Construction Waste Process Design II
In the last article, we mainly introduced crushing& screening design method for construction waste processing. In this article, we focus on separation& impurity-removing design method.
Separation& Impurity-Removing Design Method
The crushing of construction waste generally includes coarse crushing and fine crushing stage. But if we do not clear the impurities and sundries in the construction waste as much as possible, it will be more difficult after crushing. So before crushing, we need firstly remove the impurities out. The main separation& impurity-removing methods are:
1. Air Classification
Air classification adopts air as the separating medium. Under the effect of airflow, it separates the solid waste according to the specific gravity and grain size. Based on the direction of airflow, air classification can be divided into air suction and air draft. Air suction classification method works like dust collector, separating the impurities by negative pressure. Air draft classification method blows the light material out from the aggregates by blast airflow.
2. Magnetic Separation
The magnetic materials in construction waste are mostly concrete iron in concrete building structure. When the buildings are dismantled, the waste concrete iron mixed in the concrete blocks need to be magnetic separated after crushing. The commonly used magnetic separation equipment in construction waste processing are cross belt magnetic separator and permanent drum magnetic separator.
3. Hydraulic Flotation
There are waste plastic, wood, paper and air-entrained concrete mixed in the construction waste, and their specific gravity is smaller than water, so we can separate them with concrete and brick according to the floatability.
Construction waste processing is a very complicated procedure, and customers should choose suitable design and proper equipment according to the component of the construction waste and the local working site condition.
