Making useful products from used, dirty plastic feed stock

Great Idea! Start with <harmony1.com> or Google 'plastic recycling'.

Thank you, for taking the time to read my inquiry and to provide a reasonable point in the right direction.

Fine regards,

j peranteaux

Good luck you are gonna need it. Black film plastic sheeting is already heavily 'post consumer' polyethylene. Soil particles and plant yuk are very detrimental to recycling to film products. It is all but impossible to remove enough of the 'dirt' to enable thin wall molding of the molten resin. So , making thick section moldings/castings has to be 'the market', and BLACK is the only color you can make from black plastic sheeting. The black pigment is carbon black and is dissolved in the plastic and cannot be removed from the melt.

You can not clean up the melt enough to make any food or beverage container or retail packaging.

Great comments, and right along my own mental track, thank you!

Yes, the goal would indeed be black, solid objects, not intended for contact with food, etc.

Now, any ideas on the equipment needed to pursue this market?

Best regards,

j. peranteaux

You will need an extruder to reprocess the sheeting also a mold and or a nozzle to extrude the shape you will need. You will have to know how many pounds per hour you will be running thru the extruder.

In Zambia in the early seventies we recycled most of the plastic waste that we generated in the extrusion and injection lines. Recycled PVC with sufficient virgin material didn't produce too many holes in the hose pipes, and the pe was similarly cleaned, ground up at minor cost to the eardrums, mixed with virgin and re-extruded and then possibly pelletised before producing household items like bowls and ten litre beer cups.

The pe was no good for the film extruders, but we did start taking in clear film from dry-cleaners for the other products.

Hello IPERANTEAUXM

I appreciate your enthusiasm shown in converting plastic wastes.It seems you are serious on a production project.I too had tried a lot of products on ETP sludge conversion products.My views are with respect to cautioning you.

1]Our contention and motive may be good,people even may say 'good idea,but non committed to any implementations.

2]If you are trying on your own capital,prefer funded activity and find customers to accept your product.Can it be an effective cost effective substitute to fresh market products?

3]High cost machines,energy involvement could bother cost of product.

4]Go for some low cost crude methods,multi waste composites formations,evaluate performance,possible certifications,trial implementations and proceed.

5]Do some practical low cost product R&D and proceed.

Best wishes

A Plasma Gasification System can turn that plastic into paving material (looks like black obsidian), water, syngas (it will burn), and electrical power (if you use a turbine). These are being installed in major cities around the world. Japan has two giant ones in operation; Florida has one being installed, Long Island is supposed to be getting one, and the US Army has used one for years to get rid of gasses from warfare experimentation.

Westinghouse is one company that makes them.

It is time for California to start using these! Landfills have to be ended soon.

I applaud your efforts and offer a possible alternative, or at least something to consider. Remember that many plastics, rubbers and resins are not compatible with each other due to melting points and additives and a series of other properties. Some may have degraded past being meltable.

Some posts assume that typical processing equipment should be used (extruder's, blow molding, calenders) I would suggest that you consider a crude heated press.

I saw one device taking used soda bottles (PTFE), scrap pipe (PVC), milk bottles (Polyethylene) and other packages (polypropylene), grinding and mixing the flakes to a granular blend.

The solid blend was put into a press and heated and squished into a shape. That week the shape about 30"x30" was a flat square shape with a 3-4 inch lip around the edge. His design was to replace air conditioner pads at home sites. Instead of forming and pouring a patio, these were set on the ground or a sand mound. It was not very pretty and some of the chips were not melted and fused but it appeared to have overall strength and stability. I do not know how he determined the pressure or temperature but suspect it was trial and error. The owner indicated he had many shapes, like your fence posts that he planned on producing.

If it is an unusable mix, there may be offgrade virgin material (cheep) added to bind it.

He may be eligible for some grant money as well.

The major problem will probably be getting the plastic clean enough to use.

If it is shredded, then cross shredded (so it is in fairly small pieces), mixed with detergent and washed thoroughly (perhaps best tumbled, with suitable baffles to act as lifters and increase the washing action - much like a clothes dryer), the dirt should come off into the froth or fall out in your water sump.

As there is a sizable density difference between the dirt and the PE, once they are detached from each other, it shouldn't be too hard to separate them.

Once your plastic is washed, cleaned and dried, it can be roughly melted and the solidified "mess" granulated.

It would probably be best to remove the granules, or even the shredded plastic before washing, to a central plant where it could be made into various items.

Rotary molding would probably be a good process to use. It can be used for comparatively thick walls, is versatile and cheap to set up. (Most PE water tanks are cast this way).

The shredding, scrubbing and dirt separation could be done on site, but it may be better to simply shred on site, press into bales for transport, then remove to your main plant for the rest of the processing. That way, the process water can be extensively recycled, whereas on site there may be problems with disposal, depending on how picky the local farmers and EPA people are.

Good luck. We need more proposals like this to reduce and re use our wastes.

There are some good ideas coming forward. I like the crude "heat and press" idea most so far. This could cope with mixed quality material and a significant amount of contaminant (both soil and plant material).

Maybe you would need to increase the plastic proportion by addition of other post consumer plastic material (soft drink containers and such)

Recently I have seen seating made using "boards" that were rotomoulded from reprocessed material and also "treads" that are interlocked for beach access across sandy dunes to reduce erosion. The black pigment assists in the UV stability of the parts made.

I wish you well on the venture.

There is a process used for PVC extrusion where high percentage regrind, short glass fibers, contaminated scrap, etc. is extruded (the contaminants actually add strength), with a thin layer of virgin material co-extruded onto the surface serving as the "grease" through the die, and providing a high quality finish. Perhaps this process would apply to make thick-wall round and/or squared tubular profiles suitable for applications such as fence posts and rails.