Table 3 Proposed practices for salt-iodation at different scales of salt production
From: Improved salt iodation methods for small-scale salt producers in low-resource settings in Tanzania
Practice | Large scale salt producer | Medium scale salt producer | Small scale salt producer |
|---|---|---|---|
Quantity to iodate | Above 100 tons/day | 1 – 100 tons/day | Below 1000 kgs/day |
Type of iodating equipment/utensils | Conventional salt iodating machines | Knapsack sprayers with slit nozzles | Knapsacks if externally provided, otherwise 1 – 2 litre hand bottle sprayers |
Iodation procedure | Machine calibrated spraying with automated mixing of salt | Hand pump spraying with manual shovel mixing or cement mixer | Hand pump spraying with manual mixing on mat |
Amount of KIO3 used | 76.5 g/ton | 20 litres of solution (10 g/l) to iodate an average heap (2.5 tons) | Solution of 20 g in 2 litres to iodate an average of five 50 kg bags |
Frequency of spraying to achieve recommended levels | Machine calibrated and controlled | 2 – 4 times with manual mixing and 2 – 3 times with concrete mixer | 4 – 5 times with hand bottle sprayers and manual mixing on mat |
Homogeneity | Excellent | Good | Fairly good |
Quality control | Laboratory control (both RTK and titration methods) | Laboratory control (both RTK and titration methods) | Semi quantitative method (RTK) |
Frequency of internal quality control to determine magnitude of iodine variability* | Periodic validation of iodation processing and batch to batch iodine testing | Daily/periodic validation of iodation processing and batch to batch iodine testing | Daily validation of iodation processing and batch to batch iodine testing |