In the processing of powders it is essential that the powders flow freely and in a controlled manner. The cost and inconvenience caused by poor flow or caking are well known to those used to processing with powders. Powders that flow poorly during manufacture adversely affect process operability and efficiency. Those that "cake" during storage or transportation often are the cause of subsequent customer complaints. Flow problems can be caused by one or more of the factors below:
- Particle size ad shape
- Surface activity
The solution can be the addition of a free flow aid that can overcome these problems. PQ Silicas free flow/anti-caking aids allow smooth flow control throughout the production process, are added at low levels, do not need high shear equipment and can be added to low energy mixers. They are pure, inert, GMO free and approved for use in food and animal feed.
The specific grade required will depend on each customer process, please contact firstname.lastname@example.org
to discuss your individual requirements. Several typical uses are discussed below:
Milk and cream powder substitutes, vending machine powders, grated cheese, sugar and powdered food flavours.
In most circumstances, Neosyl GP is recommended. The actual level of GP required to achieve the flow properties wanted varies from application to application, but the table below gives some examples.
| Pre-mixed gravy powder
||Stuck in container
| Dried salt
||Caking in the package
||In line addition
Neosyl TS is somtimes preferred with a smaller size, tighter particle size distribution and resistance to overmixing. It has been shown to give better flow rate and reduced flow variation in some formulations.
Microcal ET is used as the additive of choice on grated cheese. It can be used on any type of cheese but is used especially with cheeses such as Mozarella. High bulk density, coupled with small particle size, aids distribution of the anti-caker. Unlike some competitive products, such as microcrystalline cellulose, after a period of time (approx 24 hrs) the Microcal cannot be observed although it is still effective. Microcal has the advantage over potato starch in that is has no effect on the subsequent processing of the cheese.
Microcal is also the product of choice as a carrier/free flow aid in emulsifiers for the food industry.
Neosyl AC is recommended for processes where the bulk density of the finished product is high and critical. It is an effective additive in turbulent air mixing conditions as it separates from the other ingredients less easily than other agents. Pore size and number are such that the moisture uptake is high and the silica retains held moisture. This is an important aspect when considering applications where caking may be caused by high moisture vapour levels, especially at elevated temperatures. One such an example would be powdered drinks for vending machines.
Animal Feed Applications
Calf milk replacers, mineral salts, dried whey, urea and pet foods.
Detergents, fire extinguishers, pesticides, fertilisers, blowing agents and chemical powders.
Alusil ET can be specifically used in the field of inorganic iron oxide pigments. The flow of these pigments in mechanical handling systems can be poor. The addition of Alusil ET, at approximately 1.5% to the pigment gives an improvement in flow properties, both rate and consistency.
In most powder detergents, Neosyl GP is recommended as the anti-caking agent of choice. However, in some detergent systems the use of silicas as a free flow agent is precluded owing to the high pH of the system, (silica is affected by systems over about 10.5). Alusil has a high pH itself (11.0). It finds use in these detergent systems as a free flow/anti-caking additive.
Neosyl AC is recommended as a filter in specialised phenolic resin systems.