Natural sand is naturally occurring rock particle with a grain size below 4.75 mm through the artificial mining and screening processes, including river sand, lake sand, mountain sand, desalination sea sand (also called washing sand), but not including soft, weathered rock particles.
The sea sand is usually strictly prohibited to use in architectural decoration field. Although sea sand is clean, it contains high-level salt content that will have a bad impact on the quality of construction projects. It mainly to see whether the sand contains small marine shells to distinguish whether it is the sea sand.
Mountain sand has a relatively rough surface resulting a good effect for cement attaching, but the components of mountain sand is complex and most of them contain soil or other organic impurities.
River sand is a natural stone generated after a long-term repeated collision and friction under the water force in the natural state. It is one type of non-metallic ores with a complex components, a certain smooth surface but more impurity contents. After the drying and screening processes, river sand can be widely used in a variety of dry mortar production, for example,the insulation mortar, bonding mortar and surface mortar are use washing, drying, grading river sand as the main aggregates. The strength is similar to the mortar made by quartz sand. Therefore,the river sand has an irreplaceable role in construction and decoration fields.
Manufactured sand is a general term of artificial sand and mixed sand through the soil removing process.
Artificial sand, also known as machine-made sand, is the rock, mine tailings or industrial solid waste particle with below 4.75mm grain size through the soil removing, mechanical crushing and screening processes, but not including soft, weathered rock particles.
The quality of manufactured sand (mainly refers to the artificial sand); largely depends on the sand making equipment and of course the raw materials and production technology, etc. In terms of equipment, sand manufacturing machine can be differently classified in accordance with the crushing principle such as jaw crusher, cone crusher, gyratory crusher, hammer crusher, gyradisc crusher, impact crusher, roller crusher and vertical shaft impact crusher. Considering the quality of the grain size of the end product, rod mill sand maker, hammer crusher and vertical shaft impact crusher can get the better quality m-sand than impact, gyradisc and cone type crusher. The quality of manufactured sand produced via jaw, roller and gyratory type crusher is worse than crushers mentioned above. There are several common manufactured sand production lines in construction industry, for example, rod mill sand making machine + sand washing machine. In order to reduce the loss of fine sand, the sand manufacturing line is usually equipped with one set fine sand recycling machine. This production process can produce high quality manufactured sand, but its cost is higher than others because it adopts wet sand making technology that has a strict requirement for water resource and a high volume water consumption; There are some small-scale construction sites using hammer crushers. Hammer crusher has the features of high productivity, high crushing ratio, simple structure, easy maintenance, etc., but its main spare parts like hammer head, grate head, liner plates, rotor disc are easy to wear. Additionally, if the raw materials is harder, the sand grain size and gradation will be hard to control so as to effect the concrete homogeneity; In recent years, with the production technology vertical shaft impact crusher developing and improving, more and more user choose VSI sand maker to produce high-quality manufactured sand. The sandstone corners are collided and ground in the crushing chamber, so that it can produce good grain size and continuous gradation manufactured sand. What’s more, VSI adopts the dry sand making technology, so it has nearly no special requirement for the water resource, which can greatly reduce the production cost.