One possible approach might be a patent search, for example in the US PTO database at:http://patft.uspto.gov/netahtml/search-adv.htm
the search: abst/foundry and abst/energy gets 12 hits.
The European Patent database at http:ep.espacenet.com is even larger - and may get many other patents. For example, searching "title/abstract": foundry and "European Classification(ECLA)": F23G7 ("Incinerators or other apparatus for consuming industrial waste,...") gets 5 patents.
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1 Method of saving energy from mill scale consists of supplying satellite furnaces with energy. Inventor: Applicant: HOELTER HEINZ (DE)
EC: F23G7/00 IPC: F23G7/00 Publication info: DE10122538 - 2002-11-14
2 Plant and process for demolishing scrap cars and associated scrap by heat treatment with energy recovery. Inventor: FOGGINI MASSIMO (IT) Applicant: FOGGINI MASSIMO AND BLAAS ANSE (IT)
EC: B09B3/00; B09B5/00; (+2) IPC: B09B3/00; B09B5/00 Publication info: EP0565032 - 1993-10-13
3 Process and device for subsequent treatment and purification of waste gas originating from a secondary aluminium foundry. Inventor: SOMMER HERMANN DR DIPL-ING (DE); SCHLODERER ROBERT DIPL-ING (DE); (+1) Applicant: SOMMER METALLWERKE (DE) EC: F23G7/06B; F23J15/00P; (+1) IPC: B01D53/34; F23G7/06; (+2) Publication info: EP0486759 - 1992-05-27
4 Process for eliminating a combustible material enveloping solid fragments and apparatus for carrying out said process. Inventor: GAILLY CHRISTIAN Applicant: GAILLY FOND SA (FR)
EC: B04C11/00; B22C5/08; (+5) IPC: F23G7/00; F23N1/02; (+4) Publication info: EP0021875 - 1981-01-07
5 Cold set catalyst supply and fume incinerator for a foundry core making machine. Inventor: FLORA LAWRENCE E; DUBOIS BILLY G Applicant: SUTTER PRODUCTS COMPANY EC: B22C9/12A; F23G5/50; (+1) IPC: B22C9/12; B22D27/14; (+1) Publication info: US3937272 - 1976-02-10
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The US Dept of Energy has a database at: http://www.osti.gov/energycitations/advancedsearch.jsp that has quite a number of full text reports. I changed the "bibliographic info" to "All fields(include full text)" and put in the phrase (with quotes) "combustion efficiency". In the next box I selected "Subject" and put in: foundr*
The first of 2 hits is: INEL--95/0578 Industry-identified combustion research needs: Special study. 1995. This goes into costs and market figures for metal casting industry, starting on page 13 (p.18 of the 124 page .pdf full text). The 2nd one, DOE/ER/12200--T2 Advanced steel reheat furnaces: Research and development. Final report, 1999, is 71 pages and has designs and drawings of furnaces, flow sheets, etc.
Changing that search to: "waste heat" and foundr* gets 10 hits, but the only full text is the INEL--95/0578 just mentioned.
Possibly DOE's "Information Bridge" is better: http://www.osti.gov/bridge/advancedsearch.jsp "waste heat" and foundr* in full text gets 85 hits, many of which look quite unrelated. But trying to limit those words to title or subject gets zero hits — it might be wise to skim through the 4 pages of 85 hits. More promising is the subject: efficien* and foundr*, which gets 6 hits:
102 K DOE/ID13717-1 Final Scientific Report Steel Foundry Refractory Lining Optimization Smith, J.D. ; Peaslee, K.D. 2002 Dec 02
View Full Text Document - PDF Format
3 Mb DOE/ER/12200--T2 Advanced steel reheat furnaces: Research and development. Final report Nguyen, Q. ; Koppang, R. ; Maly, P. ; et.al. 1999 Jan 14
View Full Text Document - PDF Format
8 Mb INEL--95/0578 Industry-identified combustion research needs: Special study Keller, J.G. ; Soelberg, N.R. ; Kessinger, G.F. 1995 Nov 01
View Full Text Document - PDF Format
1 Mb 838776 Determination of Bulk Dimensional Variation in Castings Dr. James F. Cuttino Dr. Edward P. Morse 2005 Apr 14
View Full Text Document - PDF Format
2 Mb 840273 FINAL REPORT: Reduction in Energy Consumption and Variability in Steel Foundry Operations F. Peters 2005 May 24
View Full Text Document - PDF Format
2 Mb 840822 Reduction in Energy Consumption & Variability in Steel Foundry Operations Frank Peters 2005 May 04
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It is certainly well worth looking much more into patents, including the pre-grant published applications at:
http://appft1.uspto.gov/netahtml/PTO/search-adv.html. "waste heat" and foundr$ (note the different truncation: $) gets 17 applications. Since the application database began in 2001, some of the older ones are no doubt granted patents by now. But the application file would be the place to look for the VERY latest inventions. abst/waste and abst/foundr$ (looking for the words in the abstracts — more precise than in the huge full text) gets 5 patent applications. In the Granted Patents database at http://patft.uspto.gov/netahtml/search-adv.htm, the search abst/waste and abst/foundr$ gets 19 hits.
In the Classification manual, at: http://www.uspto.gov/go/classification/ you can look for classes that seem to describe the process you are trying to improve. Class 164 is metal founding, so you can combine that whole class with words, to help get to the specific subclass. For example the search: ccl/164/$ and "heat recovery" looks for every patent since 1976 (you can only search by class and patent number before 1976) in Class 164 (Metal Founding), that has the phrase "heat recovery" anywhere in the title, abstract, or full text. It gets 16 patents.
In ep.espacenet.com, the search for European Class (ECLA): C22B1 ("preliminary treatment of ores and scrap") and title/abstract: "Heat recovery" gets 11 patents — all full text on that site:
1 Method and device for treating bulk products Inventor: MEYER HARTMUT (DE); STAAK THOMAS (DE) Applicant: EC: C22B1/26; F23H11/18; (+2) IPC: F27D15/02 Publication info: US2004115581 - 2004-06-17
2 METHOD FOR EXTRACTION OF VALUABLE MINERALS AND PRECIOUS METALS FROM OIL SANDS ORE BODIES AND OTHER RELATED ORE BODIES Inventor: RENDALL JOHN S (US); VAUGHN VALENTINE W JR (US) Applicant: SOLV EX CORP (US)EC: C22B1/16; C22B3/04; (+2) IPC: C01F7/32; C01G23/053; (+7) Publication info: CA2044731 -1991-12-23
3 METHOD FOR COOLING GASER FROM NON-FERROUS METAL TREATMENT PLANTS, AND THE RELATIVE APPARATUS Inventor: CARMINERY ANTONIO (IT); FELYLO ANDREW (IT) Applicant: SNAMPORGERTY S A (IT)EC: C22B1/02; C22B1/26; (+3) IPC: C22B9/00 Publication info: KR9007973 - 1990-10-23
4 SINTERING EXHAUST-HEAT RECOVERY DEVICE Inventor: TSUKUDA TOSHIO Applicant: SUMITOMO HEAVY INDUSTRIES EC: C22B1/26; F01K3/18C; (+1) IPC: F27B21/08
Publication info: JP63201488 - 1988-08-19
5 Waste gas circulation method and system for sintering apparatus Inventor: FUTAKUCHI TAKASHI; SATO YOSHIMASA; (+3) Applicant: SUMITOMO HEAVY INDUSTRIES (JP)EC: C22B1/20; F27B21/06; (+1) IPC: F27B21/06; F27D17/00; (+1) Publication info: EP0141890 - 1985-05-22
6 Waste gas circulation method and system for sintering apparatus Inventor: FUTAKUCHI TAKASHI (JP); NAKAMURA KIYOFUMI (JP); (+3) Applicant: SUMITOMO METAL IND (JP); SUMITOMO HEAVY INDUSTRIES (JP)EC: C22B1/20B; F27B21/06; (+1) IPC: F27B9/12 Publication info: US4536211 - 1985-08-20
7 HEAT RECOVERY AND MELTING SYSTEM FOR SCRAP METALS Inventor: Applicant: CELOTEX CORP EC: C22B1/00D; C22B7/00B4; (+1) IPC: F27B3/04; F27B3/20 Publication info: GB2086022 - 1982-05-06
8 Agglomeration apparatus Inventor: Applicant: MCKEE & CO ARTHUR G EC: B01J8/10; C22B1/20; (+2) IPC: Publication info: GB1072421 - 1967-06-14
9 Process for roasting by fluidization, more particularly for magnetizing roasting Inventor: Applicant: SIDERURGIE FSE INST RECH EC: C22B1/02; C22B1/10; (+1) IPC: Publication info: GB1008938 - 1965-11-03
10 Heat recovery in fluosolids process Inventor: JUKKOLA WALFRED W Applicant: DORR OLIVER INC EC: C22B1/10; F28C3/16 IPC: Publication info: US2965449 - 1960-12-20
11 Method for burning of materials with heat recovery Inventor: LOUIS PETERSEN Applicant: SMIDTH & CO AS F L EC: B01J8/08H; C22B1/10; (+1)IPC: Publication info: US2757921 - 1956-08-07
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Searching scholar.google.com may be discouraging — LOTS of hits in it link you to full text journals that can ONLY be accessed on university campuses, or by authorized login passwords. A lot of it is high-dollar research journal articles and citations from them. A way around that is to use site:edu in regular Google — for example: foundry "waste heat recovery" site:edu gets 50 hits, some of which may well be full text papers published by university departments and loaded on their sites. The key here is to try many word combinations, and look for the tell-tale .pdf that indicates full text. Site:edu.au or site:ac.uk are other possibilities for getting technical information for free.
Possibly some current books on foundry technology would be helpful, but searching for the few chapters in "green engineering" books can be very tricky. Print.google.com lets you search books, but it costs money to display actual pages. What you can do is get titles, then search large academic or public libraries for those titles. Google Print will give you actual page references. For example, the search: foundry efficiency heat finds 223 pages in @72 books.
Similarly, www.questia.com looks for book chapters and articles in journals, but you have to pay to see full text. foundry "heat recovery" gets 7 hits, foundries "heat recovery" gets 9, and foundries "environmental design" gets 22. You may well need to go to a large public or academic library, if the free web sites don't get all the information you need. Academic Search Premier (a multidisciplinary database with a lot of full text, and general interest to scholarly journal coverage) gets 27 hits for: foundr* and environment* and pollut*. The more popular public library database Masterfile Premier gets 43 hits for that same search — 25 if you limit to full text.
Please let us know how this works out.