Filter Media – MANGANESE DIOXIDE
Technical data
Material – Manganese dioxide
Uses – Catalytic iron and manganese removal from potable water.
Physical properties
| Specific gravity | 3.5 4.0 |
| Bulk density | 1800 2000kg.m3 |
| Hardness | 2 3 Moh |
Chemical properties
Natural manganese ores specially selected for their high catalytic activity, free from contamination and with no additives, are used in the production of this manganese dioxide. The manganese content varies between 55 and 85% as MnO2, but the catalytic activity is not dependent upon the manganese content.
Particle size
18/44 B.S. mesh, 0,355 0.850mm. A maximum of 5% of the product is coarser than 0.850mm, and a maximum of 5% is finer than 0.355mm. Additionally, no more than 10% of the product is finer than 0,425mm.
Method of use
The usual procedure for used in rapid gravity and pressure filters is to add up to 20% by volume of manganese dioxide to a bed of B.S 16/30 (0.50 1.00mm) or B.S 14/25 (0.600 1.18mm) sand. After backwashing, the manganese dioxide will remain evenly distributed throughout the bed, thus ensuring maximum contact time between the water and the catalytic medium. The prepared sand and manganese dioxide bed should be backwashed gently before service. It is not necessary to backwash the sand before placing the manganese dioxide. Five bed volumes are usually sufficient to complete the washing after which the bed may be put into service, discarding the first half bed volume of filtered
water.
Performance
A bed constructed as above will behave in an identical manner to a bed of 100% B.S, 16/30 or B.S, 14/25 sand in respect of its filtration and backwash characteristics. Typical filtration rates in rapid gravity filters are of the order of 10m.h-1 but higher velocities are often used in pressure filters. In determining the optimum filtration velocity, a minimum contact time of 6 minutes should be used. Combined backwash and air scour is not recommended and backwash velocities should not exceed 25m.h-1.
Packaging
25-kg multi-wall paper sacks palletised and shrink-wrapped.
Safety data sheet
Product Manganese dioxide
Description
Dark brown granular solid
Manufacturer’s intended use
For the removal of iron and manganese from potable water by incorporation in a bed of sand or alone in rapid gravity and pressure filters.
Composition
A naturally occurring manganese ore whose main constituent is manganese dioxide in the form of pyrolusite.
Fire hazard
No fire or explosion hazard. However, manganese dioxide is an oxidising agent and should not be stored with reducing agents.
Decomposition products
Chlorine gas is evolved on contact with hydrochloric acid.
Oxygen is evolved on heating above 500ºC.
Health hazards
Manganese poisoning is a notifiable industrial disease. Its occurrence is rare, and comes about only after prolonged exposure to manganese dioxide dust and/or ingestion of substantial quantities.
Prolonged contact with the skin may, in certain individuals, produce sensitisation leading to contact dermatitis.
Precautions
Exposure to manganese dioxide dust should be kept as low as reasonably possible. This may be achieved by the application of appropriate industrial hygiene methods, and the use of appropriate personal protective equipment. Such equipment would include respiratory protective equipment of a type approved by the Health and Safety Executive and eye protection. Barrier creams should also be used on exposed skin.
Spillage
In the event of spillage, avoid breathing dust. Wear appropriate
respiratory and eye protection and sweep up.
Disposal
Any spilwt or surplus manganese dioxide may be disposed of by an solid-waste disposal method.
First aid
Eyes: Flush with copious quantities of water Skin: Wash with soap and water Ingestion: Non-toxic Inhalation: Remove patient to fresh air and seek medical advice.
Hazard data
TLV 5mg.m3
Flash point, boiling point, and vapour pressure not applicable.
Water solubility <1%
