|
Specification |
90% |
88% |
85% |
Food grade |
|
Na2S2O4 |
≥90% |
≥88% |
≥85% |
≥85% |
|
Fe |
≤20ppm |
≤20ppm |
≤20ppm |
≤20ppm |
|
Zn |
≤1ppm |
≤1 ppm |
≤1ppm |
≤ 1ppm |
|
Solution Appearance |
Clear |
Clear |
Clear |
Clear |
|
Other heavy metal (as pb) |
— |
— |
— |
— |
|
HCHO |
— |
— |
— |
≤0. 05% |
|
Water insoluble matter |
≤0.05% |
≤0.05% |
≤0.05% |
— |
|
Reserve period (months) |
12 |
12 |
12 |
12 |
