metals, the purity, particle size, moisture content, and impurity levels of black powder directly affect the subsequent recovery efficiency of nickel, cobalt, manganese, and lithium. The value of black powder preparation equipment is expanding from "single-machine shredding capacity" to "full-process material control capability."
The 3-in-1 Filter-Dryer is used in the filtration, washing, and drying stages of this material-control process.
II. Where the 3-in-1 Filter-Dryer Fits in Hydrometallurgy
In the hydrometallurgical refining process, after leaching, impurity removal, and precipitation, the slurry must undergo solid-liquid separation, washing, and drying to produce products that meet battery-grade purity requirements.
The traditional process route is: Precipitation reaction → Centrifuge (solid-liquid separation) → Washing tank (washing) → Dryer (drying)
This multi-equipment arrangement commonly presents three issues:
Materials are repeatedly transferred between equipment, increasing contamination risk with each transfer
Rinsing cannot penetrate deep into the filter cake, resulting in high impurity residue
Multiple equipment in series results in large footprint, extensive manual intervention, and poor batch consistency
The 3-in-1 Filter-Dryer integrates filtration, washing, and drying into a single fully enclosed vessel, completing solid-liquid separation, multi-stage counter-current washing, and vacuum drying in one equipment.
Because the material does not need to move between machines, exposure and product loss can be reduced and batch consistency can be improved.
III. Five Process Functions of the 3-in-1 Filter-Dryer
1. Deep Washing to Reduce Soluble Impurity Residues
Battery-grade lithium carbonate has extremely stringent requirements for impurities such as sodium, potassium, calcium, and magnesium. The 3-in-1 Filter-Dryer features a fully automatic spray system combined with the S-type agitator's lifting and bi-directional rotation, enabling multi-stage counter-current washing. The washing liquid uniformly penetrates deep into the filter cake, effectively displacing soluble impurities in the residual mother liquor and controlling impurity content within battery-grade standards.
In contrast, the rinsing method of traditional centrifuges can only wash the filter cake surface, cannot penetrate deep inside, resulting in limited washing effectiveness and high detergent consumption.
2. Fully Enclosed Operation to Reduce Material Exposure
During spent battery recycling, materials such as electrolytes, acids, and organic solvents are toxic, corrosive, or flammable and explosive. The 3-in-1 Filter-Dryer operates in fully enclosed mode from feeding to discharge, eliminating harmful gas volatilization and dust leakage, meeting increasingly stringent environmental and safety compliance requirements.
Industry research indicates that compliance requirements are becoming a key driver in the battery recycling industry. EU battery regulations set clear requirements for waste battery recycling efficiency and critical metal recovery rates, pushing recyclers from crude dismantling and simple sorting toward high-recovery, traceable, and scalable processing.
3. Process Integration to Reduce Equipment and Transfers
The 3-in-1 Filter-Dryer integrates processes that traditionally required three or more pieces of equipment into one unit, with value reflected in:
Metric | Traditional Multi-Equipment Process | 3-in-1 Filter-Dryer
Floor Space | Baseline | Reduced by more than 50%
Material Exposure | 3-4 times | Zero
Product Loss Rate | 2-5% | Below 1%
Manual Intervention | Frequent | Minimal
Batch Consistency | High variation | Highly consistent
4. Automation and Traceability — Meeting Supply Chain Audit Requirements
A PLC+HMI system controls the equipment and records parameters such as washing cycles, temperature profiles, vacuum levels, and agitation speeds. These records support downstream customer audits and batch traceability.
5. Skid-Mounted Integration — An Industry Trend for Rapid Deployment
Battery recycling projects typically adopt skid-mounted or modular delivery to reduce on-site construction time and costs. The 3-in-1 Filter-Dryer can be integrated as a core unit into the skid system, achieving "factory prefabrication and rapid on-site assembly." This delivery model has been validated in the industry, with the 3-in-1 Filter-Dryer widely applied in lithium carbonate, ternary precursor, cathode material, and spent battery recycling fields.
IV. Demand for Refining Equipment in Battery Recycling
In October 2026, the "2026 China Power Battery Recycling Industry Annual Conference" will be held in Ganzhou, Jiangxi, with the theme "Green Cycle Lithium Source · Low-Carbon Regeneration." The 50,000-ton spent lithium battery comprehensive utilization project in Hebei has landed, and the global battery black powder recycling equipment market is shifting from "environmental disposal equipment" to "critical infrastructure in the battery material supply chain."
These projects and industry activities indicate greater investment in refining, purification, and quality control.
In hydrometallurgical refining, the 3-in-1 Filter-Dryer combines enclosed operation, deep washing, vacuum drying, and parameter recording to help control purity, moisture content, and batch consistency.
Wuxi Zhanghua Pharm & Chem Equipment Co., Ltd.
Founded in 1976 · Nearly 50 years as a core manufacturer of reaction, crystallization, filtration, and drying equipment
3-in-1 Filter-Dryer (ANFD) — Applicable for spent lithium battery hydrometallurgical recovery, lithium salt purification, ternary precursor post-treatment, and other battery material recycling fields
Contact us for technical proposals and case references.
Contact: Manager Zhang
Tel: 13961802200 (same number on WeChat)
Email: zqz008@126.com
Website: www.jszhanghua.com