Green mine dry sand making technology has become increasingly popular in recent years. Tower-type sand making is an advanced form of dry sand making, and stone powder control is critical to finished manufactured sand quality and output. Various classification equipment is widely used for this purpose, including Centrifugal Air Classifier, which playing a vital role; proper use of a powder separator greatly improves manufactured sand quality.
Four Forms of Stone Powder in Manufactured Sand
(1) Free Powder
Stone powder particles are unbonded, unadsorbed, and free-moving under wind and gravity. This type is easily separated by an Air Classifier, whose high-speed airflow quickly carries away free stone powder for preliminary sand purification.
(2) Agglomerated Powder
Fine stone powder particles cluster into large agglomerates via adhesion and polymerization. A Centrifugal powder separator is essential for handling them—even high-performance models need optimal parameters to separate agglomerates, though a well-adjusted Centrifugal powder separator can break partial clusters and improve removal efficiency, outperforming conventional equipment.
(3) Adhered Powder
Stone powder adheres to coarse sand surfaces. A Centrifugal dust separator is ideal, as its strong centrifugal force overcomes adhesion. It easily removes powder from smooth sand surfaces and achieves partial separation from rough surfaces by adjusting airflow and centrifugal force.
(4) Interstitial Powder
Sand particles have 10-100 micron gaps filled with stone powder, the tightest adhesion form. An Air Classifier, with precise airflow control, penetrates gaps to remove embedded powder without damaging sand grains, ensuring quality standards.
Centrifugal Air Classifier to Reduce Powder Content
In sand manufacturing, the powder separator separates excess stone powder from useful particles. The Centrifugal Air Classifier, a high-efficiency powder separator, is widely used in tower-type plants, combining centrifugal and airflow separation for greater efficiency than ordinary powder separators.
Its working principle: Air and powder form a gas-solid two-phase flow; a rotating distributor disc and high-speed airflow impart differential centrifugal force to separate coarse and fine particles, which are then recovered separately. The Centrifugal Air Classifier's structure ensures stable, efficient separation, while the Air Classifier accurately sorts useful particles into finished sand.
Installation layouts include raw material and finished product classification: a Centrifugal dust separator pre-removes stone powder from raw materials, while a Centrifugal powder separator purifies finished sand. The Air Classifier, Centrifugal dust separator and Centrifugal powder separator all require stable airflow, with moisture content critically affecting efficiency.
Above 5% feed moisture, classifier efficiency (including powder separator and Centrifugal Air Classifier) drops sharply. At ~2% moisture, the Centrifugal powder separator, Centrifugal dust separator, Air Classifier and Centrifugal Air Classifier perform optimally, achieving a 60%–70% sand yield.