CN115321534A - Method for in-situ extraction of large flake graphite from molten iron pretreatment desulphurization slag - Google Patents
Method for in-situ extraction of large flake graphite from molten iron pretreatment desulphurization slag Download PDFInfo
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- 239000002893 slag Substances 0.000 title claims abstract description 168
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 133
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 75
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 73
- 239000010439 graphite Substances 0.000 title claims abstract description 73
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 66
- 238000000034 method Methods 0.000 title claims abstract description 43
- 238000011065 in-situ storage Methods 0.000 title claims abstract description 24
- 238000000605 extraction Methods 0.000 title claims abstract description 11
- 238000003756 stirring Methods 0.000 claims abstract description 72
- 235000019738 Limestone Nutrition 0.000 claims abstract description 37
- 239000006028 limestone Substances 0.000 claims abstract description 37
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 32
- 230000023556 desulfurization Effects 0.000 claims abstract description 29
- 239000002245 particle Substances 0.000 claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 24
- 230000008569 process Effects 0.000 claims abstract description 21
- 238000011084 recovery Methods 0.000 claims abstract description 19
- 239000007788 liquid Substances 0.000 claims abstract description 7
- 238000005507 spraying Methods 0.000 claims abstract description 7
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims abstract description 4
- 235000011941 Tilia x europaea Nutrition 0.000 claims abstract description 4
- 239000004571 lime Substances 0.000 claims abstract description 4
- 238000007599 discharging Methods 0.000 claims abstract description 3
- 238000000354 decomposition reaction Methods 0.000 claims description 19
- 238000005188 flotation Methods 0.000 claims description 9
- 238000007667 floating Methods 0.000 claims description 6
- 239000011593 sulfur Substances 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- 238000001354 calcination Methods 0.000 claims description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 3
- 239000004575 stone Substances 0.000 claims description 2
- 230000008901 benefit Effects 0.000 abstract description 4
- 238000007885 magnetic separation Methods 0.000 abstract description 4
- 229910000831 Steel Inorganic materials 0.000 description 6
- 239000012071 phase Substances 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 238000005054 agglomeration Methods 0.000 description 4
- 230000002776 aggregation Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 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
- 238000005516 engineering process 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
- 230000001737 promoting effect Effects 0.000 description 2
- 238000003860 storage 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
- 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
- 239000003795 chemical substances by application Substances 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
- 230000003009 desulfurizing effect Effects 0.000 description 1
- 238000010586 diagram Methods 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
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- 239000011707 mineral Substances 0.000 description 1
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- 230000000704 physical effect Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
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- 238000004064 recycling Methods 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
- 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
- 238000005406 washing Methods 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
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- 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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Abstract
The invention discloses a method for extracting large-scale graphite from molten iron pretreatment desulphurization slag in situ, which comprises the following steps of 1) adding small-particle lime into a ladle according to 0.5-0.7 kg of iron per ton before stirring, wherein a desulfurizer is added according to a KR pretreatment process and stirred according to determined stirring time; 2) Lifting the stirring head until the lower end surface of the stirring head is flush with the liquid level of molten iron, and continuing stirring to uniformly mix the small-particle limestone in the iron slag; 3) After stirring, carrying out normal slag skimming operation according to the desulfurization process requirement, and after skimming is finished, discharging a slag ladle and conveying the slag ladle to a slag yard; 4) Dumping the slag tank to spread the desulfurized slag on the ground, and spraying with water; 5) The sprayed desulfurized slag is loaded into a pool by a forklift, and a bucket is used for continuously stirring and crushing large slag blocks. The method avoids the damage of the traditional crushing, magnetic separation and other processes to the scale, realizes the in-situ extraction and recovery of the large scale graphite, improves the recovery amount 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 recovering graphite in molten iron pretreatment desulphurization slag, and particularly relates to a method for extracting large-scale graphite in situ from molten iron pretreatment desulphurization 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 pay attention to the hot metal pretreatment process to carry out the pre-desulfurization treatment on the hot metal. At present, the domestic molten iron pretreatment desulfurization process mainly adopts two modes, namely a blowing method and a KR stirring method, wherein the KR stirring method has the advantages of high desulfurization efficiency, low consumption of desulfurizing agents and refractory materials, small molten iron temperature drop, low cost and the like, and is accepted by most iron and steel enterprises.
The steel-making desulphurization slag is waste slag generated in the process of carrying out pre-desulphurization treatment on molten iron before the molten iron enters a converter. Compared with converter slag and blast furnace slag, the recycling of KR desulfurization slag in China at present lacks attention, 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 level of resource utilization is not high, meanwhile, research on relevant physicochemical properties of desulfurization slag in China is relatively less, and the targeted resource utilization of desulfurization slag is influenced.
The main components of KR desulfurization slag are CaO and SiO 2 、Fe、CaF 2 、Al 2 O 3 MgO, caS, etc.; based on the reason of ore composition, KR desulfurization slag of partial metallurgical enterprises also contains partial TiO 2 And V 2 O 5 Etc., caO content even exceeding 50% by mass, caO/SiO 2 The mass ratio is about 3.5, the mass fraction of CaS is 1.0-2.5%, and part of metal particles brought in slag are also included. The mineral composition of the desulfurized slag mainly comprises a calcium aluminosilicate phase, a calcium silicate phase, a spinel compound phase, a metallic iron phase and a CaS phase, and the main phase of the high-temperature (1673-2073K) desulfurized slag is Ca 3 SiO 5 CaS and liquid phase, during cooling, due to Ca 3 SiO 5 Stable and easily decomposed 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 expands, and KR desulfurization slag is pulverized in the cooling process.
In the processes of tapping of a blast furnace, transferring of molten iron and KR pretreatment of the molten iron, because of the supersaturation of carbon elements in the molten iron caused by the change of the temperature thermal history of the molten iron and relevant physical kinetic energy conditions, aggregated crystalline flake graphite with different proportions is precipitated, and the graphite has the same performance as natural graphite after purification and even has better service performance than the natural graphite in certain specific fields. The value of the graphite is reflected in the size of the graphite flake, and the larger the flake is, the lower the friction coefficient is, the better the floatability, lubricity, plasticity and other performances are, and the higher the value is. In the production of flake graphite, large flake graphite can only be extracted from raw ores, the large flake graphite cannot be produced and synthesized by modern industrial technology, and the flake cannot be recovered once being damaged.
By analyzing the precipitation conditions of the large-scale graphite in the desulfurization slag and the components and properties of the desulfurization slag, the desulfurization process is optimized, the large-scale graphite in the desulfurization slag is protectively separated and extracted in situ, the emerging sources of the large-scale graphite are expanded, and the method has obvious economic value and strategic significance.
However, in the prior art, the carbon in the molten iron is saturated and precipitated to form scale graphite with different sizes, and the stirring of the stirring head accelerates the precipitation and floating of the graphite in the KR pretreatment process, so that the graphite is mixed in the desulfurized slag and enters the slag basin through slag skimming. Because of the physical properties of the desulphurization slag and the metal brought by stirring and slag skimming, the desulphurization slag is easy to agglomerate, and the recovery amount and the recovery efficiency of the scale graphite in the slag are seriously influenced.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a method for in-situ extracting large scale graphite from molten iron pretreatment desulphurization slag. According to the composition and characteristic research of the desulfurization slag, the small-particle limestone is added at the later stage of KR pretreatment for modification of the desulfurization slag, the desulfurization slag is poured into a slag field for spray cooling and decomposition reaction of the small-particle limestone, then the desulfurization slag enters a water tank for washing, and after the crystalline flake graphite floats upwards, the crystalline flake graphite enters a flotation process for recovery of the crystalline flake graphite. The method avoids the damage of the traditional crushing, magnetic separation and other processes to the scale in the prior art, realizes the in-situ extraction and recovery of the large scale graphite, improves the recovery amount and recovery efficiency of the scale graphite in the slag, and has very remarkable economic benefit.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a method for in-situ extracting large scale graphite from molten iron pretreatment desulphurization slag comprises the following steps of calculating and adding a desulfurizer according to the initial sulfur content of molten iron and desulphurization 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 lime into the ladle according to 0.5-0.7 kg of iron per ton;
2) Lifting the stirring head until the lower end surface of the stirring head is flush with the liquid level of molten iron, and continuing stirring to uniformly mix the small-particle limestone in the iron slag;
3) After stirring, carrying out normal slag skimming operation according to the desulfurization process requirement, and after skimming is finished, discharging a slag ladle and conveying the slag ladle to a slag yard;
4) Dumping the slag tank to spread the desulfurized slag on the ground, and spraying with water;
5) The sprayed desulfurized slag is loaded into a pool by a forklift, and a bucket is used for continuously stirring and crushing large slag blocks.
The adding mode in the step 1) can adopt automatic feeding of a bin or manual feeding, and the automatic feeding of the bin needs to be weighed in advance for standby and needs to be prepared in advance when thrown manually.
The granularity of the stone small particle limestone in the step 1) is required to be 5-10 mm.
The rotating 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) after the slag skimming in the step 3), hoisting the slag pot to a slag yard by a travelling crane.
Stirring the small-particle limestone added at the later stage of the pretreatment in the step 4) at a higher temperature by a stirring head, uniformly mixing the limestone in the iron slag, calcining and decomposing the limestone at a proper temperature, removing the slag, continuously decomposing the limestone in a slag pot, and decomposing the limestone into CaO and C0 2 Continuous decomposition of limestone, C0 2 And the slag field is sprayed, and decomposed CaO is pulverized when meeting water, so that the hardening of the iron slag is further inhibited.
And 5) pulverizing CaO obtained after the limestone decomposition in the step 5) in the presence of water, creating a good condition for floating graphite separated from the desulfurization slag in a water tank, floating flake graphite with different sizes in water, and then carrying out graded flotation to protect the original size of the graphite flakes and realize timely recovery of the in-situ large flake graphite.
The invention has the beneficial effects that:
1. according to the invention, small-particle limestone is added at the later stage of KR pretreatment for modifying desulfurization slag, is poured into a slag field for spray cooling and decomposition reaction of the small-particle limestone, and then is washed in a water tank, and the flake graphite floats upwards and then enters a flotation process for recovering the flake graphite, so that the damage of the traditional crushing, magnetic separation and other processes to the flake is avoided, the in-situ extraction and recovery of large-flake graphite are realized, the recovery amount and recovery efficiency of the flake graphite in the slag are improved, and the economic benefit is very obvious.
2. The invention combines the temperature of the desulfurized slag and the small-particle limestoneBy using decomposition products CaO and C0 of small-particle limestone 2 The method effectively inhibits the hardening of the desulphurization slag, avoids the damage of the desulphurization slag on the large-scale graphite separated out from the desulphurization slag in the later period, and the like, solves the problem that the large-scale graphite in the caking desulphurization slag can not be extracted and utilized, improves the recovery amount and the recovery efficiency of the large-scale graphite in the desulphurization slag, and improves the efficiency of extracting the large-scale graphite in situ from the molten iron pretreatment desulphurization slag.
3. The invention spreads the desulphurization slag on the ground by dumping the slag tank and sprays the desulphurization slag by water.
At the moment, the desulfurization slag has higher temperature, is beneficial to promoting the decomposition of limestone, and has small granularity, large reaction interface and quick reaction. The small-particle limestone added in the later stage of pretreatment is uniformly mixed in the iron slag after being stirred by a stirring head, and the temperature is suitable for the calcination decomposition of the limestone. After slag skimming, the slag is continuously decomposed in a slag pot into CaO and C0 2 Due to continued decomposition, C0 2 The continuous discharge effectively inhibits the agglomeration of the iron slag, and the decomposed CaO is pulverized when meeting water after the slag yard is sprayed, so the agglomeration of the iron slag is further inhibited.
4. The sprayed desulfurization slag is loaded into a water tank, and a bucket continuously stirs and crushes large slag blocks. Decomposed C0 due to decomposition of the early stage small particle limestone 2 The decomposed CaO is atomized when meeting water, so that good conditions are created for floating graphite separated from the desulfurization slag in a water tank, the scale graphite with different sizes floats in water, and then the grading flotation is carried out, so that the original size of the graphite scale is protected to the maximum extent, and the in-situ large scale graphite is recovered in time.
Drawings
FIG. 1 is a schematic process flow diagram of an embodiment of the present invention.
Detailed Description
In order to make those skilled in the art better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Example 1
With reference to fig. 1, a method for extracting large scale graphite from molten iron pretreatment desulphurization slag in situ, according to a normal KR pretreatment process flow, according to the initial sulfur content of molten iron and desulphurization target requirements, calculating the addition amount of a desulfurizer and determining the addition amount, stirring at normal rotating speed of a stirring head, and determining the stirring time, comprises the following steps:
1. before stirring, adding small-particle lime into a ladle according to 0.5-0.7 kg of iron per ton, wherein the particle size of the small-particle lime stone 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 application and needs to be prepared in advance when thrown manually.
2. And lifting the stirring head until the lower end surface of the stirring head is flush 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 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 is finished, carrying out normal slagging-off operation according to the desulfurization process requirement. And after the slag is removed, the slag ladle car is driven out, and the slag ladle is transported to a slag field through a crane and the like.
4. And (4) pouring the slag tank, flatly paving the desulfurized slag on the ground, and spraying with water.
At the moment, the desulfuration residue has higher temperature, which is beneficial to promoting the decomposition of limestone, the decomposition is fastest when the temperature is 1000-1300 ℃, and the granularity is smaller, the reaction interface is larger, and the reaction is quicker. The small-particle limestone added in the later stage of pretreatment is uniformly mixed in the iron slag after being stirred by a stirring head, and the temperature is suitable for the calcination decomposition of the limestone. Continuously decomposing the slag into CaO and C0 in the slag pot after slagging off 2 Due to continued decomposition, C0 2 The continuous discharge effectively inhibits the agglomeration of the iron slag, and the decomposed CaO is pulverized when meeting water after the slag yard is sprayed, so the agglomeration of the iron slag is further inhibited.
5. The sprayed desulfurized slag is loaded into a pool by a forklift, and a bucket is used for continuously stirring and crushing large slag blocks.
Decomposed C0 due to decomposition of the early stage small particle limestone 2 The decomposed CaO is atomized when meeting water, so that good conditions are created for floating graphite separated from the desulfurization slag in a water tank, the scale graphite with different sizes floats in water, and then the grading flotation is carried out, so that the original size of the graphite scale is protected to the maximum extent, and the in-situ large scale graphite is recovered in time.
In this case, the temperature of the desulfurized slag and the decomposition temperature of the small limestone particles are combined, and the decomposition products CaO and C0 of the small limestone particles are used 2 The method effectively inhibits the hardening of the desulphurization slag, avoids the damage of the desulphurization slag on the large-scale graphite separated out from the desulphurization slag in the later period, solves the problem that the large-scale graphite in the caking desulphurization slag can not be extracted and utilized, improves the recovery amount and the recovery efficiency of the large-scale graphite in the desulphurization slag, and particularly realizes the in-situ extraction of the large-scale graphite from the molten iron pretreatment desulphurization slag.
Example 2
Before the pretreatment and stirring of the molten iron are finished, 0.5kg of iron per ton is added into the ladle by 5mm small-particle limestone, the stirring head is lifted until the lower end surface of the stirring head is flush with the liquid level of the molten iron, the stirring head is controlled to rotate at a speed of 100r/min for continuous stirring, and the stirring time is 3min.
And (4) slag skimming operation. And after the slag skimming is finished, the slag tank truck is driven out, and the slag tank is hoisted to a slag yard by a travelling crane. And pouring the slag tank to spread the desulfurized slag on the ground for spraying. The sprayed desulfurized slag is loaded into a pool by a forklift, and a bucket is used for continuously stirring and crushing large slag blocks. And (3) further separating, drying and recovering the flake graphite by using classified flotation to obtain large flake graphite, wherein the proportion of the large flake graphite with the granularity of more than 80 meshes is 35%. The rest refer to embodiment 1, and are not described herein again.
Example 3
Before the pretreatment and stirring of the molten iron are finished, 0.6kg of small-particle limestone with the size of 8mm is added into the ladle according to the ton of the molten iron, the stirring head is lifted until the lower end face of the stirring head is flush with the liquid level of the molten iron, the stirring head is controlled to rotate at the speed of 105r/min for continuous stirring, and the stirring time is 3.5min.
And (5) slag skimming operation. And after the slag skimming is finished, the slag tank truck is driven out, and the slag tank is hoisted to a slag yard by a travelling crane. And the desulfuration slag is spread on the ground for spraying by dumping the slag tank. The sprayed desulfurized slag is loaded into a pool by a forklift, and a bucket is used for continuously stirring and crushing large slag blocks. And (3) further separating, drying and recovering the flake graphite by using classified flotation to obtain large flake graphite, wherein the proportion of the large flake graphite with the granularity of more than 80 meshes is 38%. The rest refer to embodiment 1, and are not described herein again.
Example 4
Before the pretreatment and stirring of the molten iron are finished, 0.7kg of small 10mm limestone is added into a ladle according to ton of iron, a stirring head is lifted until the lower end face of the stirring head is flush with the liquid level of the molten iron, the stirring head is controlled to rotate at a speed of 110r/min for continuous stirring, and the stirring time is 4min.
And (5) slag skimming operation. And after the slag skimming is finished, the slag tank truck is driven out, and the slag tank is hoisted to a slag yard by a travelling crane. And the desulfuration slag is spread on the ground for spraying by dumping the slag tank. The sprayed desulfurized slag is loaded into a pool by a forklift, and a bucket is used for continuously stirring and crushing large slag blocks. And (3) further separating, drying and recovering the flake graphite by using classified flotation to obtain large flake graphite, wherein the proportion of the large flake graphite with the granularity of more than 80 meshes is 40%. The rest refer to embodiment 1, and are not described herein again.
The above description is of the preferred embodiment of the present invention, and the description of the specific embodiment is only for better understanding of the idea of the present invention. It will be appreciated by those skilled in the art that various modifications and equivalents may be made in accordance with the principles of the invention and are considered to be within the scope of the invention.
Claims (7)
1. A method for in-situ extracting large scale graphite from molten iron pretreatment desulphurization slag comprises the following steps of calculating and adding a desulfurizer according to the initial sulfur content of molten iron and desulphurization target requirements according to a normal KR pretreatment process, and stirring by using a 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 iron per ton;
2) Lifting the stirring head until the lower end surface of the stirring head is flush 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, carrying out normal slag skimming operation according to the desulfurization process requirement, and after skimming is finished, discharging a slag ladle and conveying the slag ladle to a slag yard;
4) Dumping the slag tank to spread the desulfurized slag on the ground, and spraying with water;
5) The sprayed desulfurized slag is loaded into a pool by a forklift, and a bucket is used for continuously stirring and crushing large slag blocks.
2. The method for in-situ extraction of large-scale graphite from molten iron pretreatment desulphurization slag according to claim 1, wherein the step 1) is carried out by automatic bunker feeding or manual feeding, and the automatic bunker feeding needs to be weighed for later use in advance and needs to be prepared in advance when thrown manually.
3. The method for in-situ extraction of large scale graphite from molten iron pretreatment desulfurization slag as claimed in claim 1, wherein the particle size of the small stone particle limestone of step 1) is required to be 5-10 mm.
4. The method for in-situ extraction of large-scale graphite from molten iron pretreatment desulphurization slag according to claim 1, wherein the rotation speed of the stirring head in the step 2) is controlled at 100-110 r/min, and the stirring time is controlled at 3-4 min.
5. The method for extracting large scale graphite from molten iron pretreatment desulphurization slag in situ according to claim 1, wherein the step 3) skimming is completed by lifting a slag pot to a slag yard through a travelling crane.
6. The method for in-situ extraction of large-scale graphite from molten iron pretreatment desulphurization slag as claimed in claim 1, wherein the small-grained limestone added at the later stage of the pretreatment of step 4) is stirred by a stirring head at a higher temperature and then uniformly mixed in the iron slag, and the temperature is suitable for the calcination decomposition of the limestone, the slagging-off is carried outThen continuously decomposing the slag into CaO and C0 2 Continuous decomposition of limestone, C0 2 And the slag is continuously discharged, the caking of the iron slag is effectively inhibited, and the decomposed CaO is pulverized when meeting water after the slag yard is sprayed, so that the caking of the iron slag is further inhibited.
7. The method for in-situ extraction of large-scale graphite from molten iron pretreated desulphurization slag as claimed in claim 1, wherein CaO obtained after decomposition of limestone in step 5) is pulverized in water to create good conditions for floating graphite precipitated from the desulphurization slag in a water pool, and the large-scale graphite floats in water in different sizes, and then is subjected to graded flotation to protect the original size of graphite flakes, thereby realizing timely recovery of the in-situ large-scale graphite.
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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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