1.Background, technology
The ternary precursor materials need to be washed with pure water in the synthesis process, and 20-25 tons of pure water are required for each ton of ternary precursor products. The wastewater obtained by aging and dehydration contains heavy metals, ammonia nitrogen and other pollution indicators, which belongs to typical ammonia nitrogen wastewater. The heavy metals and ammonia nitrogen must be removed before discharge.
The national environmental protection requirements have strict standard requirements for industrial wastewater discharge. Sewage treatment equipment must be equipped to meet the national discharge standards. Industrial wastewater enters the evaporative crystallization treatment process system after pretreatment links such as filtration, neutralization and removal of heavy metals, so as to realize zero discharge of industrial wastewater and meet the requirements of environmental protection discharge standards.
2. StarOne process
Aiming at the disadvantages of large water consumption, poor effect, large unit consumption and high operation cost of ternary precursor washing wastewater recovery and treatment, StarOne has developed a method with simple operation, adjustable treatment capacity and low investment, which can effectively separate and recover valuable elements such as ammonia nitrogen, heavy metals, salt and water in ternary precursor washing wastewater.
The process design follows the principles of wastewater resource treatment and zero discharge, and can realize the preparation of pure water while meeting the concentration of washing water. The concentration of washing water adopts membrane process. After mixing the produced water of the concentration system and the condensate of the ammonia containing wastewater evaporator, the final produced water can meet the industrial desalted water standard after being treated by multi-stage reverse osmosis process.
When the desalting water prepared from the condensate of washing water and ammonia containing wastewater evaporator cannot meet the use requirements, the tap water inlet valve of the system can be opened to supplement the water and ensure that the final produced water quality is stable and meets the industrial desalting water standard.
3. Process advantages of StarOne
1. The concentration of recovered ammonia is 15% - 20%, the recovery rate of ammonia nitrogen is more than 99%, and the ammonia nitrogen of concentrated brine is less than 15mg / L.
2. Conductivity of recyclable pure water ≤ 10 μ S/cm。
3. All heavy metals are recovered.
4. Reduce the evaporation of washing water by 80% - 90% and reduce the operation cost by more than 50%.
5. The process is relatively simple, with high reliability, stable operation and low maintenance cost.
4. Industry cases
Take the three yuan wastewater zero discharge project of an enterprise as an example:
The designed processing capacity of the system is 80m3 / h.
Water quality parameters of ternary washing wastewater:
Serial number | project | Company | numerical value |
1 | Na | （g/L） | 3-3.7 |
2 | SO42- | （g/L） | 6.5-7.8 |
3 | Cl- | （mg/L） | ≤0.7 |
4 | NH4-N | （mg/L） | ≤200 |
5 | COD | （mg/L） | ≤5.2 |
6 | Ni | （mg/L） | ≤0.3 |
7 | Co | （mg/L） | ≤0.1 |
8 | Mn | （mg/L） | ≤0.1 |
9 | Ca | （mg/L） | ≤3.2 |
10 | Mg | （mg/L） | ≤0.1 |
11 | Fe | （mg/L） | 0 |
12 | Zn | （mg/L） | ≤0.1 |
13 | Cr | （mg/L） | ≤0.1 |
14 | pH | / | ≥11 |
Effluent quality
（1） Water quality parameters of recycled pure water:
Serial number | Inspection items | Company | requirement | Testing instrument Or method |
1 | appearance | / | Colorless Transparent Liquid No sundries | Visual inspection |
2 | conductivity | μS/cm(25℃) | ≤10 | Titration |
（2） Ammonia recovery index:
Serial number | Inspection items | Company | requirement | Testing instrument Or method |
1 | Appearance | / | Colorless Transparent Liquid No sundries | Visual inspection |
2 | NH3 | % | ≥16 | Titration |
3 | Na | （g/L） | ≤0.02 | ICP/AAS |
4 | Fe | （g/L） | ≤0.003 | ICP/AAS |
5 | Cu | （g/L） | ≤0.001 | ICP/AAS |
6 | Ca | （g/L） | ≤0.01 | ICP/AAS |
7 | Mg | （g/L） | ≤0.01 | ICP/AAS |
8 | Zn | （g/L） | ≤0.002 | ICP/AAS |
