As the swift and violent development of plastic industry, and the constant growth of plastic rubbish, useless old plastic second birth uses a trade increasingly arisen. But because plastic breed is various, applied field is extensive, reclaiming so in the process, what very much different sort reachs color is plastic was mixed one case. The plastic function of different breed and treatment condition are different, the to treatment and application impact after mixing is very big, be in so useless old plastic reclaim undertake in the process grading it is indispensable link.
One, grading purpose
Reclaim there basically is 3 on plastic mart big grading demand:
1. Eliminate is plastic medium metallic;
2. To different color plastic undertake classified;
3. Of divisional and different sort plastic.
2, grading method
Current, useless old plastic and grading normally cent is mixed for handiwork mechanical and grading two kinds. Preliminary and grading basically choose vibrating separator, turn beat, magnetic force is grading machine, wind-force is grading depart of machine; material can use all sorts of material to pledge grading equipment and device, include density, electrostatic, difference in temperature, infrared ray, optical camera and X- ray divide into equal parts to choose equipment.
1. Handiwork is grading
Hand workpoint is chosen even if be in through will be being mixed artificially useless plastic the impurity in, and the plastic division of different breed is separate. Take time of this kind of method is arduous, efficiency is low, but investment is small, easy begin, the operation is agile. Hand workpoint chooses measure to be as follows:
① eliminate metal and metalloid impurity, the useless plastic products that eliminate quality drops badly.
② presses goods first, if the goods such as filmy, bottle, cup, leftover material undertakes classified, classify different plastic breed according to differentiating a law again.
③ mixes the useless old plastic products of afore-mentioned classification by color depth again quality is grading.
2. Mechanical and grading
Can pass magnetic separation, density grading, centrifugal depart, floatation depart, wind screens electrostatic and grading, grading, infrared ray grading, take a picture grading with difference in temperature grading etc the method is grading. Infrared ray and take a picture grading, also but attributive smooth credit picks a way, be in recent years achievement of digital technology development is in useless plastic reclaim the new application in second birth.
① magnetic separation
Magnetic separation is the method that uses metalloid of iron of magnetic body depart, main purpose is eliminate interfuse is abandoned old plastic the metal such as medium iron and steel is drossy foreign matter, because these are finely,steel iron filings uses manual and grading method eliminate not easily.
② density is grading
Density is grading it is to use different and plastic have different density this one property has grading method, specific means is will jumbly abandon old plastic in be being put into some kind to have the solution of certain density, next the basis is useless old plastic the condition of ups and downs in this solution will undertake grading. Density is grading methodological advantage is simple and easy and feasible, should choose to make up a kind only or a few kinds of solution can have large quantities of amounts grading, and the man minute that avoided loaded down with trivial details chooses; the plastic density that its defect is some sort is very adjacent, accordingly, the detached thing that should achieve tall purity is more difficult.
3. Photoelectricity is grading
This law is to use different sort plastic different to the absorptivity of X ray undertake depart, do not contact, do not destroy plastic products itself, mobile edge is detached by the side of content be detectinged. Differ according to ray action mechanism, smooth credit chooses a law to be able to be divided for X ray depart and fluorescent X ray depart. X ray depart is will projectile X ray change becomes telegraphic name, judge should the plastic products of purify, with compress air to blow its fall undertake depart. Depart of fluorescent X ray is the fluorescent X line that by illuminate X ray thing be detectinged produces, via prismatic and junior travel the ration of bases is judged.
4. Colour separation process
This method is the technology that has depart according to colour, it is to make be detected the color of content adopts several filter look implement hind, be worth each different brightness conversion into electric current and with this in group, combination of color identifying device and material depart device, classics optics discerns plastic bottle after the color that wait, blast blows discolor bottle, this law basically applies at the plastic products of color existence difference.
5. Infrared ray is grading
Infrared ray is grading can divide for close infra-red and grading with infrared ray grading. Close infra-red and grading principle is to use irradiation of close infrared ray by grading the material when content is presented character those who go out is different absorb degree to undertake grading. Close infra-red and grading the sorting that can be used at plastic products.
The principle with grading infrared ray is the identifying that the object presents to issue different reflection character to undertake an object with visible light inside the infra-red wavelengh limits of make choice of. Infrared ray applies at plastic grading, can distinguish 6 kinds plastic, include PET, HDPE, LDPE, PVC, PS, PP, energy standard rate can be amounted to 100% .
6. Groovy wind-force is grading
Groovy wind-force is grading be will classics those who smash is plastic put in grading the eject inside device, wind from transverse or converse inbreathe, use different and plastic have grading method to the obstruction of air current and self-prossessed join forces difference. The degree of finish as a result of the granuality after smashing can affect grading result, the granuality degree of finish after so this law asks to smash is even, and granuality degree of finish is even the main factor that degree is effect of influence selection by winnowing or wind. In addition this law also can be used at grading and plastic in the cobble of interfuse and sand, but reach fractional figure approximately to density irregular plastic and detached effect is poorer.
7. Wind- driven table is grading
Wind- driven table is grading it is wind- driven and grading special kind, its principle is to use the vibration of bed face and ascendant air air current to make grain presses density statified. Particular procedure is from poriferous vibration bed below blows ascendant air to flow, the particle size distribution with bead big or old way is in density lower level, and the particle size distribution with bead small or small way is in density superstratum, below the attrition strength effect in oscillatory acceleration and bed underside, lower level heavy grain moves to declining oscillatory bed upside; is contrary, the attrition force between heavy grain of superstratum light grain and lower level is small, motion arrives a side with oscillatory inferior bed, make thereby both get grading.
8. Electrostatic and grading
Electrostatic and grading it is to use all sorts of plastic and different triboelectricity function to have grading method. The polarity when different and plastic attrition is electrified is decided by live performance. Use electrostatic undertake grading, the useless plastic need to a variety of lump for many times grading, because every pass the voltage of preelection set,can divide only single out a kind plastic.
9. Difference in temperature is grading
Difference in temperature is grading it is to use plastic material to have grading method to the sensitivity of temperature, have microtherm and high temperature different approach.
Microtherm is fragile change grading the law is to use all sorts of plastic have those who differ is fragile change temperature to have grading method.
High temperature granule is grading and plastic granule can happen to change below constant temperature, because,this is plastic lift along with temperature, drawing function and percentage elongation raise the appearance of generation, but different plastic granule changes function to also differ, use this character to undertake plastic grading. Plastic granule changes character to be able to classify as follows:
① can the plastic material that microtherm granule turns includes PE, PP and epispastic PS to wait.
② can the plastic material of microtherm pulverization has PVDC.
③ can the plastic material that high temperature granule turns includes PVC of PET, horniness and plating aluminous film.
④ high temperature also cannot the plastic material that granule turns has hot solid sex plastic.
3, home is main and grading the enterprise of equipment
1. Tao Lang is grading technical limited company
2. Dongguan A Mo Si is special limited company of environmental protection science and technology
3. Limited company of technology of sorting of double be an official
4. Limited company of science and technology of photoelectricity of Hefei peaceful standing grain
5. Hefei is beautiful inferior photoelectricity technology Inc.
6. The luck in Shenzhen city is small inspect photoelectricity limited company
7. Limited company of science and technology of Mu of Lai of Shenzhen city general