| Vendor | Spec | Unit | Price | Currency | Date |
| Henan Qingmai Environmental Protection Technology Co., Ltd. | China national standards | MT | 407.84 | USD | 20250922 |
| Henan Qingmai Environmental Protection Technology Co., Ltd. | China national standards | MT | 407.72 | USD | 20250919 |
| Henan Qingmai Environmental Protection Technology Co., Ltd. | China national standards | MT | 407.96 | USD | 20250918 |