CN1026646C

CN1026646C - Technology and apparatus for producing hollow graphite electrode by vibration shaping

Info

Publication number: CN1026646C
Application number: CN 91108416
Authority: CN
Inventors: 郑军
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-10-28
Filing date: 1991-10-28
Publication date: 1994-11-16
Anticipated expiration: 2006-10-28
Also published as: CN1060429A

Abstract

The present invention relates to a moulding technology for hollow graphite electrodes, and an apparatus thereof. Petroleum coke, coal asphaltum and asphaltum coke are used as raw materials, are calcined, pulverized, sieved, prepared into paste, heated to 120 to 130 DEG C, and are filled in the annular cross section of a coaxial casing pipe type steel mould. Under 1.0 to 1.5 kg/centimeters<2> of pressure, after the paste is vibrated for 7 to 8 minutes at the speed of 2500 to 3000 times/minute, the paste is pushed out of the steel mould, cooled, calcined and processed in a graphitization mode and is processed into the required size in a mechanical mode. The casing pipe type steel mould is composed of a circular outer sleeve steel tube 2, a coaxial core tube 4 with required diameter and a circular steel plate 5 with a top point. The diameter of the circular steel plate 5 is equal to or slightly smaller than the inside diameter of the outer sleeve pipe. The hollow electrode made by the method has the advantages of high rate of finished product and no crack, and the specific resistance, the intensity and the specific gravity of the hollow electrode completely conform to smelting requirements.

Description

Technology and apparatus for producing hollow graphite electrode by vibration shaping

The present invention relates to the production method of electric furnace smelting, particularly relate to the manufacture method of the big graphite electrode of intermediate hollow with graphite electrode.

Along with electric furnace steel making and silicon metal, the increase of electric furnace power such as yellow phosphorus, artificial graphite electrode also will develop towards big specification direction.The increase of electrode diameter, make electrode in moulding, roasting graphitization process,, and cause percent defective to increase greatly because of thermal stress cracks.At present, each charcoal ink factory: the percent defective of the artificial graphite electrode of the above specification of 400mm is much higher than the electrode of the following specification of ∮ 350mm, and ∮ 400mm is longer than the electrode of ∮ 350mm and following specification with the roasting and the graphitization curve of top electrode, so just increase unit consumption, reduced output.

In order to reduce the heating region and the efficiency of heating surface that electrode thermal shock in use and electric and magnetic oscillation improve graphite electrode, EPO, 193,918, EP0.082,678, US3,422,205, US3,231,177, refer to the structure and the use of graphite heating pipe, but do not introduced the manufacturing process of hollow graphite electrode.

The objective of the invention is with petroleum coke, coal tar pitch, pitch coke is the method and apparatus that raw material is produced a kind of intermediate hollow electrode, it is excessive and the drawback of crackle takes place to improve electrode thermal stress in heat treatment, reduce percent defective, shorten roasting and graphited curve, consumption reduction volume increase.Improve impregnated electrode rate of body weight gain, reduce the loss of sheet accident that electrode in use produces because of thermal shock and electric and magnetic oscillation.

The production method of hollow electrode of the present invention is to produce on the basis of single shaft or the upright shaped electrode technology of shaking of dual-axis vibration platform, the general technology process is to be raw material with petroleum coke (70 parts), coal tar pitch (25 parts), pitch coke (5 parts), through calcine, crush and screen, batching, mixing become thickener to be heated in the external diameter of the 120-130 ℃ of coaxial sleeve tube punching block of packing into and the annular space between the central hollow tube (core pipe) (referring to accompanying drawing), in 101.5 kilograms per centimeter ²Pressure, vibrate 2500-3000 time/minute under, after vertical vibrating 7-8 minute, the electrode material is released from punching block, water cooling become parison, carry out roasting again, graphitization processing is machined into required size.Its characteristics are to vibrate compression moulding and adopt a coaxial sleeve tube punching block.Promptly at the center of circular punching block, put the stainless steel tube (core pipe) of a suitable diameter perpendicular to table top, its diameter of steel tube is decided on the size of electrode diameter, and install a round plate that equates with punching block (outer tube) internal diameter at the table top centre bit, it is top that round plate central vertical weldering one equates with stainless steel core bore, top being inserted in the core pipe.During moulding, the upper end of core pipe is enclosed within the centre bore of electrode pressure cap, and the lower end is inserted in on the top circular steel plate.At this moment, start bobbing machine, cooperate the pasty state material to add continuously in the punching block prepared electrode, after punching block is filled it up with, promptly slowly fall weight, the pressure cap below the weight is pressed in the punching block, pick up counting this moment, shuts down the demoulding after 8 minutes.During the demoulding, earlier weight and pressure cap are mentioned, the punching block that fell again transfers to steel pipe to pass through top cap 9 with demoulding plunger again in horizontal level then, the electrode base is released from punching block, and the trickle cooling gets final product rapidly.

Accompanying drawing is a hollow graphite electrode moulding process sketch

Fig. 1, reinforced completed state diagrammatic sketch;

Fig. 2 falls weight completed state diagrammatic sketch;

Fig. 3, demoulding state diagram.

The number in the figure sign, 1 punching block, 2 heating collars (outer tube), 3 thickeners, 4 hollow steel pipes (core pipe), 5 are with top round plate, 6 vibration machines, 7 weights, 8 cool material platforms, 9 top caps, 10 demoulding plungers.

Embodiment gets 70 parts of raw material petroleum cokes,, cools off after about 17 hours in 1300 ℃ of temperature lower calcinations in the continuous calcining stove behind 5 parts of mixings of pitch coke, broken, levigate, screening.Press particle composition＜0.075mm60% again, 0.8-1.0mm11%, 1-2mm14%, 2-4mm15%(weight) prepare burden, the siccative for preparing is added preheating in the mixed kneading machine, when temperature reaches 120 ℃ of left and right sides, add 25 parts of coal tar pitch after the fusing dehydration, mix and pinch, the pasty state material of certain plasticity is evenly arranged, add then in the aforementioned punching block at 1-1.5kg/cm pressure, vibrate vibration moulding under 2500-3000 time/minute condition, vibration moulding and stripping operation are undertaken by preceding method, obtain the electrode green compact of hollow, place baking furnace 0-1350 ℃ of roasting about 400 hours on green compact, in graphitizing furnace, under 2500-3000 ℃ high temperature, carry out graphitization again, carry out machining after taking out cooling, electrode cylindrical and end are processed into required size, obtain the artificial graphite electrode finished product of hollow.The electrode hollow section accounts for the long-pending 1-25% of electrode sections, is guaranteed output, the long-pending 1-10% that accounts for electrode sections of best hollow section.

The performance of the hollow artificial graphite electrode that obtains like this is not less than 9mm than resistance ²/ m, rupture strength is not less than 75kg/cm ², compression strength is not less than 180kg/mm ², true specific gravity reaches 2.18g/cm ³, flawless.

Claims

1, a kind of hollow graphite electrode forming method, press 70 parts of petroleum cokes, 5 parts of mixing of pitch coke, calcined 17 hours down at 1300 ℃, cooling, levigate screening, press particle composition＜0.075mm60%, 0.8-1.0mm11%, 1-2mm14%, 2-4mm15% (weight) prepares burden, in mixed kneading machine, be heated to 120 ℃, add 25 parts of mixed thickeners of pinching into of the coal tar pitch after the fusing dehydration, it is characterized in that thickener is heated in the outer tubulature and the annular space between the core pipe of the 120-130 ℃ of coaxial sleeve tube punching block of packing into continuously, fill it up with the back and use weight in the 1.0-1.5 kilograms per centimeter ²Pressure, vibrate 2500-3000 time/minute under, upright after vibrational 7-8 minute, with the electrode material from copper mold, release, water cooling gets final product.

2, a kind of punching block that is used for the described hollow graphite electrode forming method of claim 1, be characterized in a coaxial sleeve tube punching block, it is by round jacket pipe 2, the coaxial hollow steel pipe of required diameter is that 4, one central vertical of core pipe are welded with a top round plate that equates with hollow steel pipe 4 internal diameters 5 compositions.Top being inserted in the core pipe, round plate 5 diameters equate with the internal diameter of outer tube 2.