Nothing Special   »   [go: up one dir, main page]

CN1119216A - Process for preparing neodymium and neodymium-dysprosium compounds by recovering waste neodymium-iron-boron - Google Patents

Process for preparing neodymium and neodymium-dysprosium compounds by recovering waste neodymium-iron-boron Download PDF

Info

Publication number
CN1119216A
CN1119216A CN94111454A CN94111454A CN1119216A CN 1119216 A CN1119216 A CN 1119216A CN 94111454 A CN94111454 A CN 94111454A CN 94111454 A CN94111454 A CN 94111454A CN 1119216 A CN1119216 A CN 1119216A
Authority
CN
China
Prior art keywords
neodymium
solution
acid
precipitation
obtains
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN94111454A
Other languages
Chinese (zh)
Inventor
李呙昕
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JUNTAI RARE-EARTH INDUSTRY Co Ltd TAIXING CITY
Original Assignee
JUNTAI RARE-EARTH INDUSTRY Co Ltd TAIXING CITY
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by JUNTAI RARE-EARTH INDUSTRY Co Ltd TAIXING CITY filed Critical JUNTAI RARE-EARTH INDUSTRY Co Ltd TAIXING CITY
Priority to CN94111454A priority Critical patent/CN1119216A/en
Publication of CN1119216A publication Critical patent/CN1119216A/en
Pending legal-status Critical Current

Links

Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Recycling

Landscapes

  • Manufacture And Refinement Of Metals (AREA)

Abstract

The process for recovering and preparing Nd or Nd-Dy compounds from waste Nd-Fe-B alloy features that according to the properties of Nd-Fe-B alloy and its member elements, acid dissolving, precipitation, or extraction separation steps are used for removing non-rare-earth impurities step-by-step to obtain rare-earth oxide. The rare-earth product contains over 98% of total rare-earth content and under 0.2% of Fe content, conforming to requirement of making Nd-Fe-B alloy.

Description

Useless neodymium iron boron reclaims the method for producing neodymium and neodymium dysprosium compound
The present invention relates to hydrometallurgy and produce neodymium and neodymium dysprosium compound.
The production of neodymium compound at present is to adopt various rare-earth mineral, and mixed rare-earth oxide and muriate made through pre-treatment (acid is molten), extracting and separating, three steps of aftertreatment (precipitation, calcination).Annual both at home and abroad production of neodymium-iron-boron magnetic material and consumption are very big, the so just unavoidable NdFeB material that gives up in enormous quantities that produces, according to the retrieval, the useless neodymium iron boron of recycling makes neodymium compound and reaches than higher purity, goes back the both economical rational technology of none at present.
The purpose of this invention is to provide and a kind of wherein rare earth element is handled, reclaimed to useless neodymium iron boron, make the processing method of needed single neodymium compound or neodymium dysprosium compound, to remedy the deficiency of the raw material neodymium compound of producing the required rare earth metal of neodymium-iron-boron magnetic material on the market.
Character and composition situation according to neodymium-iron-boron magnetic material self, rare earth element is different with the characteristic of iron boron, the neodymium iron boron that will give up dissolving (hydrochloric acid, sulfuric acid, nitric acid) obtains waste material acid solution (chlorate solution, sulfate liquor, nitrate solution), the present invention adopts following method to handle, to obtain needed rare-earth products:
(1) waste solution adds Sodium sulfate anhydrous.min(99) (Na 2SO 4) carry out double salt precipitation, adding caustic soda (NaOH) alkali after the throw out washing changes, and precipitation of hydroxide adds hydrochloric acid (sulfuric acid, nitric acid), and to carry out acid molten, adds oxalic acid (H 2C 2O 4) or carbon ammonium (NH 4HCO 3) precipitation, the throw out washing filtering at high temperature carries out calcination, the rare earth oxide that obtains reclaiming with throw out then.
(2) the waste material acid solution adds H 2O 2With Fe 2+Be oxidized to Fe 3+, add HN 3H 2O transfers solution PH=3.5~4.5, forms Fe (OH) 3Precipitation, filtration, supernatant liquor carry out oxalic acid precipitation by method (1), make rare earth oxide.
(3) the waste material acid solution adds H 2O 2With Fe 2+Be oxidized to Fe 3+, adopt neutral extraction agent extracting and separating Fe 2+, the earth solution that obtains adds oxalic acid (or carbon ammonium) precipitation, washing filtering, and throw out at high temperature calcination obtains rare earth oxide.
(4) the waste material acid solution directly adds oxalic acid precipitation, adds H with acid solution 2O 2Washing and filtering, throw out is calcination at high temperature, obtains rare earth oxide.
The rare earth acid solution that obtains by method (1) carries out extracting and separating before oxalic acid precipitation separates different rare earth elements contained in the neodymium iron boron waste material and obtains single Neodymium trichloride and Dysprosium trichloride, and then does oxalic acid precipitation by method (1) and make Neodymium trioxide and dysprosium oxide.
The earth solution that obtains by method (3) extracting and separating can further adopt neodymium and the dysprosium that contains in neutrality or the acidic extractant rare-earth separating solution, obtain single Neodymium trichloride and Dysprosium trichloride, add oxalic acid precipitation, washing filtering, throw out calcination at high temperature obtains Neodymium trioxide and dysprosium oxide.
The present invention recycles neodymium iron boron waste material, makes needed rare-earth products, reaches the comprehensive utilization of waste product, and decontamination cuts the waste, and has good economic benefits and social benefit.
Embodiment: waste material (by material: hydrochloric acid<industry 〉=1: 3~5) is added the dissolving with hydrochloric acid groove carry out acid and dissolve, obtain the chloride soln of iron and rare earth, and boron is insoluble to hydrochloric acid, treat all to dissolve after-filtration, filter residue is used to reclaim boron, filtrate is squeezed into setting tank, (by oxalic acid: rare earth content=1.2~1.5: (solution acidity is controlled at [H]=0.01~1N) and stirs and precipitate 1) to add oxalic acid to measure liquor capacity and rare earth concentration, after treating that precipitation is fully also clarified, the siphon supernatant liquor is used to reclaim iron, and throw out is with containing 1~3%H 2O 21~3%Hcl1~3% 2C 2O 4Solution washing 3~5 times, after iron level meets the requirements in the mensuration throw out, filtration obtains rare-earth oxalate, the oxalate earthen bowl of packing into is put into chamber type electric resistance furnace or tunnel furnace, under 850~900 ℃, constant temperature calcination 2-3 hour, cooling is come out of the stove and is obtained oxide compound, plastic bag packaging is as the raw material of electrolytic metal.Whole process flow:
Figure A9411145400071

Claims (5)

1, the neodymium iron boron dissolving (hydrochloric acid, sulfuric acid, nitric acid) of will giving up obtains waste material acid solution (chlorate solution, sulfate liquor, nitrate solution), adopts following method to handle, to obtain needed rare-earth products:
(1) waste solution adds Sodium sulfate anhydrous.min(99) (Na 2SO 4) carry out double salt precipitation, adding caustic soda (NaOH) alkali after the throw out washing changes, and precipitation of hydroxide adds hydrochloric acid (sulfuric acid, nitric acid), and to carry out acid molten, adds oxalic acid (H 2C 2O 4) or carbon ammonium (NH 4HCO 3) precipitation, the throw out washing filtering at high temperature carries out calcination, the rare earth oxide that obtains reclaiming with throw out then.
(2) the waste material acid solution adds H 2O 2With Fe 2+Be oxidized to Fe 3+, add HN 3H 2O transfers solution PH=3.5~4.5, forms Fe (OH) 3Precipitation, filtration, supernatant liquor carry out oxalic acid precipitation by method (1), make rare earth oxide.
(3) the waste material acid solution adds H 2O 2With Fe 2+Be oxidized to Fe 3+, adopt neutral extraction agent extracting and separating Fe 2+, the earth solution that obtains adds oxalic acid (or carbon ammonium) precipitation, washing filtering, and throw out at high temperature calcination obtains rare earth oxide.
(4) the waste material acid solution directly adds oxalic acid precipitation, adds H with acid solution 2O 2Washing and filtering, throw out is calcination at high temperature, obtains rare earth oxide.
2, according to (1) described method in the claim 1, the rare earth acid solution that obtains is carried out extracting and separating before oxalic acid precipitation different rare earth elements separation contained in the neodymium iron boron waste material are obtained single Neodymium trichloride and Dysprosium trichloride, and then do oxalic acid precipitation by method (1) and make Neodymium trioxide and dysprosium oxide.
3, according to (3) described method in the claim 1, the earth solution that extracting and separating is obtained can further adopt neodymium and the dysprosium that contains in neutrality or the acidic extractant rare-earth separating solution, obtain single Neodymium trichloride and Dysprosium trichloride, add oxalic acid precipitation, washing filtering, throw out calcination at high temperature obtains Neodymium trioxide and dysprosium oxide.
4, method according to claim 1, throw out is with containing 1~3%H 2O 2, 1~3%Hcl, 1~3%H 2C 2O 4Solution washing 3~5 times.
5, method according to claim 1 is with the calcination 2~3 hours under 800~900 ℃ high temperature of the throw out behind the washing filtering.
CN94111454A 1994-09-22 1994-09-22 Process for preparing neodymium and neodymium-dysprosium compounds by recovering waste neodymium-iron-boron Pending CN1119216A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN94111454A CN1119216A (en) 1994-09-22 1994-09-22 Process for preparing neodymium and neodymium-dysprosium compounds by recovering waste neodymium-iron-boron

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN94111454A CN1119216A (en) 1994-09-22 1994-09-22 Process for preparing neodymium and neodymium-dysprosium compounds by recovering waste neodymium-iron-boron

Publications (1)

Publication Number Publication Date
CN1119216A true CN1119216A (en) 1996-03-27

Family

ID=5035322

Family Applications (1)

Application Number Title Priority Date Filing Date
CN94111454A Pending CN1119216A (en) 1994-09-22 1994-09-22 Process for preparing neodymium and neodymium-dysprosium compounds by recovering waste neodymium-iron-boron

Country Status (1)

Country Link
CN (1) CN1119216A (en)

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1077603C (en) * 1998-05-12 2002-01-09 住友金属矿山株式会社 Recovering method of valuable composition from rare earth element-containing material and alloy powder obtained therefrom
CN1295357C (en) * 2005-05-08 2007-01-17 西安西骏新材料有限公司 Recovery method of valuable element in neodymium iron boron waste material
CN1321201C (en) * 2004-08-25 2007-06-13 日本磁力选矿株式会社 Method for recovering rear-earth element
CN102583492A (en) * 2012-02-20 2012-07-18 甘肃稀土新材料股份有限公司 Production process of neodymium oxide with small bulk density
WO2012113263A1 (en) * 2011-02-26 2012-08-30 赣州力赛科新技术有限公司 Method for removing iron and aluminum from iron-based waste material containing high-value elements through natural oxidation
CN103093916A (en) * 2013-02-06 2013-05-08 南京信息工程大学 Neodymium iron boron magnetic materials and preparation method of the same
CN103160681A (en) * 2013-02-19 2013-06-19 北京工业大学 Preprocessing method of preparing neodymium iron boron alloy by using neodymium iron boron grinding-material oil sludge
CN103160682A (en) * 2013-02-19 2013-06-19 北京工业大学 Preprocessing method of preparing neodymium iron boron alloy by using neodymium iron boron linear-cutting oil sludge
CN103343233A (en) * 2013-07-19 2013-10-09 北京工业大学 Method for recovering neodymium and iron from neodymium iron boron oil sludge
CN103343235A (en) * 2013-07-19 2013-10-09 北京工业大学 Method for recovering neodymium and iron from neodymium iron boron oil sludge through two-step co-precipitation
CN103343234A (en) * 2013-07-19 2013-10-09 北京工业大学 Method for preparing neodymium and iron oxides by using neodymium iron boron oil sludge through regeneration and co-precipitation
CN103667715A (en) * 2013-12-17 2014-03-26 北京工业大学 Method for recovering Nd (neodymium), Pr (praseodymium), Dy (dysprosium), Co (cobalt) and Fe (iron) simultaneously from NdFeB (neodymium iron boron) oil sludge under C2H2O4-OH system
CN103911516A (en) * 2014-03-27 2014-07-09 全南晶环科技有限责任公司 Process for extracting neodymium from waste electronic ceramic powder
CN103917672A (en) * 2011-11-14 2014-07-09 住友金属矿山株式会社 Method for recovering rare earth element
CN104388711A (en) * 2014-12-11 2015-03-04 内蒙古科技大学 Method for recovering rare earth by leaching rare earth oxide molten slag
WO2016019044A1 (en) * 2014-07-29 2016-02-04 Trustees Of The University Of Pennsylvania Simple chemical method for the separation of rare earth metals
CN107470640A (en) * 2017-09-26 2017-12-15 北京京磁电工科技有限公司 The waste material of neodymium iron boron magnetic body recycles preparation technology
CN107758679A (en) * 2017-10-10 2018-03-06 北京工业大学 A kind of technique that boron is reclaimed from waste and old NdFeB material
CN107794373A (en) * 2017-11-06 2018-03-13 王志勇 The integrated conduct method of the useless magnetic material of neodymium iron boron
CN108004412A (en) * 2017-12-28 2018-05-08 长春工程学院 A kind of room temperature wet method ozone oxidation goes iron removaling and the equipment and technique of organic matter from neodymium iron boron greasy filth waste material
CN108018430A (en) * 2017-12-28 2018-05-11 长春工程学院 A kind of device and method of neodymium iron boron powdered scrap room temperature wet oxidation iron removaling
CN108018429A (en) * 2017-12-28 2018-05-11 长春工程学院 A kind of method that room temperature ultrasound-hydrogen peroxide wet oxidation removes the impurity such as iron removaling and organic matter from neodymium iron boron waste material
CN108018427A (en) * 2017-12-28 2018-05-11 长春工程学院 A kind of method of room temperature wet method UV-ozone oxidation organics removal from neodymium iron boron greasy filth waste material
CN108193051A (en) * 2017-12-28 2018-06-22 长春工程学院 A kind of neodymium iron boron powdered scrap room temperature wet method air, ozone secondary oxidation remove the device and method of iron
CN108559845A (en) * 2017-12-28 2018-09-21 长春工程学院 A kind of method that the oxidation of room temperature wet method ultrasound-ozone removes iron and organic matter from neodymium iron boron greasy filth waste material
CN110607537A (en) * 2019-09-26 2019-12-24 江西理工大学 Method for synchronously and efficiently extracting rare earth and iron from high-value recycled neodymium iron boron waste
CN112301220A (en) * 2020-10-30 2021-02-02 包头市聚峰稀土有限责任公司 Method for reducing iron content in rare earth sulfate water leaching solution

Cited By (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1077603C (en) * 1998-05-12 2002-01-09 住友金属矿山株式会社 Recovering method of valuable composition from rare earth element-containing material and alloy powder obtained therefrom
CN1321201C (en) * 2004-08-25 2007-06-13 日本磁力选矿株式会社 Method for recovering rear-earth element
CN1295357C (en) * 2005-05-08 2007-01-17 西安西骏新材料有限公司 Recovery method of valuable element in neodymium iron boron waste material
WO2012113263A1 (en) * 2011-02-26 2012-08-30 赣州力赛科新技术有限公司 Method for removing iron and aluminum from iron-based waste material containing high-value elements through natural oxidation
CN103917672A (en) * 2011-11-14 2014-07-09 住友金属矿山株式会社 Method for recovering rare earth element
CN103917672B (en) * 2011-11-14 2016-06-22 住友金属矿山株式会社 The recovery method of rare earth element
CN102583492A (en) * 2012-02-20 2012-07-18 甘肃稀土新材料股份有限公司 Production process of neodymium oxide with small bulk density
CN103093916A (en) * 2013-02-06 2013-05-08 南京信息工程大学 Neodymium iron boron magnetic materials and preparation method of the same
CN103160681A (en) * 2013-02-19 2013-06-19 北京工业大学 Preprocessing method of preparing neodymium iron boron alloy by using neodymium iron boron grinding-material oil sludge
CN103160682A (en) * 2013-02-19 2013-06-19 北京工业大学 Preprocessing method of preparing neodymium iron boron alloy by using neodymium iron boron linear-cutting oil sludge
CN103343233A (en) * 2013-07-19 2013-10-09 北京工业大学 Method for recovering neodymium and iron from neodymium iron boron oil sludge
CN103343234A (en) * 2013-07-19 2013-10-09 北京工业大学 Method for preparing neodymium and iron oxides by using neodymium iron boron oil sludge through regeneration and co-precipitation
CN103343235A (en) * 2013-07-19 2013-10-09 北京工业大学 Method for recovering neodymium and iron from neodymium iron boron oil sludge through two-step co-precipitation
CN103343235B (en) * 2013-07-19 2015-03-25 北京工业大学 Method for recovering neodymium and iron from neodymium iron boron oil sludge through two-step co-precipitation
CN103343233B (en) * 2013-07-19 2015-10-28 北京工业大学 A kind of neodymium iron boron greasy filth reclaims the method for neodymium iron
CN103667715A (en) * 2013-12-17 2014-03-26 北京工业大学 Method for recovering Nd (neodymium), Pr (praseodymium), Dy (dysprosium), Co (cobalt) and Fe (iron) simultaneously from NdFeB (neodymium iron boron) oil sludge under C2H2O4-OH system
CN103667715B (en) * 2013-12-17 2016-05-18 北京工业大学 A kind of at C2H2O4Under-OH system, from neodymium iron boron greasy filth, reclaim the method for neodymium, praseodymium, dysprosium, cobalt, iron simultaneously
CN103911516A (en) * 2014-03-27 2014-07-09 全南晶环科技有限责任公司 Process for extracting neodymium from waste electronic ceramic powder
CN103911516B (en) * 2014-03-27 2015-10-28 全南晶环科技有限责任公司 A kind of technique extracting neodymium from waste electronic ceramics powder
WO2016019044A1 (en) * 2014-07-29 2016-02-04 Trustees Of The University Of Pennsylvania Simple chemical method for the separation of rare earth metals
US10704122B2 (en) 2014-07-29 2020-07-07 The Trustees Of The University Of Pennsylvania Simple chemical method for the separation of rare earth metals
CN104388711A (en) * 2014-12-11 2015-03-04 内蒙古科技大学 Method for recovering rare earth by leaching rare earth oxide molten slag
CN107470640A (en) * 2017-09-26 2017-12-15 北京京磁电工科技有限公司 The waste material of neodymium iron boron magnetic body recycles preparation technology
CN107470640B (en) * 2017-09-26 2019-10-01 北京京磁电工科技有限公司 The waste material of neodymium iron boron magnetic body recycles preparation process
CN107758679A (en) * 2017-10-10 2018-03-06 北京工业大学 A kind of technique that boron is reclaimed from waste and old NdFeB material
CN107758679B (en) * 2017-10-10 2020-01-24 北京工业大学 Process for recovering boron from waste neodymium iron boron material
CN107794373A (en) * 2017-11-06 2018-03-13 王志勇 The integrated conduct method of the useless magnetic material of neodymium iron boron
CN107794373B (en) * 2017-11-06 2019-01-22 孙东江 The integrated conduct method of the useless magnetic material of neodymium iron boron
CN108193051A (en) * 2017-12-28 2018-06-22 长春工程学院 A kind of neodymium iron boron powdered scrap room temperature wet method air, ozone secondary oxidation remove the device and method of iron
CN108559845A (en) * 2017-12-28 2018-09-21 长春工程学院 A kind of method that the oxidation of room temperature wet method ultrasound-ozone removes iron and organic matter from neodymium iron boron greasy filth waste material
CN108018427A (en) * 2017-12-28 2018-05-11 长春工程学院 A kind of method of room temperature wet method UV-ozone oxidation organics removal from neodymium iron boron greasy filth waste material
CN108018429A (en) * 2017-12-28 2018-05-11 长春工程学院 A kind of method that room temperature ultrasound-hydrogen peroxide wet oxidation removes the impurity such as iron removaling and organic matter from neodymium iron boron waste material
CN108018430A (en) * 2017-12-28 2018-05-11 长春工程学院 A kind of device and method of neodymium iron boron powdered scrap room temperature wet oxidation iron removaling
CN108004412A (en) * 2017-12-28 2018-05-08 长春工程学院 A kind of room temperature wet method ozone oxidation goes iron removaling and the equipment and technique of organic matter from neodymium iron boron greasy filth waste material
CN110607537A (en) * 2019-09-26 2019-12-24 江西理工大学 Method for synchronously and efficiently extracting rare earth and iron from high-value recycled neodymium iron boron waste
CN110607537B (en) * 2019-09-26 2021-02-26 江西理工大学 Method for synchronously and efficiently extracting rare earth and iron from high-value recycled neodymium iron boron waste
CN112301220A (en) * 2020-10-30 2021-02-02 包头市聚峰稀土有限责任公司 Method for reducing iron content in rare earth sulfate water leaching solution

Similar Documents

Publication Publication Date Title
CN1119216A (en) Process for preparing neodymium and neodymium-dysprosium compounds by recovering waste neodymium-iron-boron
CN103374652B (en) Method for comprehensively recycling rare earth and fluorine in process of treating bastnaesite
CN102443701B (en) Clean metallurgic comprehensive utilization method of iron vitriol slags
CN102190325B (en) Method for recovering rare earth from ionic type rare earth crude ore
CN102206755B (en) Method for separating and recovering valuable elements from neodymium-iron-boron wastes
CN1255560C (en) Process for recovering rare earth from neodymium-ion-boron waste materials
CN104775026B (en) A kind of method that high-purity uranium, thorium and mischmetal are extracted from excellent molten slag
US5362459A (en) Neodymium recovery process
CN102277483B (en) Method for preparing rare earth chloride by using Baiyunebo rare earth concentrate
CN103695671B (en) Reclaim in a kind of spent acid by producing zirconates, the method for purification Scium trioxide powder
CN110358923B (en) Method for extracting indium and recycling zinc oxide smoke dust by using zinc oxide smoke dust
CN101532094A (en) Technology for full-process extracting and separating nickel and cobalt from acid material system with high content of calcium and magnesium impurities
CN102011020A (en) Method for recovering rare earth elements from neodymium-iron-boron wastes
CN105256143B (en) Scandium and the method for other rare earths are extracted from zirconium oxychloride acid pickle
CN103290224A (en) Recovery process for valuable metals in tungsten residues
CN101376929A (en) Method for extracting bismuth from bismuth ore concentrate or material containing bismuth
CN102965506B (en) Method for removing aluminum from rare earth solution by benzoate precipitation method
CN103667749A (en) Method for enriching scandium in anatase raw ore
CN109593977A (en) A method of removal is containing iron ion in neodymium, praseodymium, dysprosium and ferrous solution
CN103614563A (en) Comprehensive recovery and processing method for red mud waste residues and titanium dioxide spent liquor
CN109574181A (en) A kind of method that rare earth oxalate precipitate waste water reclaiming is administered
CN103572064A (en) Method for enriching lead and recovering rare earth from rare earth lead slag
CN111485110A (en) Method for improving utilization rate of valuable elements in rare earth
CN103215451A (en) Recovery method of rare earth elements in ionic rare earth smelting acid dissolution slag
US3699208A (en) Extraction of beryllium from ores

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C01 Deemed withdrawal of patent application (patent law 1993)
WD01 Invention patent application deemed withdrawn after publication