[go: up one dir, main page]

US20200032369A1 - Method of operating a pelletizing plant - Google Patents

Method of operating a pelletizing plant Download PDF

Info

Publication number
US20200032369A1
US20200032369A1 US16/484,367 US201816484367A US2020032369A1 US 20200032369 A1 US20200032369 A1 US 20200032369A1 US 201816484367 A US201816484367 A US 201816484367A US 2020032369 A1 US2020032369 A1 US 2020032369A1
Authority
US
United States
Prior art keywords
products
agglomerates
pellets
green pellets
furnace
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.)
Abandoned
Application number
US16/484,367
Other languages
English (en)
Inventor
Georg Strüber
Gilles Nouaille-Degorce
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.)
Paul Wurth SA
Original Assignee
Paul Wurth SA
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 Paul Wurth SA filed Critical Paul Wurth SA
Assigned to PAUL WURTH S.A. reassignment PAUL WURTH S.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: STRÜBER, Georg, NOUAILLE-DEGORCE, Gilles
Publication of US20200032369A1 publication Critical patent/US20200032369A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/2406—Binding; Briquetting ; Granulating pelletizing
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/2413—Binding; Briquetting ; Granulating enduration of pellets
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/242—Binding; Briquetting ; Granulating with binders
    • C22B1/243—Binding; Briquetting ; Granulating with binders inorganic

Definitions

  • the present disclosure generally relates to the field of iron making. More particularly, it relates to the agglomeration of iron ore by pelletization and specifically to a method of operating a pelletizing plant.
  • the blast furnace is a countercurrent gas-solid reactor in which the solid charge materials move downward while the hot reducing gases flow upward.
  • the best possible contact between the solids and the reducing gas is obtained with a permeable burden, which permits not only a high rate of gas flow but also a uniform gas flow, with a minimum of channeling of the gas.
  • agglomeration processes have been developed in order to enable the use of fine material, improve the burden permeability and thereby reduce blast furnace coke rates and increase the rate of reduction. They also permit reducing of the amount of fine material blown out of the blast furnace into the gas recovery system. Furthermore, in ironmaking furnaces, agglomerated materials, when they have the proper chemical composition, can substitute for lump ores used as charge ores.
  • Sintering and pelletizing processes are today the two major agglomeration processes, especially for the blast furnace.
  • Sintered ore is made by partially melting and sintering coarse iron ore 0.5 to 3 mm in size into products having a size of 5 to 50 mm.
  • the sintering process uses the combustion heat of coke breeze (fuel).
  • Pellets are made from iron ore that is finer than that used for sintered ore.
  • the fine-grained ore can be relatively easily formed into spheroids, called green balls, typically with a diameter ranging from 9 to 18 mm.
  • the green balls are fired into hard product pellets, so-called indurated pellets or simply pellets.
  • pellets have attracted great interest since they are well adapted for use as raw materials for blast furnaces, but also for direct reduction furnaces.
  • U.S. Pat. No. 3,864,119 discloses a method and apparatus for simultaneously producing heat hardened pellets of two size ranges from finely divided mineral ore.
  • Smaller size green pellets are produced in a balling drum and sent to an induration unit comprising a grate and a rotary kiln.
  • a series of decks collect hardened balls with a predetermined size after the rotary kiln and these are sent to a feedback loop.
  • the feedback loop comprises a balling pan to form larger balls.
  • the larger balls are then placed upon the bed of the smaller size green pellets and fed into the induration unit.
  • both the smaller and larger balls are made from iron ore.
  • U.S. Pat. No. 3,333,951 discloses a process for producing metallized iron ore pellets.
  • the method comprises the steps of blending with the iron ore a solid carbonaceous material and moisture, forming pellets of the moist blend, indurating the pellets, coating the indurated pellets with moistened ore blend, and re-indurating the pellets.
  • pellets from a predetermined size are collected after the indurating process and passed through an agglomeration process with iron ore, before charging them together with green pellets into the indurating apparatus.
  • US 2015/128766 discloses a pelletizing process having two distinct serial stages for producing green pellets from iron ore.
  • the document particularly discloses a feeding installation for an indurating installation having two pelletizing discs.
  • the pelletizing process is desirable for agglomeration of finely divided iron ore concentrates because they are normally of such fine size that they will form into a green ball with little difficulty. Concentrates and high grade ores that are not suitable in size for pelletizing are in some cases ground to the required size.
  • the disclosure provides an improved concept of pelletizing plant, which can more flexibly handle iron ores and by-products produced either by an integrated plant, or a direct reduction unit of a pellet plant.
  • the disclosure proposes a method of operating a pelletizing plant with traditional ore feed and some by-products.
  • the pelletizing plant comprises an indurating furnace in which green pellets are charged and fired to produce hard pellets.
  • the method comprises the steps of preparing iron ore based green pellets; and charging and firing the green pellets in the indurating furnace.
  • the pellets are prepared by conventional pelletizing equipment, e.g. a balling drum and/or a disc pelletizer, so that the pellets are formed by rolling the raw material into a ball.
  • by-products previously agglomerated are charged and fired with the green pellets in the indurating furnace, whereby hardened pellets and hardened agglomerates of by-products are produced in the indurating furnace.
  • a remarkable aspect of the present disclosure is thus the processing of agglomerates of by-products in the indurating furnace, together with green pellets.
  • agglomerates of by-products and green pellets undergo concurrently/simultaneously the same thermal treatment for their hardening in the indurating furnace.
  • by-products is herein used to generally designate the ironmaking, the steelmaking, the pelletization and the direct reduction waste materials, and may typically include one or more of: steelmaking slag, mill scale, scrap fines, oxide fines, dust and sludges collected in offgas lines, fines fractions from the screening units, sludges iron- or flux-bearing blast furnace by-products.
  • These by-products also known as ‘reverts’, may typically have a size in the range of 0.045 to 5 mm.
  • the by-products are preferably agglomerated by a compacting process via pressurized rollers, as is known in the art, to form the agglomerates of by-products.
  • the by-products may be processed in an extrusion or roll device, optionally together with an additive (e.g. lime, binder, etc.), to form lumpy products of predetermined shape and size.
  • a so-called briquetting machine can be used for the preparation of briquette-like agglomerates having a non-spherical shape with dimensions greater than pellets.
  • the briquettes/agglomerates of by-products have a minimum size of 20 mm (in all dimensions).
  • the briquettes may be 20 ⁇ 30 ⁇ 30, or 20 ⁇ 20 ⁇ 40, all expressed in mm, or even larger, e.g. 50 ⁇ 40 ⁇ 100.
  • the agglomerates are formed as lumpy products, typically non-spherical. They typically have a low sphericity, forming rather oblong products, including cushion- and parallellepiped-like shapes, rectangular and oval shapes, and combinations thereof. In some embodiments, the lumpy products could have a rounded shape however with low sphericity.
  • the agglomerates of by-products preferably have larger dimensions than the pellets and are placed in the indurating furnace on top of the pellets to allow for a greater firing duration.
  • the briquetting-type agglomerating process is used to produce agglomerates of by-products that are charged together with the green pellets in the indurating furnace. This is to be put in contrast with conventional plants, where briquettes are not thermally hardened and directly charged into the blast furnace or the electric furnace.
  • a great advantage of the present disclosure is to provide a pelletizing process and plant that is adapted to completely substitute a sinter plant in a coal-based iron making installation. Another great benefit is for gas-based iron making plants, where the present process provides a circular technology. Indeed, as sinter plants are more and more being challenged with higher amounts of finer iron ore, the present disclosure offers an attractive alternative process route for customers operating blast furnaces.
  • the disclosure may be of particular interest for gas-based iron making plants operating with iron ore pellets, where the present process makes it possible to produce pellets and treat all by-products with one technology—whereas current gas-based iron making plants transfer such iron waste into other facilities, outside the plant boundaries.
  • the present disclosure thus constitutes an attractive solution addressing also environmental aspects and namely waste management strategy in a circular technology.
  • the pellets are conventionally prepared in a balling section of the plant, using balling equipment that produces spheroidal or ball-like aggregates referred to as green pellets or green balls. Any appropriate equipment may be used, in particular a balling drum or a disc pelletizer.
  • Pellets are prepared from a fined grained mixture that includes mainly iron bearing material, in particular iron ore, and some additive(s), in particular a binder (e.g. bentonite).
  • the material ready for balling has a grain size below 0.15 mm with about 80% thereof below 45 ⁇ m (i.e. minus 325 mesh).
  • the green pellets typically preferably contain at least 61% iron ore, and have a diameter in the range of 9 to 18 mm, preferably 9-14 mm, typically with a mean diameter of about 12 mm.
  • the indurating furnace can be based on any appropriate technology, e.g. traveling grate furnace, grate-kiln-cooler, or circular induration furnace.
  • the agglomerates of by-products and green pellets are loaded on the charge conveyor of the indurating furnace in two superposed layers, the upper layer mainly comprising the agglomerates of by-products and the lower layer mainly comprising the green pellets.
  • the charging is advantageously made by means of a segregating unit receiving the green pellets and agglomerates of by-products and distributing the latter into the upper and lower layers, based on particle size.
  • the heat treatment in said indurating furnace may be carried out in an oxidizing atmosphere, whereby the obtained hardened pellets and hardened, lumpy agglomerates of by-products have a metallization below 50%, preferably below 10%, more preferably below 5%.
  • the agglomerates of by-products may contain coarse-grained iron ore that cannot typically be processed by pelletizing, however no more than 50 wt. %, preferably no more than 20 wt. %.
  • the disclosure concerns a pelletizing plant comprising:
  • a feeding arrangement configured to charge said green pellets onto a charge conveyor of said indurating furnace
  • the present method may be implemented with agglomerates consisting mainly (above 50 wt. %) of coarse iron ore instead of by-products, or with lower amounts of by-products (less than wt. 50%, namely less than 30 wt. %).
  • FIG. 1 is a process flow diagram of a pelletizing plant according to an embodiment of the disclosure.
  • pelletizing plants for the iron making industry involve generally the following processes:
  • pelletizing plant according to the present disclosure also relies on these three processes, which are briefly described below.
  • the iron ore is ground into fines having qualities required for the subsequent balling process.
  • the pretreatment may typically include concentrating, dewatering, grinding, drying and prewetting.
  • low-grade iron ore is ground into fines to upgrade the quality of the iron ore, remove gangues containing sulfur and phosphorus, and control the size of the grains.
  • the balling equipment may comprise a balling drum or a disc pelletizer, which are the most widely used for forming green balls.
  • the green pellets are charged into a furnace, in which they are fired, to increase their hardness.
  • the following furnace systems may be used for indurating pellets: a traveling grate (straight grate) system and a grate-kiln-cooler system.
  • the traveling grate system consists of a single unit which moves a static layer of pellets.
  • the system has a simple structure for drying, preheating, firing and cooling pellets. Due to its relative ease of operation, along with ease of scaling-up, makes the system one used by many plants.
  • the grate-kiln-cooler system consists mainly of a grate, a kiln and a cooler, respectively designed for drying/preheating, firing, and cooling the pellets. This system allows controlling individually the residence time in each zone of the furnace.
  • FIG. 1 shows a diagram according to one embodiment of the present pelletizing plant 10 .
  • the material pre-processing section may use the above-described conventional material for grinding and handling bulk materials, or any other appropriate equipment.
  • Reference sign 12 designates an indurating furnace, which comprises conveyor means 14 for transferring the material throughout the furnace 10 .
  • the indurating furnace 12 is preferably of the traveling grate type.
  • the furnace 12 comprises zones for drying, preheating, firing and cooling (not shown). The four zones are arranged one after another. Each zone is held at a predetermined temperature, and heat exchange occurs via hot air and/or combustion gas to fire the pellets.
  • the charge conveyor comprises an endless grate car consisting of grate bars with side walls, in which pellets are charged (typically over a layer of already fired material). The green pellets on the grate travel through the zones for drying, preheating, firing and cooling.
  • the hardened pellets and hardened agglomerates of by-products are discharged together, and may be screened to separate them by particle size.
  • the conventional balling section 16 comprises storage bins 18 containing fine grained material ready for balling into associated balling equipment 20 .
  • the storage bins are located downstream of a set of raw materials storage bins 17 a and mixer equipment 17 b of the pre-processing section.
  • a desired recipe of raw materials is prepared on a conveyor belt 17 c and conveyed to the mixer equipment 17 b.
  • the mixture is then forwarded to the respective bins 18 .
  • the balling equipment 20 may be a balling drum or a disc pelletizer. In the balling equipment the raw material is rolled into balls, called green balls. As is known, under the rolling movement of the drum/disc, the raw materials agglomerate to form a ball.
  • Green balls formed in the balling equipment 20 are discharged on a main collecting conveyor 22 , typically a belt conveyor, to carry the on-size green pellets towards the furnace 12 .
  • the transfer of the green pellets onto the conveyor 22 is done by a roller screen 24 .
  • the rolls of the roller screen 24 are configured such that green pellets with desired size proceed to the main collecting conveyor 22 , whereas undersized and oversized pellets as well as fines are separated and collected to be recycled back to the bins 18 .
  • the recycling route is indicated 26 .
  • the collected material is recycled back to the bins 18 or can also be conveyed to a mixing system to properly homogenize all raw materials as appropriate for balling.
  • the storage bins 18 contain a mixture of ready to mix materials, which depends on the desired composition for the green pellets.
  • the mixture comprises at least one type of fine grained iron ore, typically with a mesh minus 320 , and at least one additive, e.g. bentonite or limestone.
  • Annexed Tables 1 and 2 list possible materials for the preparation of green pellets and their properties.
  • the present pelletizing plant 10 further comprises an agglomerating section 40 , for forming agglomerates of reverts-products.
  • the agglomerates formed in this section are also transferred towards the indurating furnace 12 .
  • the agglomerates of by-products are discharged on the main collecting conveyor belt 22 , with the green pellets.
  • the agglomerating section 40 comprises a storage bin 42 with the by-products to be agglomerated.
  • the by-products may be stored in bins 41 a upstream of the storage bin 42 .
  • One or more types of by-products are discharged on a conveyor belt and forwarded to the storage bin 42 , optionally via a mixing/grinding equipment 41 c. These materials are then compacted, typically via a pressurized rollers device 44 , to form lumpy products of predetermined size.
  • the formed aggregates are discharged from device 44 in a screen 46 , where undersized material is recycled to the storage bin 42 , as indicated by return line 47 , while the qualified agglomerates are transferred onto the main collecting conveyor 22 .
  • Table 3 in annex, gives an exemplary list of by-products that can be used for preparing agglomerates in the context of the present process, together with typical grain sizes.
  • the green pellets and agglomerates of by-products are preferably charged into the furnace 12 in two superposed layers.
  • the lower layer 50 on the traveling grate 14 comprises mainly the green pellets.
  • the top layer 52 is mainly formed by the agglomerates of by-products.
  • the furnace feeding unit 54 comprises a double deck roller screen device comprising superposed set of rolls configured to carry the agglomerates toward the furnace.
  • the top roll arrangement 54 1 is configured to transfer the agglomerates of by-products to the furnace
  • the lower roll arrangement 54 2 is configured to carry the green pellets to the furnace.
  • the spacing between the top rolls 54 1 is defined so that green pellets fall through the rolls onto the lower rolls 54 2 .
  • the roll spacing of the lower screen 54 2 is such that green pellets with a given minimum size are carried to the furnace, while undersized green pellets, particles and fines fall through the lower screen 54 2 and are collected.
  • the ends of the respective screens 54 1 and 54 2 are positioned so that the green pellets are deposited first on the furnace conveyor 14 , forming the first layer 50 , and the agglomerates are deposited by the second screen over the first layer 50 , to form the second layer 52 .
  • the ratio between green pellets and agglomerates of by-products, in particular the thickness of each layer 50 , 52 , can be varied by adjusting the amounts of pellets and briquettes delivered onto the main collecting conveyor 22 .
  • the undersized green pellets, particles and fines collected at the lower screen 54 2 are returned to storage bin 42 via a return route 56 , to be recycled into briquettes. It should be noticed that when the agglomerating section 40 is in operation, all undersized material from the furnace feeding system 54 , is preferably conveyed to the storage bin 42 .
  • the pellets, particles and fines collected at the lower screen 54 2 may be recycled towards the pelletizing section 16 , as indicated by return route 58 (dashed line). This is return route is namely used when the agglomerating section 40 is not in operation.
  • the presently described process and plant can be operated with agglomerates consisting mainly of coarse iron ore, i.e. having a grain size over 0.150 mm, typically in the range of 0.150 to 5.0 mm.
  • agglomerates are likewise prepared in agglomerating section.
  • the coarse-grained iron ore content is above 50 wt. % and can go up to 80 wt. % and more. They may also contain a fraction of reverts, i.e. less than 50 wt. % and e.g. less than 20 wt. %.
  • the same protocols and additives can be used as described above with reference to reverts.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US16/484,367 2017-02-10 2018-02-08 Method of operating a pelletizing plant Abandoned US20200032369A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
LU100075A LU100075B1 (en) 2017-02-10 2017-02-10 Method of Operating a Pelletizing Plant
LU100075 2017-02-10
PCT/EP2018/053140 WO2018146183A1 (fr) 2017-02-10 2018-02-08 Procédé d'exploitation d'une installation de bouletage

Publications (1)

Publication Number Publication Date
US20200032369A1 true US20200032369A1 (en) 2020-01-30

Family

ID=58699224

Family Applications (1)

Application Number Title Priority Date Filing Date
US16/484,367 Abandoned US20200032369A1 (en) 2017-02-10 2018-02-08 Method of operating a pelletizing plant

Country Status (8)

Country Link
US (1) US20200032369A1 (fr)
EP (1) EP3580362A1 (fr)
CN (1) CN110300809A (fr)
BR (1) BR112019016523A2 (fr)
EA (1) EA201991841A1 (fr)
LU (1) LU100075B1 (fr)
TW (1) TW201835341A (fr)
WO (1) WO2018146183A1 (fr)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3333951A (en) * 1965-06-14 1967-08-01 Mcdowell Wellman Eng Co Metallized pellets
US3754890A (en) * 1971-09-17 1973-08-28 Harsco Corp Process for producing metallized agglomerates and recovery of non ferrous values from waste materials
US3864119A (en) * 1973-10-01 1975-02-04 Allis Chalmers Method and apparatus for simultaneously producing large and small heat hardened agglomerates of mineral ore
GB9523229D0 (en) * 1995-11-14 1996-01-17 Allied Dust Processing Ltd Method of processing finely divided material incorporating metal based constituents
CN101613800B (zh) * 2009-07-17 2011-03-23 重庆瑞帆再生资源开发有限公司 采用两次成球方式制作的冶金复合球团、制备方法及应用
CN101717854B (zh) * 2009-12-25 2012-06-27 重庆瑞帆再生资源开发有限公司 利用冶金焙烧炉生产金属化球团的方法
JP2015096651A (ja) * 2013-10-22 2015-05-21 ヴァーレ、ソシエダージ、アノニマＶａｌｅ Ｓ．Ａ． 粗ペレットを改良する装置、およびペレット化方法

Also Published As

Publication number Publication date
LU100075B1 (en) 2018-10-02
CN110300809A (zh) 2019-10-01
WO2018146183A1 (fr) 2018-08-16
BR112019016523A2 (pt) 2020-03-31
TW201835341A (zh) 2018-10-01
EP3580362A1 (fr) 2019-12-18
EA201991841A1 (ru) 2020-01-22

Similar Documents

Publication Publication Date Title
CN101717854B (zh) 利用冶金焙烧炉生产金属化球团的方法
US8641799B2 (en) Process for producing agglomerates of finely particulate iron carriers
US8439987B2 (en) Method of producing carbonaceous material-containing briquettes using steel mill dust containing oil
RS20060207A (sr) Samo-redukujuće,hladno vezane granule
EP1338660A1 (fr) Granules verts contenant des oxydes metalliques pour four de reduction, procede de production de ces granules, procede de reduction de ces granules et installations de reduction
CN102137944B (zh) 用于由未经煅烧的锰矿石制备锰粒料的方法和由该方法得到的附聚物
KR20150071388A (ko) 소결광 제조 방법
US3759693A (en) Method of producing reduced iron ore pellets
AU2017388174B2 (en) Sintered ore manufacturing method
KR102217869B1 (ko) 과립의 제조 방법 및 제조 장치
JP5512205B2 (ja) 塊成化状高炉用原料の強度改善方法
JP3779009B2 (ja) 製鉄ダストからの高品位還元鉄の製造方法
JP6273983B2 (ja) 還元鉄を用いた高炉操業方法
EP1749894A1 (fr) Minerai semi-réduit fritté et sa méthode de production
US20200032369A1 (en) Method of operating a pelletizing plant
JP5103802B2 (ja) 湿ダストの処理方法及び焼結鉱の製造方法
EP0053139B1 (fr) Agglomeres leur procede de production et leur utilisation
YOSHIKOSHI et al. Development of composite cold pellet for silico-manganese production
JP4600102B2 (ja) 還元鉄の製造方法
Rao Agglomeration and prereduction of ores
US3864119A (en) Method and apparatus for simultaneously producing large and small heat hardened agglomerates of mineral ore
RU2095435C1 (ru) Способ подготовки агломерационной шихты к спеканию
JP6988778B2 (ja) 炭材内装焼結鉱の製造方法および炭材内装焼結鉱の製造設備
JP2003277840A (ja) 塊鉱石の高炉原料化処理方法
JPS61207526A (ja) 還元性にすぐれた製鉄原料の製造法

Legal Events

Date Code Title Description
AS Assignment

Owner name: PAUL WURTH S.A., LUXEMBOURG

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STRUEBER, GEORG;NOUAILLE-DEGORCE, GILLES;SIGNING DATES FROM 20190617 TO 20190621;REEL/FRAME:049993/0253

STPP Information on status: patent application and granting procedure in general

Free format text: APPLICATION DISPATCHED FROM PREEXAM, NOT YET DOCKETED

STPP Information on status: patent application and granting procedure in general

Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION