Pumping Titanium Dioxide
Titanium dioxide solution is a slurry of titanium dioxide powder and base/carrier fluid.
The powder itself is poorly soluble and requires constant agitation. It is a silt/sand-like suspension which will sediment should the agitation/mixing cease. Most commercial uses are approximately 70% solids.
Titanium dioxide has a high S.G, stable and is non-flammable. As a fluid it is extremely abrasive.
Applications
- Traditionally, titanium dioxide has been chiefly used for its brilliant white colour – even being referred to as ‘the perfect white’.
- The largest use of titanium dioxide is in paints, varnishes, inks and dyes for white colouring, opacity and increasing the resistance to the environment and sunlight.
- In the production of paper, titanium dioxide is used to increase the strength and opacity of paper. The common alternative is china clay which produces a weaker and more transparent grade of paper. By using titanium dioxide it both provides strength and reduces the weight of the final paper product.
- In plastic and rubber products, the addition of titanium dioxide increases the strength of moulded products, car tyres and minimises degradation caused by environmental conditions, particularly UV rays.
- Due to its photo-refractive qualities, titanium dioxide is used as a catalyst for UV disinfectant during the treatment of water. For the same qualities it is also used in the coatings for photovoltaic cells and in semi-conductors.
- Titanium dioxide is also a major ingredient in sunscreen.
Pumping considerations
Titanium dioxide is usually dosed into a process or mixture.
The chemical is expensive and the exact blend of the product is crucial for product quality and consistency. The mixture is supplied in a concentrated manner and is often mixed/diluted prior to being dosed.
Due to its abrasive nature and high S.G., it is recommended using a peristaltic pump. The nature of the hose and rotor positive displacement principle means that the abrasive slurry will have no effect. As the hose is compressed by the rotor and the fluid is ‘pushed’ through the pump there is no frictional wear. The speed of the pump is directly proportional to the flow rate so the accuracy of the chemical delivery is precise.
A peristaltic pump can easily handle the S.G. and also provide excellent suction lift.
In hazardous areas, a non-metallic AODD pump will also provide an excellent pumping solution and is commonly used by electronics manufacturers for recirculating highly abrasive slurries.
The materials specified depend on the type of solvent/carrier fluid for the powered chemical. PTFE elastomers are compatible with most solvent types as well as being highly resistant to abrasion.