CN115321534B - Method for in-situ extraction of large-scale graphite from molten iron pretreatment desulfurization slag - Google Patents
Method for in-situ extraction of large-scale graphite from molten iron pretreatment desulfurization slag Download PDFInfo
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- 239000002893 slag Substances 0.000 title claims abstract description 173
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 133
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 81
- 230000023556 desulfurization Effects 0.000 title claims abstract description 81
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 71
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 69
- 239000010439 graphite Substances 0.000 title claims abstract description 69
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 66
- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000011065 in-situ storage Methods 0.000 title claims abstract description 22
- 238000000605 extraction Methods 0.000 title claims abstract description 17
- 238000003756 stirring Methods 0.000 claims abstract description 62
- 235000019738 Limestone Nutrition 0.000 claims abstract description 39
- 239000006028 limestone Substances 0.000 claims abstract description 39
- 239000002245 particle Substances 0.000 claims abstract description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 29
- 230000008569 process Effects 0.000 claims abstract description 19
- 238000005507 spraying Methods 0.000 claims abstract description 9
- 239000007788 liquid Substances 0.000 claims abstract description 7
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 5
- 238000000354 decomposition reaction Methods 0.000 claims description 21
- 238000007667 floating Methods 0.000 claims description 8
- 239000011593 sulfur Substances 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- 238000005054 agglomeration Methods 0.000 claims description 4
- 230000002776 aggregation Effects 0.000 claims description 4
- 238000001354 calcination Methods 0.000 claims description 4
- 230000003009 desulfurizing effect Effects 0.000 claims description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 3
- 238000010298 pulverizing process Methods 0.000 claims description 3
- 239000004575 stone Substances 0.000 claims description 2
- 238000011068 loading method Methods 0.000 claims 1
- 238000011084 recovery Methods 0.000 abstract description 18
- 235000008733 Citrus aurantifolia Nutrition 0.000 abstract description 4
- 235000011941 Tilia x europaea Nutrition 0.000 abstract description 4
- 230000008901 benefit Effects 0.000 abstract description 4
- 239000004571 lime Substances 0.000 abstract description 4
- 238000007885 magnetic separation Methods 0.000 abstract description 4
- 238000005516 engineering process Methods 0.000 abstract description 3
- 238000004064 recycling Methods 0.000 description 7
- 229910000831 Steel Inorganic materials 0.000 description 6
- 239000012071 phase Substances 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 238000005188 flotation Methods 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000003860 storage Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910021382 natural graphite Inorganic materials 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910004261 CaF 2 Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000000404 calcium aluminium silicate Substances 0.000 description 1
- 235000012215 calcium aluminium silicate Nutrition 0.000 description 1
- WNCYAPRTYDMSFP-UHFFFAOYSA-N calcium aluminosilicate Chemical compound [Al+3].[Al+3].[Ca+2].[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O WNCYAPRTYDMSFP-UHFFFAOYSA-N 0.000 description 1
- 229940078583 calcium aluminosilicate Drugs 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/21—After-treatment
- C01B32/215—Purification; Recovery or purification of graphite formed in iron making, e.g. kish graphite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/04—Recovery of by-products, e.g. slag
- C21B3/06—Treatment of liquid slag
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/04—Recovery of by-products, e.g. slag
- C21B3/06—Treatment of liquid slag
- C21B3/08—Cooling slag
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2400/00—Treatment of slags originating from iron or steel processes
- C21B2400/02—Physical or chemical treatment of slags
- C21B2400/022—Methods of cooling or quenching molten slag
- C21B2400/024—Methods of cooling or quenching molten slag with the direct use of steam or liquid coolants, e.g. water
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Manufacturing & Machinery (AREA)
- Environmental & Geological Engineering (AREA)
- Inorganic Chemistry (AREA)
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Abstract
The invention discloses a method for in-situ extraction of large-scale graphite from molten iron pretreatment desulfurization slag, which comprises the following steps of 1) adding small-particle lime into a molten iron ladle according to 0.5-0.7 kg of ton of iron before stirring is finished, wherein the desulfurization agent is added according to a KR pretreatment process and stirred according to a determined stirring time; 2) Lifting the stirring head until the lower end surface of the stirring head is level with the liquid level of the molten iron, and continuing stirring to uniformly mix the small-particle limestone in the iron slag; 3) After stirring, normal slag skimming operation is carried out according to the desulfurization process requirement, and after slag skimming is finished, the slag ladle is opened, and the slag ladle is transported to a slag field; 4) Pouring the slag pot to spread the desulfurization slag on the ground, and spraying with water; 5) The sprayed desulfurization slag is put into a water tank by a forklift, and is continuously stirred by a bucket to break up large slag blocks. The invention avoids the damage of the traditional technologies such as crushing, magnetic separation and the like to the scales, realizes the in-situ extraction and recovery of the large-scale graphite, improves the recovery quantity and recovery efficiency of the scale graphite in the slag, and has remarkable economic benefit.
Description
Technical Field
The invention relates to the technical field of comprehensive utilization of resources, in particular to a technology for separating and recycling graphite in molten iron pretreatment desulfurization slag, and particularly relates to a method for in-situ extraction of large-scale graphite from molten iron pretreatment desulfurization slag.
Background
With the increasing demand of people for clean steel, low-sulfur steel and ultra-low-sulfur steel, more and more iron and steel enterprises begin to pay attention to the molten iron pretreatment process to pre-desulphurize molten iron. At present, the domestic hot metal pretreatment desulfurization process mainly comprises two modes of a blowing method and a KR stirring method, wherein the KR stirring method has the advantages of high desulfurization efficiency, low consumption of desulfurizing agent and refractory materials, low hot metal temperature reduction, low cost and the like, and is accepted by most iron and steel enterprises.
The steelmaking desulfurization slag refers to waste slag generated in the pre-desulfurization treatment of molten iron before the molten iron enters a converter. Compared with converter slag and blast furnace slag, recycling of KR desulfurization slag is not paid attention to in China at present, metal recovery is generally carried out after magnetic separation, tailings are used as sintering raw materials or are treated together with other steel slag, the recycling level is not high, meanwhile, researches on related physicochemical properties of the desulfurization slag are relatively less in China, and targeted recycling of the desulfurization slag is also influenced.
The main component of KR desulfurization slag is CaO and SiO 2 、Fe、CaF 2 、Al 2 O 3 MgO, caS, etc.; based on the reason of ore components, part of KR desulfurization slag of part of metallurgical enterprises also contains part of TiO 2 And V 2 O 5 Etc., caO mass fraction even exceeds 50%, caO/SiO 2 The mass ratio is about 3.5, the mass fraction of the cas is 1.0% -2.5%, and part of metal particles carried in the slag are also carried in. The mineral composition of the desulphurized slag mainly comprises a calcium aluminosilicate phase, a calcium silicate phase, a spinel compound phase, a metal iron phase and a CaS phase, and the main phase of the desulphurized slag at high temperature (1673K to 2073K) is Ca 3 SiO 5 CaS and liquid phase, during cooling, due to Ca 3 SiO 5 Stable, easy to decompose to form C 2 S and CaO, C 2 S is easy to generate crystal form transformation, so that the volume of KR desulfurization slag is expanded,so that the KR desulfurization slag is pulverized in the cooling process.
In the process of tapping the molten iron in a blast furnace, transferring the molten iron and pre-treating KR, carbon elements in the molten iron are supersaturated and precipitated in different proportions due to the change of the temperature and the thermal history of the molten iron and the related physical kinetic energy conditions, and the purified concentrated flake graphite has the same performance as natural graphite and even has better service performance in certain specific fields than the natural graphite. The value of the graphite is represented by the size of graphite flake, the larger the flake is, the lower the friction coefficient is, the more excellent performances such as floatability, lubricity, plasticity and the like are, and the higher the value is. In the production of flake graphite, large-flake graphite can only be extracted from raw ores, and the modern industrial technology cannot produce synthetic large-flake graphite, so that the flake cannot be recovered once damaged.
The desulfurization process is optimized by analyzing the precipitation conditions of the large-scale graphite in the desulfurization slag and the components and properties of the desulfurization slag, the large-scale graphite in the desulfurization slag is subjected to protective separation and in-situ extraction, the emerging sources of the large-scale graphite are expanded, and the method has remarkable economic value and strategic significance.
However, in the prior art, carbon in molten iron is saturated to precipitate to form flake graphite with different sizes, and the stirring of the stirring head accelerates precipitation and floating of graphite in the KR pretreatment process, and the graphite is mixed in desulfurization slag and enters a slag basin through slag skimming. Due to the physical properties of the desulfurization slag and the metal brought by stirring and slag skimming, the desulfurization slag is easy to agglomerate, and the recovery quantity and recovery efficiency of crystalline flake graphite in the slag are seriously affected.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a method for in-situ extraction of large-scale graphite from molten iron pretreatment desulfurization slag. According to the composition and characteristic research of the desulfurization slag, small-particle limestone is added in the later stage of KR pretreatment to modify the desulfurization slag, the desulfurization slag is poured into a slag field to carry out spray cooling and small-particle limestone decomposition reaction, then the desulfurization slag enters a water tank to be washed, and the crystalline flake graphite is floated and then enters a flotation process to recycle the crystalline flake graphite. The method avoids the damage of the conventional crushing, magnetic separation and other processes to the scales in the prior art, realizes the in-situ extraction and recovery of the large-scale graphite, improves the recovery quantity and recovery efficiency of the scale graphite in the slag, and has very remarkable economic benefit.
The technical scheme adopted for solving the technical problems is as follows:
a method for extracting large-scale graphite in situ from molten iron pretreatment desulfurization slag comprises calculating and adding desulfurizing agent according to initial sulfur content of molten iron and desulfurization target requirement according to normal KR pretreatment process, stirring with stirring head according to determined stirring time,
1) Before stirring, adding small-particle lime into the ladle according to 0.5-0.7 kg of ton iron;
2) Lifting the stirring head until the lower end surface of the stirring head is level with the liquid level of the molten iron, and continuing stirring to uniformly mix the small-particle limestone in the iron slag;
3) After stirring, normal slag skimming operation is carried out according to the desulfurization process requirement, and after slag skimming is finished, the slag ladle is opened, and the slag ladle is transported to a slag field;
4) Pouring the slag pot to spread the desulfurization slag on the ground, and spraying with water;
5) The sprayed desulfurization slag is put into a water tank by a forklift, and is continuously stirred by a bucket to break up large slag blocks.
The adding mode of the step 1) can adopt automatic feeding of a storage bin or manual feeding, and the automatic feeding of the storage bin needs to be weighed in advance for standby and is also prepared in advance by throwing manually.
The granularity of the stone small-particle limestone in the step 1) is required to be 5-10 mm.
The rotational speed of the stirring head in the step 2) is controlled to be 100-110 r/min, and the stirring time is controlled to be 3-4 min.
And 3) lifting the slag pot to a slag yard through a travelling crane after slag skimming is completed.
The small-particle limestone added in the later pretreatment stage in the step 4) is uniformly mixed in the iron slag after being stirred by a stirring head at a higher temperature, the temperature is suitable for the calcination and decomposition of the limestone, and the limestone is continuously decomposed in a slag pot after slag skimming to be decomposed into CaO and C0 2 Continuous decomposition of limestone, C0 2 And the continuous discharge can effectively inhibit the agglomeration of iron slag, and CaO decomposed after being sprayed in a slag field is pulverized by water, so that the hardening of the iron slag is further inhibited.
And 5) the CaO obtained after limestone decomposition in the step is pulverized by water, so that good conditions are created for floating up graphite precipitated in the desulfurization slag in a water pool, flake graphite with different sizes floats in water, and then grading floatation is carried out, so that the original size of graphite flakes is protected, and the in-situ large-flake graphite is recovered in time.
The beneficial effects of the invention are as follows:
1. according to the invention, the small-particle limestone is added in the later period of KR pretreatment to modify the desulfurization slag, the small-particle limestone is poured into a slag field to carry out spray cooling and small-particle limestone decomposition reaction, then the small-particle limestone is put into a water tank to be washed, and the scale graphite is put into a flotation process to recover the scale graphite after floating up, so that the damage of the traditional crushing, magnetic separation and other processes to the scale is avoided, the in-situ extraction and recovery of large-scale graphite are realized, the recovery quantity and recovery efficiency of the scale graphite in the slag are improved, and the economic benefit is very remarkable.
2. The invention combines the temperature of the desulfurization slag and the decomposition temperature of the small-particle limestone, and utilizes the decomposition products CaO and C0 of the small-particle limestone 2 The method effectively inhibits the hardening of the desulfurization slag, avoids the damage of the later-stage desulfurization slag crushing and the like to the large-scale graphite precipitated in the desulfurization slag, solves the problem that the large-scale graphite in the agglomerated desulfurization slag cannot be extracted and utilized, improves the recovery amount and recovery efficiency of the large-scale graphite in the desulfurization slag, and improves the efficiency of in-situ extraction of the large-scale graphite from the molten iron pretreatment desulfurization slag.
3. The invention spreads the desulfurization slag on the ground by pouring the slag pot, and sprays the desulfurization slag with water.
At the moment, the temperature of the desulfurization slag is higher, which is favorable for promoting limestone decomposition, and has small granularity, large reaction interface and quick reaction. Small-particle limestone added in the later stage of pretreatment is uniformly mixed in iron slag after being stirred by a stirring head, and the temperature is suitable for calcination and decomposition of the limestone. After slag skimming, the slag is continuously decomposed into CaO and C0 in a slag pot 2 C0 due to continuous decomposition 2 Continuous discharge, effectively inhibits the agglomeration of iron slag and slag fieldThe decomposed CaO after spraying is pulverized when meeting water, so that the hardening of iron slag is further inhibited.
4. The invention loads the sprayed desulfurization slag into a water tank, and the bucket continuously stirs and breaks the large slag blocks. C0 decomposed due to the decomposition of the earlier stage small particle limestone 2 Continuously discharging, pulverizing decomposed CaO when meeting water, creating good condition for floating up graphite precipitated in desulfurization slag in a pool, floating flake graphite with different sizes in water, then carrying out classified floatation, protecting original size of graphite flake to the greatest extent, and realizing timely recovery of in-situ large flake graphite.
Drawings
FIG. 1 is a schematic process flow diagram of an embodiment of the present invention.
Detailed Description
In order to make the technical solution of the present invention better understood by those skilled in the art, the technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments.
Example 1
Referring to fig. 1, a method for in-situ extraction of large-scale graphite from molten iron pretreatment desulfurization slag comprises the following steps of calculating and adding a desulfurizing agent addition amount according to initial sulfur content of molten iron and desulfurization target requirements according to a normal KR pretreatment process flow, stirring at normal rotation speed of a stirring head, and determining stirring time:
1. before stirring, adding small-particle lime into a ladle according to 0.5-0.7 kg of ton iron, wherein the particle size of the small-particle lime is required to be 5-10 mm;
the adding mode can adopt automatic feeding of a storage bin or manual feeding, and the automatic feeding of the storage bin needs to be weighed in advance for standby and manually thrown in advance.
2. Lifting the stirring head until the lower end surface of the stirring head is level with the liquid level of the molten iron, and continuing stirring to uniformly mix the small-particle limestone in the iron slag. At the moment, the iron slag has higher temperature and relatively better fluidity, and the small-particle limestone is uniformly mixed in the iron slag.
The rotating speed of the stirring head is controlled to be (100-110 r/min), and the stirring time is controlled to be 3-4 min;
3. and after stirring, carrying out normal slag skimming operation according to the desulfurization process requirement. After the slag skimming is finished, the slag pot truck is opened, and the slag pot is transported to a slag yard through a crane and the like.
4. Pouring the slag pot to spread the desulfurization slag on the ground, and spraying with water.
At the moment, the temperature of the desulfurization slag is higher, so that the limestone decomposition is promoted, the decomposition is fastest at the temperature of 1000-1300 ℃, and the smaller the granularity, the larger the reaction interface and the faster the reaction. Small-particle limestone added in the later stage of pretreatment is uniformly mixed in iron slag after being stirred by a stirring head, and the temperature is suitable for calcination and decomposition of the limestone. After slag skimming, the slag is continuously decomposed into CaO and C0 in a slag pot 2 C0 due to continuous decomposition 2 The continuous discharge effectively inhibits the agglomeration of the iron slag, and CaO decomposed after being sprayed in a slag field is pulverized when meeting water, so that the hardening of the iron slag is further inhibited.
5. The sprayed desulfurization slag is put into a water tank by a forklift, and is continuously stirred by a bucket to break up large slag blocks.
C0 decomposed due to the decomposition of the earlier stage small particle limestone 2 Continuously discharging, pulverizing decomposed CaO when meeting water, creating good condition for floating up graphite precipitated in desulfurization slag in a pool, floating flake graphite with different sizes in water, then carrying out classified floatation, protecting original size of graphite flake to the greatest extent, and realizing timely recovery of in-situ large flake graphite.
In the case, the temperature of the desulfurization slag and the decomposition temperature of the small-particle limestone are combined, and the decomposition products CaO and C0 of the small-particle limestone are utilized 2 The method effectively inhibits the hardening of the desulfurization slag, avoids the damage of the later-stage desulfurization slag crushing and the like to the large-scale graphite precipitated in the desulfurization slag, solves the problem that the large-scale graphite in the agglomerated desulfurization slag cannot be extracted and utilized, improves the recovery quantity and recovery efficiency of the large-scale graphite in the desulfurization slag, and particularly realizes the in-situ extraction of the large-scale graphite from the molten iron pretreatment desulfurization slag.
Example 2
Before the stirring of molten iron pretreatment is finished, adding 5mm small-particle limestone into a ladle according to 0.5kg of ton iron, lifting a stirring head until the lower end surface of the stirring head is level with the liquid level of molten iron, and controlling the rotating speed of the stirring head to be 100r/min for continuous stirring for 3min.
And (5) slag skimming operation. And after the slag skimming is finished, the slag ladle is opened, and the slag ladle is lifted to a slag yard by a crane. Pouring the slag pot to spread the desulfurization slag on the ground for spraying. The sprayed desulfurization slag is put into a water tank by a forklift, and is continuously stirred by a bucket to break up large slag blocks. The graded flotation is used for further separating, drying and recycling the flake graphite to obtain large-scale graphite, wherein the proportion of the large-scale graphite with the particle size of more than 80 meshes is 35%. The rest of the description will not be repeated here with reference to embodiment 1.
Example 3
Before the stirring of molten iron pretreatment is finished, adding 8mm small-particle limestone into a ladle according to 0.6kg of ton iron, lifting a stirring head until the lower end surface of the stirring head is level with the liquid level of molten iron, and controlling the rotating speed of the stirring head to be 105r/min for continuous stirring for 3.5min.
And (5) slag skimming operation. And after the slag skimming is finished, the slag ladle is opened, and the slag ladle is lifted to a slag yard by a crane. Pouring the slag pot to spread the desulfurization slag on the ground for spraying. The sprayed desulfurization slag is put into a water tank by a forklift, and is continuously stirred by a bucket to break up large slag blocks. The graded flotation is used for further separating, drying and recycling the flake graphite to obtain large-scale graphite, wherein the proportion of the large-scale graphite with the particle size of more than 80 meshes is 38%. The rest of the description will not be repeated here with reference to embodiment 1.
Example 4
Before the stirring of molten iron pretreatment is finished, adding 10mm small-particle limestone into a ladle according to 0.7kg of ton iron, lifting a stirring head until the lower end surface of the stirring head is level with the liquid level of molten iron, and controlling the rotating speed of the stirring head to be 110r/min for continuous stirring for 4min.
And (5) slag skimming operation. And after the slag skimming is finished, the slag ladle is opened, and the slag ladle is lifted to a slag yard by a crane. Pouring the slag pot to spread the desulfurization slag on the ground for spraying. The sprayed desulfurization slag is put into a water tank by a forklift, and is continuously stirred by a bucket to break up large slag blocks. The graded flotation is used for further separating, drying and recycling the flake graphite to obtain large-scale graphite, wherein the proportion of the large-scale graphite with the particle size of more than 80 meshes is 40%. The rest of the description will not be repeated here with reference to embodiment 1.
The foregoing has been described in what is considered to be the preferred embodiments of the invention, and the description of specific examples is only intended to provide a better understanding of the principles of the invention. It will be apparent to those skilled in the art that modifications and equivalents may be made in accordance with the principles of the invention, and such modifications and equivalents are considered to fall within the scope of the invention.
Claims (5)
1. The method for in-situ extraction of large-scale graphite from molten iron pretreatment desulfurization slag is characterized by comprising the following steps of calculating and adding desulfurizing agent according to the initial sulfur content of molten iron and desulfurization target requirements according to a normal KR pretreatment process, stirring by using a stirring head according to determined stirring time,
1) Before stirring, adding small-particle limestone into the ladle according to 0.5-0.7 kg of ton iron;
2) Lifting the stirring head until the lower end surface of the stirring head is level with the liquid level of the molten iron, and continuing stirring to uniformly mix the small-particle limestone in the iron slag;
3) After stirring, normal slag skimming operation is carried out according to the desulfurization process requirement, and after slag skimming is finished, the slag ladle is opened, and the slag ladle is transported to a slag field;
4) Pouring the slag pot to spread the desulfurization slag on the ground, and spraying with water;
5) Loading the sprayed desulfurization slag into a water tank by using a forklift, and continuously stirring and crushing a large slag block by using a bucket;
the small-particle limestone added in the later pretreatment stage in the step 4) is uniformly mixed in the iron slag after being stirred by a stirring head at a higher temperature, the temperature is suitable for the calcination and decomposition of the limestone, and the limestone is continuously decomposed in a slag pot after slag skimming to be decomposed into CaO and CO 2 Continuous decomposition of limestone and CO 2 Continuous discharge, effectively inhibits the agglomeration of iron slag, and further inhibits the hardening of the iron slag due to the pulverization of decomposed CaO when meeting water after spraying in a slag field;
and 5) the CaO obtained after limestone decomposition in the step is pulverized by water, so that good conditions are created for floating up graphite precipitated in the desulfurization slag in a water pool, flake graphite with different sizes floats in water, and then grading floatation is carried out, so that the original size of graphite flakes is protected, and the in-situ large-flake graphite is recovered in time.
2. The method for in-situ extraction of large scale graphite from molten iron pretreatment desulfurization slag as claimed in claim 1, wherein the adding mode in the step 1) can adopt automatic feeding in a bin or manual feeding, and the automatic feeding in the bin needs to be weighed in advance for standby and manually thrown in advance.
3. The method for in-situ extraction of large scale graphite from molten iron pretreatment desulfurization slag as claimed in claim 1, wherein the step 1) of stone small particle limestone has a particle size of 5 to 10mm.
4. The method for in-situ extraction of large scale graphite from molten iron pretreatment desulfurization slag as claimed in claim 1, wherein the rotational speed of the stirring head in the step 2) is controlled to be 100-110 r/min, and the stirring time is controlled to be 3-4 min.
5. The method for in-situ extraction of large scale graphite from molten iron pretreatment desulfurization slag as claimed in claim 1, wherein said step 3) is completed by lifting the slag pot to the slag yard by a crane.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104651554A (en) * | 2015-03-17 | 2015-05-27 | 马鞍山市华东冶金科技发展有限公司 | Method for cracking and granulating steel slag |
| CN104907171A (en) * | 2015-06-09 | 2015-09-16 | 安徽工业大学 | Method for recycling crystalline flake graphite from molten iron desulphurization residues |
| CN212894811U (en) * | 2020-07-22 | 2021-04-06 | 山东钢铁股份有限公司 | Device for promoting flake graphite precipitation in molten iron desulphurization process |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104651554A (en) * | 2015-03-17 | 2015-05-27 | 马鞍山市华东冶金科技发展有限公司 | Method for cracking and granulating steel slag |
| CN104907171A (en) * | 2015-06-09 | 2015-09-16 | 安徽工业大学 | Method for recycling crystalline flake graphite from molten iron desulphurization residues |
| CN212894811U (en) * | 2020-07-22 | 2021-04-06 | 山东钢铁股份有限公司 | Device for promoting flake graphite precipitation in molten iron desulphurization process |
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