Asphalt Emulsion Production. An asphalt emulsion is a dispersed system which consists mainly of water and asphalt. One substances is dispersed as droplets in the other.
Asphalt is pulverized using special devices, such as colloid mills, also referred to as dispersers or homogenizers.
In the general case, the asphalt emulsion production process using a colloid mill is as follows. At the first stage, asphalt is pulverized. The forces in the flow turn the spherical droplets into cylinders. If the ratio of the length and diameter reaches a certain value, the droplet divides into two parts: small and large. The process continues until the sizes of the large and small droplets are the same, which usually occurs at the size of 0.01 micron.
The reverse process is also possible, that is, coalescence of asphalt droplets, which is rather undesirable. To prevent this, another component is used: a surfactant emulsifier, which concentrates on the boundary between water and asphalt. The emulsifier attaches itself to the droplets of bitumen creating a protective layer separating the droplets.
Since the layer must be strong enough, the acidity of the water phase must be kept within certain limits. This is achieved by adding chlorine acid.
Most road construction operations use cationic asphalt emulsions, due to good interaction with stone. To make cationic emulsion, several operations are performed:
- supplying asphalt from storage, heating and, if necessary, dehydration;
- preparation of water solution of emulsifier;
- production of emulsion by mixing the asphalt and the emulsifier water solution;
- storage and shipment of the product;
- heating and maintaining the temperature of asphalt and the emulsifier solution.
GlobeCore offers the UVB-1 units, simple in service and operation, which can produce high quality asphalt emulsions, which fully meet the ASTM D 2397-98 and D977-98 standards; the production capacity is 1 to 32 m3/hour.
The equipment can produce consistently high quality emulsions regardless of the initial asphalt quality. All types of emulsion can be produced: CRS, CMS and CSS-1,2, as well as anionic emulsions, including subtype h.