Ozone Cyclonic Air Flotation (CDOF) for Ternary Precursor Wastewater: A Breakthrough in Oil Removal
In the production of nickel-cobalt intermediates, the preparation of ternary precursors is always accompanied by the generation of raffinate and stripping liquors. These streams consist mainly of P204, P507 and their diluent, sulfonated kerosene. After saponification and acidification, part of the organic phase dissolves into the aqueous phase, which affects subsequent equipment operation and water reuse — making effective oil removal a critical step.
Such raffinate and stripping liquors carry a high oil content, exhibit a low pH due to sulfuric-acid stripping, and are rich in SO₄²⁻, Na⁺ and NH₄⁺ ions. These characteristics make biological treatment unsuitable, while the need to reuse the water restricts chemical dosing, rendering conventional chemical treatment equally impractical. Physical methods require no chemicals but have limited treatment capacity, so choosing a treatment route for this kind of wastewater is genuinely difficult.
The ozone cyclonic air flotation process introduced by SINOKLE Technology integrates three advanced technologies: ozone catalytic oxidation, hydrocyclone separation and air flotation oil removal. This integrated unit (CDOF) can efficiently reduce the oil content of raffinate and stripping liquors to below 5 mg/L without interrupting normal production line operation.
Technical Highlights of the SINOKLE CDOF Unit
Multiple technologies working in concert — a domestically pioneering, internationally leading technology.
Efficiency: ozone oxidation efficiency is 2–4 times that of conventional processes, reducing ozone dosage and cost.
No chemical additives, no secondary pollution, no impact on subsequent processes.
Fast treatment rate, short residence time and a compact footprint.
Closed, pressurized operation with no ozone leakage — safe, environmentally friendly and without impact on on-site work.
Fully automated and intelligent, supporting remote operation guidance — no on-site staffing required.
Comparison with Conventional Processes
| No. | Item | Flotation + Settling Oil Removal | CDOF (Integrated Ozone Flotation Unit) |
|---|---|---|---|
| 1 | Effluent quality | Oily (suspended-solids-bearing) wastewater | Oily (suspended-solids-bearing) wastewater |
| 2 | Residence time | 60 min | <15 min |
| 3 | Oil removal efficiency (single stage) | 60%–85% | >90% |
| 4 | Suspended solids removal (single stage) | 50%–70% | >80% |
| 5 | Operation mode | Manual, open-type | Automatic, closed operation |
| 6 | Oil discharge | Relies on skimmer, mechanical slag discharge | Pressurized oil and slag discharge, no mechanical power |
| 7 | Technical features | Long residence time, large footprint, low flotation efficiency, chemical dosing required, unstable oil removal | Compact structure, small footprint (1/3 of conventional), high removal of emulsified oil and fine suspended solids, no chemicals needed |
| 8 | Application scope | Onshore sites where footprint and weight are not critical | Especially suitable for difficult wastewater such as raffinate/stripping liquor containing emulsified oil |
| 9 | Structure | Reinforced concrete | Pressurized-vessel skid-mounted equipment |
| 10 | Operating cost | High ozone consumption, high capital cost | Low ozone consumption, low construction and operating cost |
| 11 | Site environment | Risk of ozone leakage | Fully enclosed operation, safe and environmentally friendly |
