Solid-Liquid Separation and Filtration

Why do We Use Perlite Filter Aid in Solid-Liquid Separation and Filteration?

When the filter slurry contains extremely fine particles, filter cakes with fine pores are formed on the filter medium, or the pores of the filter medium are blocked, making filtration impossible. In addition, when the filter slurry contains viscous, gelatinous, or highly compressible particles, the formed filter cake has a high resistance to the filtrate. At this point, another solid particle that is hard and can form loose filter residue can be added to the filter slurry, or it can be made into a paste and added to the filter medium to form a more loose filter cake, allowing the filtrate to flow smoothly. This solid particle is called a perlite filter aid.

Functions of Perlite Filter Aid:

The function of filter aids is to reduce filtration resistance, improve filtration speed and clarity, and extend filtration operation time. Filter aids should be chemically stable, insoluble, hard, and irregularly shaped fine particles, which can form loosely structured and almost incompressible filter cakes.

The application of perlite filter aids in the food industry: edible oils, citric acid, enzyme preparations, agar, carrageenan, gelatin, soy sauce, vinegar, beer, wine, syrup, beverages, fruit juices, etc

Applications for Perlite Filter Aid:

Paints/Coatings/Textiles: Waxes, Oils, Varnish, Gums, Shellac, Paint.

The Usage Method of Perlite Filter Aid is as Follows:

1. Mix the perlite filter aid and filter slurry evenly before filtering, so that the filter aid forms porous and loose filter cakes on the pre-coating. After continuous filtration, a clear solution will be obtained. This method is suitable for substances with relatively low solid content, viscosity, and gelatinization in the filter slurry, and the use of filter aids should be controlled between 0.1 and 0.5%.

2. After mixing the filter aid with clean water, it is fed into the filter machine. The filter aid will accumulate and fill the filtering space, forming a pre coating, and then the filtering operation is carried out to maintain a relatively stable speed. As the amount of filter aid increases, the filtering speed increases, but the amount of filter aid used cannot be increased excessively. When using filter aids, we should consider increasing or decreasing the dosage of filter aids according to the actual operation situation.

3. After the filtration cycle ends, continue to extract the residue from the filter cake by compressing air, disassemble the filter machine, and clean the filter plate.