According to the kinds of stones, the aggregate can be classified into many kinds, such as basalt aggregate, granite aggregate, limestone aggregate, river stone aggregate, cobble stone aggregate, sand stone aggregate and slate aggregate etc.
According the aggregate heavy degrees, the aggregate can be classified into coarse aggregate and fine aggregate.
Fine aggregate: the grain size is below 4.75 mm, also called sand. According to the source, there are natural sand and artificial sand. The natural sand is the rock particles whose grain size is below 4.75 mm, formed by natural weathering, potamic transport, separation and stockpiling. The artificial sand is the general terms of mechanism sand and mixing sand that go through the soil removing .
Coarse aggregate: the grain size is above 4.75 mm, also called rock. The common coarse aggregate are gravel and pebble. The gravel is the rock particles whose grain size is above 4.75 mm, formed by the natural rock or river stone crushing and sieving.
Aggregate product line equipment
The aggregate production equipments mainly consists of efficient crushers, such as Jaw Crusher, Impact Crusher and cone crusher. There are other auxiliary equipments, such as storage bin, vibrating screen, feeding machine and belt conveyor.
Some aggregates need auxiliary process, including washing, swirling sand washing machine and rotary screen. The main purpose is to make the final products more clearer. Thick powder separator and dust-cleaning apparatus can be equipped if using dry production process.
Aggregate production processing
Material taking: through blasting, the qualified rocks are fractured into pieces for crushing.
Conveying: after blasting, the stones are transported to the broken factory by tip lorry or belt conveyor. Or the conveying is the internal materials input process in each links.
Crushing: Using all kinds of crushers or rod mill or Ball Mill to crush the materials so that the materials will be smaller to meet various specifications demands.Crushing is the most important link in aggregate production process and is also where the aggregate production equipment fully plays its role. In addition to various types of crusher and auxiliary equipments, the VSI5X new sand machine researched by SBM Machinery is the necessary machine for producing the quality sands.
Screening: Sorting in the production process. Through various specifications of vibrating screen, the qualified materials are selected out then transported to the corresponding materials heaps. The unqualified materials are sent to crushers for next crushing.
Drying: Drying the aggregates which size and shape are qualified, in order to make the moisture content reach to relevant requirements. Generally speaking, the coarse aggregate needs natural drying. The fine aggregate(coarse sand and fine sand) needs dryer equipments.
Storage: The produced aggregates, which meet all kinds of specification requirements, are stored separately. For the different requirements for containing moisture and operating and environment condition, the open storage can be used and the storage bin or vertical shaft can be used for storage.
In the six working procedures, conveying, crushing and screening often are repeated. The processing flow can be summarized as screening repeated, crushing repeatedly and directional conveying.
Aggregate is granular loose materials whose total volume is the 60% ~ 80% of concrete volume. As the main raw material of concrete, the aggregate plays a role as skeleton or support in the concrete.The aggregate plays an important role in building. When mixing the materials with water, the cement will be thin paste after mixing. If the aggregat is not added, the cement will not be able to shape and not available. So we can say that the aggregate is very important.