re-use of waste foundry sand by shaun lindfield – safety & environmental engineer precision...

Re-Use of Waste Foundry SandRe-Use of Waste Foundry SandBy Shaun Lindfield – Safety & Environmental EngineerBy Shaun Lindfield – Safety & Environmental Engineer

Precision Disc Castings LtdPrecision Disc Castings Ltd

• Employees – 198

• Turnover £24 million

• Capacity 50,000 ton castings/year

• 5-6 million brake disc castings/year

• 90% ventilated discs & 10% solid discs

• OE & Aftermarket Customer base

Precision Disc Castings LtdLeading the world in brake disc technology

Who are we?

We are a cast iron foundry based in Poole, Dorset that manufactures brake discs for the automotive industry.


How do we make brake discs?

Melting – We melt 1500T per week of scrap material in 4 medium frequency induction furnaces @ 1,530oc.


Moulding – We make approx 65,000 greensand moulds each week out of sand, clay, coal dust and water on each of our 2 Disamatic Moulding Lines



Core Making – We make approx 105,000 sand cores per week, using virgin sand (from the Congleton area in the UK) resin and a catalyst in one of 7 cold box core machines.



Casting – We add core’s to each mould and then pour molten metal into the mould using a laser guided pouring system on our Calamari Holding Furnaces.



Fettling – We fettle/grind approx 110,000 castings per week ready for dispatch.



The Problem

Because the material can’t be economically reclaimed for core making we have approx 275 Tonnes of material (equivalent to 105,000 cores sacrificed in the process) excess in the sand system each week, which must be removed.

All the materials used in the moulding/casting process can be re-used within our own sand system, but they can’t be re-used for core making.

There is also 40 tonnes per week of dust extraction fines that have to be dumped to Landfill.

A further 100 tonnes per week of material that is natural spillage from the moulding lines goes to landfill.


The Solution - Past

In 1996/97 PDC formed a partnership with Tarmac Southern Ltd, which meant that most of the excess waste greensand would be used by Tarmac manufacture asphalt.

This original partnership meant that PDC would send the excess greensand to Tarmac for re-use rather than landfill. This was approx 4,000 tonnes/year and saving £59,000/year.

PDC made modifications to their plant to allow sand batches to be dumped direct into rigid lorries rather than onto indirect production line belts & skips.

Tarmac also made some modifications including building a covered storage bay.


The Solution - Current

PDC and Tarmac’s partnership has continued to flourish since 1997, which has allowed PDC to provide Tarmac with more material for re-use.

As more material became available, Tarmac increased the number of sites using PDC’s surplus sand to include three of their South Western asphalt plants, with a fourth coming online during 2008.

PDC have increased the amount re-used by Tarmac by: -

• Installing blow over units from the dust extraction plants

• Installing a Pre-conditioning plant.

• Installing a Sand Reclamation belt



By installing these afore mentioned items of plant PDC have increased the amount of material re-used by Tarmac from 4,500 Tonnes/year to 12,500 Tonnes/year.

Comparison of Quantities of Material Re-used by Tarmac

0

2000

4000

6000

8000

10000

12000

14000

2000/2

001

2001/2

002

2002/2

003

2003/2

004

2004/2

005

2005/2

006

2006/2

007

2007/2

008

Year

To

nn

es



As a result of this initiative, PDC has managed to save a significant amount of money as shown below.

Cost of Re-use = £8.75 per tonne

Cost of Disposal in 06/07 = £14 per tonne & £80 transport per load

Cost of Disposal in 07/08 = £15 per tonne & £92 transport per load

Year Tonnes Tarmac Cost Disposal Cost Saving

2006/2007 9,165 £80,193 £180,681 £100,488

2007/2008 12,664 £110,810 £273,180 £162,370

As you can see from the above table PDC saved £162,370 through our partnership with Tarmac in 07/08.


The Solution - Future

PDC hopes to further increase the amount of material re-used internally before eventually being transferred to Tarmac for re-use in asphalt.

A pneumatic fines blow over system is currently being installed, which allow approx another 500 tonnes of material per annum to be re-used.

This will mean that Tarmac will soon be re-using 13,000 tonnes of PDC excess waste greensand

PDC will therefore, re-use/recycle 14,500 tonnes per annum of the total 17,000 tonnes of waste generated = 86%.


Summary

PDC and Tarmac’s partnership has gone from strength to strength since its beginnings in 1997.

Tarmac originally took 4,500 tonnes/year in 1997/1998 compared to 12,500 tonnes/year in 2007/2008, giving considerable environmental and economic benefits to them.

This has had a massive positive impact for PDC’s Environmental Performance, compliance with ISO 14001 and economy of operation.

re-use of waste foundry sand by shaun lindfield – safety & environmental engineer precision...

Documents

brake disc castingsyear

brake disc technology

brake discs

brake disc technology

week of material

sand cores

sand system

ventilated discs