High graphite cathode charcoal piece and production method thereof
Technical field
The present invention relates to a kind of cathod carbon block used in aluminium electrolytic bath, particularly high graphite cathode charcoal piece and production method thereof.
Background technology
The part that contacts with ionogen with aluminium liquid in the aluminium cell is to build by laying bricks or stones with cathode carbon pieces to form, in electrolytic process, cathode carbon pieces is a negative electrode, also be directly to contact simultaneously with aluminium liquid, ionogen, the life-span of cathode carbon pieces will directly have influence on the life-span of aluminium cell, that cathode carbon pieces must possess is high temperature resistant, the characteristic of refractory salt corrosion and conduction, good heat conductivity, also needs high physical strength simultaneously, good thermal shock, the strong characteristics of anti-sodium aggressiveness.
At present, industry member is divided three classes cathode carbon pieces: hard coal cathode carbon pieces, graphite cathode carbon block, graphitized cathode carbon block.And the hard coal cathode carbon pieces is divided into amorphous and semi-graphite charcoal piece two big classes according to its degree of graphitization, because the conductivity and the anti-sodium erosion performance of amorphous-type are all relatively poor, causes in the electrolytic process power consumption big, and lack bath life.
The development trend of cathode carbon pieces is to improve content of graphite at present, to improve the over-all properties of cathode carbon pieces, as disclosed " manufacture method of cathod carbon block used in aluminium electrolytic bath " (patent No.: patent application 91100789.X) by name in Patent Office of the People's Republic of China's on October 2nd, 1991, it be with hard coal, Zhi Jinjiao after the calcining, few ash is burnt, graphite is broken or scale graphite is an aggregate, binding agent is a pitch, behind the kneading and compacting, carry out semi-graphited and the cathode carbon pieces that forms.The cathode carbon pieces that utilizes this side to produce has the low characteristics of resistivity, but because its compressive strength is lower, work-ing life is short, will cause the work-ing life of aluminium cell relatively low.
Summary of the invention
The invention provides and a kind ofly have high electrical conductivity and higher anti-sodium erosion performance, and physical strength and high thermal resistance cathode carbon pieces and manufacture method thereof preferably.
Technical scheme of the present invention is: a kind of high graphite cathode charcoal piece, comprise aggregate, bituminous cement, and it is characterized in that cathode carbon pieces is that the 15-30% roasting is broken by the 30-60% electric calcined anthracite of granularity less than 8 millimeters, 10-50% graphite and 15-25% pitch are formed.
The granularity of above-mentioned graphite is preferably less than 6 millimeters.
The broken size-grade distribution of above-mentioned electric calcined anthracite and roasting is: less than 1 millimeter: 20-50%; 4-1 millimeter: 20-40%, 4-8 millimeter: 20-40%.
A kind of method of producing high graphite cathode charcoal piece, comprise batching, mix pinch, moulding, roasting, it is characterized in that:
A, batching and mix and to pinch: after in proportion that electric calcined anthracite, roasting is broken, graphite mixes, add the pitch of 15-25%, mix at 100-160 ℃ and pinched 60-120 minute;
B, moulding: adopt extrusion molding, temperature remains on 100-180 ℃ during moulding.
C, roasting: with the cathode carbon pieces of moulding, put into stoving oven and carry out roasting, heat up and soaking time 360-400 hour top temperature 1200-1300 ℃.
Characteristics of the present invention are:
1. electric conductivity is higher: cathode carbon pieces content of graphite of the present invention is higher, so its electric conductivity is higher, can effectively reduce the power consumption of electrolytic aluminum process.
2. anti-sodium aggressiveness is good: because the granularity of various compositions is less in the charcoal piece, particularly the granularity of graphite is lower, and the granularity of various compositions has been carried out the proportioning of science, make the compacted density of charcoal piece bigger, sodium has prolonged the work-ing life of charcoal piece to the erosion action of charcoal piece in the electrolytic process thereby can effectively reduce.
3. owing to aggregate size and aggregate and bituminous proportion relation are selected reasonable, and be equipped with the working method of science, thereby the physical strength of charcoal piece and high thermal resistance are enhanced.
Description of drawings
Accompanying drawing 1 is technological process of production figure of the present invention.
Embodiment
Embodiment one:
As shown in Figure 1,43% electric calcined anthracite, 15% roasting is broken, 25% graphite mixes the back to be mixed with 17% pitch and pinches, and kneading temperature is 128 ± 5 ℃, mixed pinching 110 minutes time.Wherein, the size-grade distribution such as the following table of broken, the graphite of electric calcined anthracite, roasting:
Granularity (mm) | Electric calcined anthracite | Roasting is broken | Graphite |
Less than 1 | 50% | 20% | 30% |
1-4 | 20% | 50% | 70% |
4-8 | 30% | 30% | |
Add extrusion molding in the extrusion machine with mixing the batching of pinching, temperature remains on 100 ℃ during moulding.With the cathode carbon pieces of moulding, put into stoving oven and carry out roasting, by 300 hours temperature is raised to 1300 ℃, be incubated after 50 hours, after room temperature, be finished product gradually.
Embodiment two:
As shown in Figure 1,30% electric calcined anthracite, 18% roasting is broken, 32% graphite mixes the back to be mixed with 20% pitch and pinches, and kneading temperature is 155 ± 5 ℃, mixed pinching 60 minutes time.Wherein, the size-grade distribution such as the following table of broken, the graphite of electric calcined anthracite, roasting:
Granularity (mm) | Electric calcined anthracite | Roasting is broken | Graphite |
Less than 1 | 30% | 40% | 30% |
1-4 | 40% | 30% | 50-70% |
4-8 | 30% | 30% | |
Add extrusion molding in the extrusion machine with mixing the batching of pinching, temperature remains on 180 ℃ during moulding.With the cathode carbon pieces of moulding, put into stoving oven and carry out roasting, by 350 hours temperature is raised to 1200 ℃, be incubated after 50 hours, after room temperature, be finished product gradually.
By the cathode carbon pieces that above method is produced, its main performance index can reach: ash content<3%, volume density: 1.5-1.8g/cm
3, resistivity: 30-35 μ Ω m, compressive strength>30Mpa.