Cascade e-ion Liquid Metal Processing Applications - Frequently Asked Questions

Please see below some answers to questions we are asked.

The critical five questions are asked and answered as separate question 1 (a), (b), (c), (d) and (e).

1 (a) How many Cascade e-ion units do I need for reducing dross?

Think of it like a continuous ion generator.  Start with one for a standard 1000lb melter (i.e. add to existing furnace).  The number of ions may be enough.  Later if you need more units they can be added modularly. 

The Cascade e-Ion machine produces and disperses a steady flow of ions.  The ions tend to gravitate to the liquid metal surface just as if it were a gas cover.


This is like having a gas cover only except that that the cover is an ionic 'gas'.  Ions are supplied and they distribute and wane that is why the flow is continuous.


The input for ionization for the Cascade e-ion can be air which reduces dross. Ionic gases are reducing in nature that is why dross is low.    If nitrogen or other gas is required the same units can use them but most operators prefer air as it is lower cost.


The range of DRO models produce 8-35SCFM depending on model.


All furnaces are sealed differently but a comparison is possible.  The user should compare with the volume of nitrogen gas cover they may have alternately used for dross reduction.    Generally speaking keeping a very good level seal when one is paying for a gas like nitrogen is OK but not entirely necessary when just using air like the DRO systems uses for ionization.


1(b)  Is it easy to attach to an existing aluminum or silver or gold melting furnace?


Yes.  If the furnace has a port in the cover, one may generally slip it on.  Or can be threaded.  Please contact.   In particular for separating expensive alloys with low dross is a very good use for the cascade e-Ion machines.  Please consider ROIs.


1(c)  What is the life?


It should be long but depends on the environment. A heavy amount of mechanical vibration is not recommended.  Regardless there is a Never-down policy which assures free early repairs if required and a contained maintainance price. 


1(d)  How much maintenance?


It is like all high quality MHI thermal machines.  Please discuss options with MHI.


1(e)  Should I consider the DRO machines as primary for melting?


The machines are ~10kW i.e at 10 cents per kW hour it will cost $1 per hour to use such machines.  As a very approximate number 1kWhr energy melts about a pound.  We recommend that the DRO machine be add-on as most large furnaces are already configured to melt tonnes of aluminum withou long delays.  For melting old-spent-dross mixed with something like aluminum chip-waste,  it is best to consider a very high temperature furnace. Such recovery methods include melting at a very high temperature which can be easily done e.g. with a MHI batch furnace.  For old spent dross one could use a HT furnace and new seperation methods.



Please contact MHI at [email protected].  DRO additions made to conventional melting furnace-machines is recommended. The DRO is a novel dross reducing machine.  Please note that the power is ~10kW-30kW depending on configuration.  It takes about 1kWhr for melting a pound of aluminum - so the DRO machine even though a significant dross reducer, for large aluminum molten surfaces are not necessarily primary for melting unless this is the power-range you seek.  The 10kW-30kW is transferred very efficiently so it would be a great high speed primary except for the fact that most aluminum melting and holding is not set up for rapid continuous melting feed. Earlier in 1990s the machine was conceived as a primary melter for continuous aluminum melting but this idea of continuous melter was too early for our  furnace manufacturers and most aluminum is melted or held in a batch mode even today.  However it was realized by the Edison Materials TEchnology Institute that the DRO would have significant advantages as an hot-ionic cover because there is no such availability except for the DRO machine for a hot ionic cover.  The ROI from a clean cover for aluminum  is very high indeed and that it where the DRO models fit.

2. Would like to know something about the control systems?

SCR based control systems. Several models available which offer control of energy through power or temperature settings.  In industrial use for 20 years.

3. How does the furnace prevent Al nitride- how do you prevent the interaction?

Temperature is not hot enough for aluminum nitride formation. We have not noticed any nitride formation in the melt or on crucible walls.

4. What is the cost of the Cascade e-ion generator?

You will be surprised at the price and ROI. Of course it depends on the model.  The DRO models are suited for this application  Please contact us for current prices and models.

5. Space limitation, how big can it be scaled up?

This is one of the lowest foot-print devices.  Controls are small and can be remotely located.

6. What if the the coverage is more than one unit can handle.

As units are modular you can easily add more should you require to do so.

7. How does the Al react and behave in the furnace?

Clean and not turbulent at all. Very low dross.

8. Questions about the induction melting numbers, they seem too low.

Please see full details on Aluminum Melting Furnace.

9 . Clarify the ionization, what does it mean?

A technical article is posted on the site. Patents are under issue.

10. What are the power requirements, voltage amp etc?

Again please contact us.  Several voltages are possible.

11. What control system is used?

Same as question 2 above.

12. What kind of seal is required?

No seals. Open to air.

13. How do you introduce the scrap into the unit?

Please discuss with us for scrap.  Scrap can be gravity fed. Other ways of introducing the scrap with a conveyor or screw will be possible. We recommend that you construct the furnace you need and simply add the Cascade e-on generator.

14. How do you seal the chamber and prevent intrusion of O2?

No seal required. O2 is present but is blanketed away by ions.  Metal covers appear shiny. (See technical article).

15. Clarify whether scarp is wet/dry/painted/oil and how to deal with each?

All can be used depending on your existing scrap furnace, sometimes with a pre-heater in the conveyor.

16. What kind of metal temperature is achieved?

Metal is estimated to be about 20-100°C above the meting point in normal melting operations. It depends on your furnace.

17. What do you mean by 'hot zones'?

Space inside the furnace.

18. Scrap size is very important, how much can be in the furnace?

You can continue to use your existing furnace.

19 . Why not a ceramic or graphite felt filter?

The filter material in the two page introduction referred to the filter scrap that comes from a sprue which had metal filters.  The furnace separated the sprue and filter by a melting process.  . No filters are used required for normal melting.

20. Why is a steel mesh filter needed, and the chance of iron impurities?

Same as question 19 above. There is no filter in furnace.  In the example used for the trials the sprue contained a metallic filter.

21. Where does the O2 go or consumed?

Low oxidation because of ionic gas. It is blanketed out by ions.

22. What is the largest furnace been made to?

Mostly use for tonnage furnaces when employed for dross reduction. 

23. Do you lose advantages when you scale up?

Larger furnaces give larger productivity advantage (see benefits). We do not anticipate loss of efficiency or more energy consumption per pound but do anticipate unit cost per ton of aluminum could reduce with less dross.

24. When tap furnace, use tap hole to plug drain.

Furnace can be run continuously or as a pit. These are different configurations both possible. Fan blown. Very gentle. No sound.

25. What is the best furnace lined with?

One can use alumina refractory.  Use FiberFree.

26. What is the affluent seal or is there one, is it completely sealed, vent for gasses?

No Seal.

27. Does it work with solid Al or silver or beneficiation?

You, mean can it be used for heat treating or separation from silver lead bismuth. The answer is yes.

28.  Whether the scalability of the design will allow for melting at rates of about 0.5 - 2.0 kg/s?

This depends on power and configuration. Rapid melting is possible because of the clean atmosphere and very enhanced heat transfer coefficient to the melt. Once again please see the web site for details.

29. What is the energy consumption (overall, including any necessary heat-up, holding time, etc), capital cost of equipment?

For blanketing a standard tonnage (one ton) furnace you should start with one unit. Each furnace is different.  Please review answer in question 1(d).  Please see the Melt Rates table if melting is to be affected.



Copyright © 2005 - 2013