What About Safety and Storage?

Direct Answer

Direct Answer First, a clarification: thiourea dioxide is not a harmless substance. Its better safety profile is relative to hydrosulfite, and protective measures are still required.

Hazard classification (per the product SDS)

Product data (from the technical data sheet)

Personal protection

• Wear a dust mask, goggles, chemical-resistant gloves and long-sleeved workwear
• Avoid dust generation when charging; work in a ventilated area or fit local extraction
• Avoid contact with eyes and broken skin; in case of contact rinse immediately with plenty of water and seek medical attention

Storage conditions

Preparing solutions

• Solubility in water at 20 C is 26.7 g/L
• In the strongly caustic alkaline range up to 100 g/L dissolves at 20 C, but these alkaline solutions are comparatively unstable
• Stock solutions should be prepared with cold water
• Caustic soda should be added only shortly before use
• Alkali-free solutions are almost stable for up to 6 hours at room temperature

How it differs from hydrosulfite

Thiourea dioxide does not self-ignite or support combustion, so storage and transport are far less demanding. Hydrosulfite is a water-reactive substance releasing flammable gas, and requires temperature and humidity control, no loading in rain and airtight packaging.

Bottom line

Follow the SDS for protection and store tightly closed, cool and dry below 25 C. Prepare stock solutions with cold water, add the alkali only shortly before use, and keep the product away from oxidants, metal salts and alkalis.

Sources

1. 我司产品技术数据表《THIOUREA DIOXIDE Technical Data Sheet》（TDO-TDS，签发日期 2024-05-08）
2. 我司产品 SDS 与 TDS（危害分类、运输分类、热分解温度、溶解度等物性数据）