Aggregate recycling apparatus having air circulation type foreign substance and fine particle separation means, and method thereof

Abstract

Disclosed is an aggregate recycling apparatus having an air circulation type foreign substance and fine particle separation means which directs a blast of air, circulated in a dry state, toward waste having passed through a crushing process immediately after the crushing of the waste and removes fine particles and foreign substances using a cyclone, thereby removing dust generated in the course of separating and screening the waste, and a method thereof. The aggregate recycling apparatus includes a crushing device for crashing waste, an air circulation type fine particle and foreign substance separation device for directing re-circulated air to crushed products received from the crushing device, scattering fine particles and foreign substances and collecting dust in a cyclone, an air conveyor for conveying crushed products deprived of the fine particles and foreign substances, and a double vibration screen for screening the crushed products received from the air conveyor.

1 . A method for recycling aggregate comprising the steps of:
 primarily removing earth from waste in a vibration hopper, putting the waste into a primary crusher selected from a group comprising an impact crusher and a jaw crusher, crushing the waste, discharging the crushed products, separating metallic material contained in the discharged crushed products using a magnet installed above a discharge conveyor, and discharging the resultant crushed products on the discharge conveyor;
 directing air, circulated through a forced air flow passage to the crushed products dropping from the discharge conveyor so that the crushed products can be scattered into an air conveyor box installed above an air conveyor depending upon specific gravities thereof, separating fine particles and foreign substance using suction force of a cyclone, and discharging crushed products, which drop while overcoming the suction force of the cyclone, to a screening device by the air conveyor; 
 sucking crushed products, scattered into the air conveyor box, into the cyclone depending upon specific gravities and sizes thereof by a pressure reduction device of a blower, separating fine particles and foreign substances, discharging the sucked fine particles and foreign substances through a discharge conveyor positioned below the cyclone, and forwarding air rid of the fine particles and foreign substances so that the air can be reused; 
 repeatedly re-circulating air sucked by the blower through the forced air flow passage, discharging a predetermined amount of air into a chamber and a filter which are installed in the middle of the forced air flow passage so that fine particles and foreign substances which are not removed in the cyclone can be removed and thereby the predetermined amount of air is purified and then discharged to the outside to create negative pressure in the air conveyor box to thereby prevent dust from being raised and enable air to be repeatedly used; and 
 conveying crushed products, which drop while over coming the suction force of the cyclone, through the air conveyor installed at a lower part of the air conveyor box so that the crushed products can drop onto a double vibration screen at an end of the air conveyor to be screened into three types of aggregate. 
   
   
   
       2 . The method according to  claim 1 , wherein, in the step of screening the crushed products into three kinds of aggregate on the double vibration screen, crushed products having a small size of 0.3˜8 mm are discharged onto a discharge conveyor disposed below the double vibration screen to be used as recycled sand, crushed products having a medium size of 8˜25 mm are discharged onto another discharge conveyor disposed at one side of the double vibration conveyor to be used as recycled gravel, and crushed products having a large size of no less than 25 mm are put again into the impact crusher through a return conveyor disposed at the other side of the double vibration conveyor, or are put into a secondary crusher, such as a cone crusher or a vertical type impact crusher, to be crushed therein to thereby continuously produce recycled sand and gravel.