CN1007044B - Melted metal surface heat-generating isolation agent - Google Patents
Melted metal surface heat-generating isolation agentInfo
- Publication number
- CN1007044B CN1007044B CN 86100805 CN86100805A CN1007044B CN 1007044 B CN1007044 B CN 1007044B CN 86100805 CN86100805 CN 86100805 CN 86100805 A CN86100805 A CN 86100805A CN 1007044 B CN1007044 B CN 1007044B
- Authority
- CN
- China
- Prior art keywords
- heat generating
- agent
- metal
- rice husk
- casting
- 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.)
- Expired
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Abstract
The present invention relates to a heat generating insulation agent which can be applied to the field of metallurgy and casting. The heat generating insulation agent adopts carbonation rice hulls as a principal raw material, and an oxydant with a certain proportion is added to the principal raw material to replace an original expensive metal heat generating agent containing aluminium, etc. The disadvantages of short heat generating time, wide temperature fluctuation range and poor insulating performance of the original metal heat generating agent are overcome. The price of the heat generating insulation agent is far lower than that of the metal heat generating agent. The present invention has the characteristics of balanced heat generation, long duration time, no fly ash, no harmful gas pollution, etc. When used in the casting process of a steel ingot and a metal casting, the novel heat generating insulation agent can notably reduce the shrinkage cavity of the steel ingot and enhance the yield of the steel ingot and the qualification rate of the casting.
Description
The invention belongs to metallurgical field of metal casting technology, be used to cover molten iron or molten steel surface, in teeming or mechanical foundry goods process, play heating and insulation effect.
For improving steel quality and improving recovery rate of iron, when casting finishes, need to add exothermic mixture or heat preserving agent at steel ingot or foundry goods cap mouth.Since the beginning of the eighties, domestic steel mill extensive use metal mold exothermic mixture (clear 59-153549, su1072-992-A), mainly be made up of following three kinds of raw materials: combustion heating element, oxidant and insulation material by this exothermic mixture.The combustion heating element is metallic aluminium, Antaciron and calcium-silicon.Oxidant generally uses sodium nitrate, manganese ore powder and Iron Ore Powder.What the insulation material use was more is expanded perlite, vermiculite and acid treatment graphite.Preparation method is respectively to get one or more (with powder shapes) to mix by a certain percentage from these three kinds of raw materials.The consumption and the price of used metal and acidifying graphite are listed in table 1.
As can be seen from Table 1, the combustion heating element in the exothermic mixture is expensive metal or alloy.The Antaciron exothermic mixture that price is relatively cheap can cause ingot head to increase silicon during use, seriously influence steel product quality.So general steel mill adopts the aluminum metal exothermic mixture of higher calorific value.Metallic aluminium not only costs an arm and a leg but also is national goods and materials in short supply.An enterprise that produces 3000000 tons of steel per year, the aluminium that only is used for exothermic mixture in 1 year can reach 540 tons to 900 tons (with 15%Al in the exothermic mixture, consumption is 1.2kg～2.0kg/ ton steel meter).This shows that the iron and steel enterprise in the whole nation only is used to generate heat and will burns the metallic aluminium of considerable quantity.
In addition, the moment burning of being heated during the use of metal exothermic mixture, process is difficult to control.Insulation material vermiculite and expanded perlite etc. are because fusing point is low, vitreous clinker when metal burning, and lose the effect of insulation.The best expanded graphite of heat-insulating property is that acidifying graphite is that graphite cleans behind sulfuric acid and nitric acid mixed liquid dipping, dries and make.This raw material complex manufacturing technology, environmental pollution is serious, and price is expensive.
The steel plant that have in the industrial production are at ladle and ladle or ingot head opening interpolation heat preserving agent.This heat preserving agent mainly is made up of following raw material: (clear 53-100919) such as expanded vermiculite, coke, graphite, carbonization rice husks.This class heat preserving agent only plays insulation effect basically on the liquid metals surface.Though wherein main component such as coke and carbonization rice husk is a combustible element carbon, owing to there is not oxidant combustion-supporting, calorific capacity is very low, and result of use is not good, especially when being used for middle-size and small-size steel ingot casting.
The objective of the invention is under the prerequisite that guarantees to satisfy to liquid metals surface heat supply and insulation, to reduce the cost of exothermic mixture, reduce metallurgical consumption with aluminium and other alloy materials.Use aboundresources, process simple and easyly, the honest and clean work of cheap carbonization rice husk generates heat and insulation material, thus the substituted metal exothermic mixture.
The present invention is base stock with the carbonization rice husk, allocate a certain amount of oxidant (as potassium nitrate, sodium nitrate, manganese oxide, manganese ore powder, Iron Ore Powder or iron oxide dust etc.) and plant binding agent into, its amount is: carbonization rice husk 55-95%(weight), oxidant 0.1-40%(weight), plant binding agent 0-20%(weight), dry after drying or make any needed shape after adding suitable quantity of water (wetting state) is mixed, bake out temperature is 120～160 ℃, places the liquid metals surface can play heating and insulation effect this product during use.
The base stock carbonization rice husk is that rice husk is put into specific simple mechanism, gets by self-heating destructive distillation carbonization.Its preparation method is simple, the source of not consuming energy.China abounds with rice, and the rice husk source is abundant, cheap.The composition of about 600 yuan/ton carbonization rice husk is as shown in table 2.
The used binding agent of the present invention selects for use the source abundant, low price, and the plant binding agent that nontoxic nothing is smelt during use is as ground rice, flour and starch etc.
The preparation method of heat preservation agent of the present invention is: add one or two or more kinds oxidant (wt%): NaNO in carbonization rice husk
3(or KNO
3) 0.1～30, manganese ore powder (or oxidation manganese powder) 0～35, Iron Ore Powder (or iron oxide dust) 0～40.With plant binding agent 0.1～20%, add suitable quantity of water (wetting state) again and in batch mixer, mix, make oxidant be wrapped in the carbonization rice husk outside equably, if product requirement is the shape form of loosing, material comes out just can directly dry from batch mixer.If product requirement is tabular or other forms, then the carbonization rice husk of mixed oxidant and binding agent is sent in the make-up machine, (as certain ingot head opening size dimension) makes the tabular of 5～400mm or its shape that needs on request.Discharge for ease of metal bath surface gas, some pores are arranged on the large-area plate.Carbonization rice husk goods after the moulding are drying again.
Bake out temperature is 120～160 ℃.
During use heat preservation agent is placed the surface, deposite metal, binding agent is burnt under the high temperature, and carbonization rice husk covers the molten metal surface just fluffyly.Permeate sodium nitrate in the carbonization rice husk inner pore etc. attached to the oxidant of carbonization rice husk outside and owing to being dissolved in water, decomposes discharges oxygen such as 2NaNO
3→ Na
2O+2NO
2+ 1/2O
2Make the carbon burning in the carbonization rice husk, redox reaction such as Fe perhaps take place
2O
3+ C → 2FeO+CO and emit heat.The calorific capacity that records the pure carbon rice husk with bomb method is 2575 kilocalories/kilogram, and table 3 is listed the calorific capacity of carbonization rice husk and some metal exothermic mixtures.
As seen had under the situation of sufficient oxygen by table, the calorific capacity of carbonization rice husk can match in excellence or beauty with the metal exothermic mixture fully, to satisfy the needs to deposite metal surface heat supply.Keep loose SiO after the carbon burning
2Play insulation effect.Because the carbonization rice husk hole is many, thermal conductivity is little, and when the carbonization rice husk of contact melting metal burnt, the unburned carbonization rice husk in top had good heat-insulating property, has stoped the heat of burning and deposite metal outwards to be distributed.Because oxidant is bonded on the carbonization rice husk equably, thereby has guaranteed that oxygen supply is even in the combustion process, makes the carbonization rice husk layering to the top smoulder.So just can be according to the addition that increases or reduce oxidant, and the proportioning of regulating different oxidants, heating of the present invention and heat-insulating property controlled effectively.
Metal exothermic mixture with heat preservation agent of the present invention and pure carbon rice husk and different heat element has carried out the contrast experiment in induction furnace.When different exothermic mixtures or heat preserving agent are placed in the molten iron surface, the variation of 3-5mm depths, measuring distance molten iron surface molten iron temperature, as shown in drawings.Curve 1 is heat preservation agent of the present invention among the figure, experiment consumption 25 grams, and curve 2 is the pure carbon rice husk, experiment consumption 25 grams.Curve 3 is containing metal aluminium 13-16(wt) the metal exothermic mixture of %, the experiment consumption is 50 grams.Curve 4 is for containing ferrosilicon powder 60(wt) the metal exothermic mixture of %, the experiment consumption also is 50 grams.Testing 1290 ℃ begins exothermic mixture (or heat preserving agent) is dropped into the molten iron surface, under the situation of heat of stopping power supply, observe molten iron surface cooling process, experiment finishes during to 1190 ℃, and be recorded in these 100 ℃ of various heatings of temperature descending section (insulation) required time of agent, time is long more, illustrates that its heat insulation effect is good more.By accompanying drawing as seen, comprehensive heat preservation effect of the present invention is best.Behind heat preservation agent contact molten iron, both do not resembled the absorbing and cooling temperature peak value that occurs being harmful to the ingot casting process the aluminum metal exothermic mixture, no-good high thermal peak does not appear yet, and process is the smoulder heating.This heat preservation agent is imitated well with the insulation of metal exothermic mixture (curve 3 and 4).Compare with the pure carbon rice husk (curve 2),, cause the molten iron surface temperature higher 50～70 ℃ than the molten iron temperature under the pure carbon rice husk thermal insulation because the present invention has heating functioin.
Therefore, fully can the substituted metal exothermic mixture with the carbonization rice husk of oxidant, thus can save a large amount of metallic leads and other alloys, reduce the cost (can reach 50%) of exothermic mixture significantly.And heating effect of the present invention obviously is better than the pure carbon rice husk thermal insulation agent, enlarged the scope of application of carbonization rice husk.
Use heat preservation agent of the present invention, can satisfy on the surface, deposite metal and play the heat preservation effect.The phenomenon of not smoldering in the use, combustion process is stable, no dust and pernicious gas pollution.Can the same remarkable minimizing steel ingot with the metal exothermic mixture and foundry goods shrinkage cavity, improve steel ingot recovery rate and casting qualified rate.
The present invention can be used for covering ladle, ladle, continuous casting tundish, the heat preservation effect is played on the ingot head opening and the mechanical foundry goods cap mouth deposite metal surface of cast steel down.
Example 1(wt%)
Carbonization rice husk 75
NaNO
33
Manganese ore powder 8
Iron Ore Powder 12
Plant binding agent (as potato starch) 2
After adding suitable quantity of water mix in batch mixer in aforementioned proportion temperature compound, place 120～160 ℃ of oven dry beds to go up baking half an hour, the weighing pack of cooling back drops into the surface, deposite metal during use.Use amount is 40～70% of a virgin metal exothermic mixture.
Example 2(wt%)
Carbonization rice husk 80
NaNO
35
Iron oxide dust 10
Plant binding agent (ground rice 2, starch 3) 5
Aforementioned proportion temperature compound adds water in batch mixer, mix after, according to needed shape and size, in make-up machine, make the thick grain slice of 5～400mm or tabular, also can be made into the tabular of ingot head opening size dimension, have pore some on the plate.Drop into or hang in advance the cap mouth during use.
Table 1. exothermic mixture primary raw material consumption and price list
Name of an article price * (yuan/ton) content (wt) % in the exothermic mixture
Aluminium 5300～6,000 8～27
Antaciron 1,760 10～70
Calcium-silicon 3,200 5～15
Acidifying graphite 2700～3,600 5～9
* market price in 1985
Table 2. carbonization rice husk composition
Composition total carbon SiO2The S volatility
Content (wt) % 33.40 60.58 0.092 5.38
Table 3. metal exothermic mixture and pure carbonization rice husk calorific capacity
Heating composition % calorific capacity (kilocalorie/kilogram)
(bomb method measured value)
Si Al C powder
25 5 15 1874
20 10 15 1748
20 10 / 1591
Pure carbon rice husk 2575
Claims (2)
1, the heat preservation agent on surface, a kind of deposite metal, it is main component with the carbonization rice husk, and contain plant binding agent (as ground rice, flour, starch etc.), after adding water, mix and oven dry, it is characterized in that wherein allocating into one or more oxidant (as potassium nitrate, sodium nitrate, manganese oxide, manganese ore powder, Iron Ore Powder, iron oxide dust etc.), three kinds of compositions according to the proportioning of weight are: carbonization rice husk 55-95%, oxidant 0.1-40%, plant binding agent 0-20%.
2, as by the described heat preservation agent of claim 1, it is characterized in that the oxidant allocated into according to the proportioning of weight is: sodium nitrate (or potassium nitrate) is 0.1-30%, and manganese ore powder (or manganese oxide) is 0-35%, and Iron Ore Powder (or iron oxide dust) is 0-40%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86100805 CN1007044B (en) | 1986-02-03 | 1986-02-03 | Melted metal surface heat-generating isolation agent |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86100805 CN1007044B (en) | 1986-02-03 | 1986-02-03 | Melted metal surface heat-generating isolation agent |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN86100805A CN86100805A (en) | 1987-01-31 |
| CN1007044B true CN1007044B (en) | 1990-03-07 |
Family
ID=4801208
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 86100805 Expired CN1007044B (en) | 1986-02-03 | 1986-02-03 | Melted metal surface heat-generating isolation agent |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1007044B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102757240B (en) * | 2011-04-25 | 2013-09-04 | 宝山钢铁股份有限公司 | Heating panel used in steel ingot head heat insulation |
| CN102825224A (en) * | 2012-07-31 | 2012-12-19 | 马鞍山科润冶金材料有限公司 | Composite heat generating agent for weathering steel |
| CN107685140A (en) * | 2017-09-08 | 2018-02-13 | 河钢股份有限公司承德分公司 | A kind of method for reducing tundish covering flux consumption |
-
1986
- 1986-02-03 CN CN 86100805 patent/CN1007044B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN86100805A (en) | 1987-01-31 |
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