Liquid purification or separation – Processes – Liquid/liquid solvent or colloidal extraction or diffusing...
Reexamination Certificate
1999-08-30
2002-01-15
Fortuna, Ana (Department: 1723)
Liquid purification or separation
Processes
Liquid/liquid solvent or colloidal extraction or diffusing...
C210S639000, C210S651000, C210S739000, C210S257200, C134S010000
Reexamination Certificate
active
06338803
ABSTRACT:
STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
CROSS REFERENCE TO RELATED APPLICATIONS
Not applicable.
BACKGROUND OF THE INVENTION
The process of the present invention relates to treating waste water by reverse osmosis. More specifically, this process involves treating waste water that contains hydrofluoric acid (HF) and mixed acid etchant (MAE) waste.
Currently, waste water containing HF and MAE waste is generated by silicon wafer manufacturers. MAE waste contains mixtures of acids including hydrofluoric acid and nitric acid (NHO
3
). It also may contain acetic acid (CH
3
CO
2
H). Still further, the MAE waste contains dissolved silica (SiO
2
). Dissolved silica may also be found in the HF stream that is part of the waste water. Conventionally, this waste water is treated with calcium hydroxide (Ca(OH)
2
, which is lime) or calcium chloride (CaCl
2
) to precipitate fluoride. The disadvantage with this process is that it is difficult to produce clean and reusable water, and instead, much of the waste water must be disposed. Another disadvantage with this process is that when CaCl
2
is used, it is especially difficult to reclaim the water due to the presence of a high concentration of chloride. Another disadvantage is that lime or calcium chloride treatment does not remove nitrates. Another method for treating this waste is by biological denitrification so as to remove nitrates from the waste water. However, such a process requires expensive capital costs. Still further, both of these conventional processes are not able to concentrate the waste being removed, and therefore, these processes require large vessels for processing the waste water.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a process for treating waste water containing hydrofluoric acid, mixed acid etchant waste, and dissolved silica that is able to produce clean, reusable water.
Another object of the present invention is to provide a waste water treatment system that results in lower capital costs compared to conventional systems because the waste is concentrated thus requiring smaller treatment vessels.
According to the present invention, the foregoing and other objects are achieved by a process for treating waste water containing hydrofluoric acid, mixed acid etchant waste, dissolved silica, and solid particles and a system for performing this process. This process involves adjusting the pH of the waste water to about 7 or above, filtering the waste water to remove solid particles, adding an anti-scalant to the waste water, and feeding the waste water through a reverse osmosis membrane. The reverse osmosis membrane separates the waste water into a permeate stream, which product, and a reject stream.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
REFERENCES:
patent: 1324118 (1919-12-01), Hottinger et al.
patent: 3075645 (1963-01-01), Riddick
patent: 3097163 (1963-07-01), Riddick
patent: 3101317 (1963-08-01), Starry
patent: 3521752 (1970-07-01), Lindman
patent: 3544476 (1970-12-01), Aiba et al.
patent: 4016075 (1977-04-01), Wilkins
patent: 4165264 (1979-08-01), Satchell, Jr.
patent: 4188291 (1980-02-01), Anderson
patent: 4207183 (1980-06-01), Herrigel
patent: 4246102 (1981-01-01), Hjelmener et al.
patent: 4260493 (1981-04-01), Kretas et al.
patent: 4276180 (1981-06-01), Matson
patent: 4420401 (1983-12-01), Kretas et al.
patent: 4450057 (1984-05-01), Kelly
patent: 4504356 (1985-03-01), Mulder et al.
patent: 4731187 (1988-03-01), Moriya et al.
patent: 4765913 (1988-08-01), Featherstone
patent: 4778532 (1988-10-01), Mcconnell et al.
patent: 4780211 (1988-10-01), Lien
patent: 4915844 (1990-04-01), Imamura et al.
patent: 4917123 (1990-04-01), McConnell et al.
patent: 4938876 (1990-07-01), Ohsol
patent: 4957634 (1990-09-01), Bowers, Jr.
patent: 4990260 (1991-02-01), Pisani
patent: 5078900 (1992-01-01), Wegner
patent: 5108620 (1992-04-01), Wester et al.
patent: 5164095 (1992-11-01), Sparapany et al.
patent: 5171453 (1992-12-01), Communal
patent: 5182023 (1993-01-01), O'Connor et al.
patent: 5205939 (1993-04-01), Syrinek
patent: 5246686 (1993-09-01), Cuer et al.
patent: 5362461 (1994-11-01), Ohmi et al.
patent: 5382423 (1995-01-01), Ohmi et al.
patent: 5453206 (1995-09-01), Browne
patent: 5510040 (1996-04-01), Miller et al.
patent: 5512181 (1996-04-01), Matchett
patent: 5556545 (1996-09-01), Volchek et al.
patent: 5575915 (1996-11-01), Nakamura et al.
patent: 5605633 (1997-02-01), Nakamura et al.
patent: 5609765 (1997-03-01), Bowman
patent: 5620629 (1997-04-01), Salmen et al.
patent: 5871648 (1999-02-01), Allen et al.
patent: 5876685 (1999-03-01), Krulik et al.
patent: 5965027 (1999-10-01), Allen et al.
patent: 6050283 (2000-04-01), Hoffman et al.
patent: 6106722 (2000-08-01), Chew et al.
patent: 6158445 (2000-12-01), Olesen et al.
patent: WO 97/47380 (1997-12-01), None
Aspila, K., et al., “Studies on the Stability of Dithiocarbamic Acids,” Chemistry Department, Carleton University, Ontairo, Canada,Talanta, 1969, vol. 16, pp. 1099 to 1102.
Harris, G. B., et al., “The Stability of Arsenic-Bearing Residues,” Paper presented at TMS-AIME Symposium, “Arsenic Metallurgy-Fundamentals and Application,” Phoenix, Arizona Jan. 25-29, 1988.
Hulanicki, A., et al., “Complexation Reactions of Dithiocarbamates,” Department of Inorganic Chemistry, University of Warsaw, Poland,Talanta Review, 1967, vol. 14, pp. 1371 to 1392.
Janssen, M. J., “The Stability Constants of Metal Complexes of Some N-Dialkyldithiocarbamic Acids,” Institute for Organic Chemistry T.N.O, Utrecht, the Netherlands), 75 (1956)RECUEIL1411.
Janssen, M. J., “The Stability Constants of Metal Complexes of Some N-Dialkyldithiocarbamic Acids,” Institute for Organic Chemistry T.N.O, Utrecht, the Netherlands), 76 (1957)RECUEIL827.
Joris, Serge J., et al. “On the Monobasic or Dibasic Character of Dithiocarbamic Acids,” Department of Chemistry, Carleton University, Ottawa I, Ontario,Analytical Chemistry, vol. 41, No. 11, Sep. 1969.
Miertu{haeck over (s)}, Stanislav, et al., “Theoretical Study of the Electron Structure and Properties of Dithiocabamates and Their Complexes With Transition Metals,” Department of Analytical Chemistry, Slovak Technical University, 812.37 andbCancer Research Institute, Slovak Academy of Science, 812.32 Bratislava,Collection Czechoslovak Chem. Commun. [vol. 49] 1984.
Scharfe, R. R., et al., “Stability of Metal Dithiocarbamate Complexes,” Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6, Canada.
Tetsumi, T., et al., “Direct Reaction of Metal Powders With Several Sodium Dithiocarbamates,” Department of Pharmaceutical Sciences, Setsunan University, Nagao Toge-cho, Hirakata-shi, Osaka 5730-01, Japan.
Wasay, S.A., et al., “Removal of Trace Heavy Metals by Metal Chelates,”Intern J. Environmental Studies, 1990, vol. 36, pp. 191-197.
Cattaneo, Jeffrey F., “Removal Of Copper Ions From Rinse Water Using TiO2Photocatalysis”,SSA Journal, vol. 13—Spring 1999, pp. 55-59.
Duyvesteyn, W.P.C. et al., “Ammonia Leaching Process for Escondida Copper Concentrates,” pp. C125-C140, reprinted byExtractive metallurgy of Copper, Nickel and Cobalt, vol. I:Fundamental Aspects, edited by Reddy R.G. and Weizenbach R.N. (Warrendale, PA: The Minerals, Metals and Materials Society, Inc. (TMS), 1993).
Egermeier, John, et al., “Treatment of Wastewater Generated by Copper Metalization and CMP,” Proceedings of Watertech '99 Executive Form, Oct. 5-6, 1999, Portland, Oregon.
Maeda, Bruce T. et al., “Treating Wastes Generated by Copper Electroplating Tools”,MICRO, Sep. 1999, pp. 39-49.
Mendicino, Laura, et al., “The Environment, Health and Safety Side of Copper Metalization,”Semiconductor Inter
Campbell Deon Eugene
Francis Jereme
James Dustin Kimbel
Stocker Thomas
Fortuna Ana
Koch Microelectronic Service Co., Inc.
Shook Hardy & Bacon LLP
LandOfFree
Process for treating waste water containing hydrofluoric... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for treating waste water containing hydrofluoric..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for treating waste water containing hydrofluoric... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2830935