CN113549807A - Method for smelting molten nickel iron with low cost and high yield - Google Patents
Method for smelting molten nickel iron with low cost and high yield Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C33/00—Making ferrous alloys
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- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/02—Roasting processes
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- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B23/00—Obtaining nickel or cobalt
- C22B23/02—Obtaining nickel or cobalt by dry processes
- C22B23/023—Obtaining nickel or cobalt by dry processes with formation of ferro-nickel or ferro-cobalt
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- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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Abstract
The invention discloses a method for smelting molten nickel iron with low cost and high yield, and relates to the technical field of ferrous metallurgy. The method comprises the following steps: s1 crushing and mixing: crushing, screening, mixing and stirring large blocks of laterite-nickel ore stones to uniformly mix the large blocks of laterite-nickel ore stones; s2 drying: drying the raw ore in the step S1 by using a drying kiln to control the moisture of the raw ore to be 23-26%; s3, batching: the raw ore is proportioned to meet the following requirements: the furnace grade is 1.45-1.64%, the iron TFe is 18.5-20%, the Si/Mg ratio is 1.50-1.55, and the slag alkalinity R is 0.65; s4 calcination: calcining the raw material proportioned in the step S3 in a rotary kiln to obtain clinker, so as to obtain red hot calcine; s5 smelting: and smelting and roasting in a submerged arc furnace to obtain the qualified ferronickel aquatic product. The method of the invention can ensure the life safety of the refractory material, expand the productivity, improve the production efficiency and comprehensively control the production cost.
Description
Technical Field
The invention relates to the technical field of ferrous metallurgy, in particular to a method for smelting molten nickel iron with low cost and high yield.
Background
Nickel is an important strategic metal, and has become a key material in industries such as modern aviation, national defense and the like because of good ductility, strong toughness, good high-temperature performance and oxidation and corrosion resistance. The method is widely applied to a plurality of fields of stainless steel, alloy steel, electroplating materials, batteries and the like. Among them, stainless steel is dominant in the consumption ratio of nickel, and accounts for about 68% of the consumption ratio of the global nickel.
The laterite-nickel ore has the advantages of abundant reserves, low mining difficulty and the like, and becomes the current main nickel production raw material along with the continuous progress of the treatment process. The laterite-nickel ore is divided into a limonite type (Ni: 0.8-1.5%; TFe: 40-52%), a transition type (Ni: 1.5-1.8%; TFe: 25-40%) and a sapropel type (Ni: 1.8-3.0%; TFe: 10-25%) according to the ore deposit profile from the ground surface to the bottom. In the process of smelting the nickel-based stainless steel, compared with the process of taking electrolytic nickel as a nickel source, the nickel-iron as the raw material can effectively avoid energy waste caused by high-temperature fusion after nickel and iron are separated, and is more reasonable and has more cost advantages to a certain extent. The pyrometallurgical treatment process of the laterite-nickel ore gradually becomes the mainstream production process of the laterite-nickel ore by virtue of the advantages of short flow, wide raw material application range, relatively mature process and the like.
However, in the prior art, in the process of smelting molten nickel iron by using laterite-nickel ore, the productivity cannot be further improved all the time due to the limitation of the equipment state and the production bottleneck, so that the production cost cannot be continuously reduced. The reasons for the existing situation mainly include the following:
1. the parameters of the transformer of the submerged arc furnace are unreasonable, so that the current power can only be 29500KVA at the highest, the load lifting is limited, and the further lifting of the capacity is restricted;
2. the electric parameters are unreasonable, the smelting molten pool shrinks, the fluctuation of furnace conditions is caused, and the fluctuation of the temperature of the smelting slag is large;
3. refractory materials of the submerged arc furnace body are corroded to different degrees, so that the maximization of the power improvement and the safe production are restricted;
4. the current similar process has low daily productivity, large heat loss in the production process and high smelting power consumption, thus leading to high manufacturing cost;
5. because of the instability of raw materials, the stability of smelting in the furnace is insufficient;
6. the coal feeding equipment of the rotary kiln is limited, and cannot meet the requirement of coal heat supply during the existing high-kiln-speed large-feeding, so that the feeding of the rotary kiln is insufficient, and the requirement of the ore-smelting furnace on the material can not be met;
7. when the rotary kiln realizes the large-kiln-speed large-batch production, the rotary kiln is restricted by insufficient air distribution quantity, and the oxygen requirement is insufficient, so that the phenomena of ring formation, coal leakage and the like can be caused when the pulverized coal cannot be fully combusted;
8. after the feeding amount of the rotary kiln is increased, the conditions of ring formation, coal leakage and the like occur due to the limitation of a coal feeder and the instability of the calcine temperature, so that the rhythm of the whole production line is influenced.
Therefore, a smelting process technical route which can ensure the service life safety of the refractory materials, can expand the productivity, improve the production efficiency and comprehensively control the production cost is sought, and the problem to be solved is urgently needed.
Disclosure of Invention
The invention provides a method for smelting molten nickel iron with low cost and high yield, and aims to solve the problems in the background art.
In order to achieve the technical purpose, the invention mainly adopts the following technical scheme:
a method for smelting nickel molten iron with low cost and high yield is characterized by comprising the following steps:
s1 crushing and mixing: crushing, screening, mixing and stirring large blocks of laterite-nickel ore stones to uniformly mix the large blocks of laterite-nickel ore stones;
s2 drying: drying the raw ore in the step S1 by using a drying kiln to control the moisture of the raw ore to be 23-26%; therefore, the sticky ores are reduced, the smoke output in the whole process is reduced, the loss of Ni content is reduced, and the calcining pressure and coal consumption of the rotary kiln are reduced. (the moisture of the dry ore can be adjusted according to the moisture of the raw ore, the weather condition, the on-site dry ore inventory and the characteristics of the ore).
S3, batching: the raw ore is proportioned to meet the following requirements: the furnace grade is 1.45-1.64%, the iron TFe is 18.5-20%, the Si/Mg ratio is 1.50-1.55, and the slag alkalinity R is 0.65;
s4 calcination: calcining the raw material proportioned in the step S3 in a rotary kiln to obtain clinker, so as to obtain red hot calcine;
s5 smelting: and smelting and roasting in a submerged arc furnace to obtain the qualified ferronickel aquatic product.
In the present invention, in the step S4, the calcination temperature of the calcine in the rotary kiln is 710-730 ℃. The firing temperature of the rotary kiln calcine is controlled to be reduced from original 730-phase 760 ℃ to current 710-phase 730 ℃, so that 3-valent iron in the calcine can be effectively promoted to be converted into 2-valent iron, the melting speed of furnace burden is increased, and the smelting power consumption is reduced; meanwhile, the ring-forming condition in the rotary kiln is reduced because the calcine temperature is reduced, and the coal consumption of the rotary kiln can also be reduced. In the actual production, the continuous production of the maximum production capacity of the rotary kiln with the batch size of 120 t/h is realized.
In the invention, in the step S4, the coal feeder of the rotary kiln workshop is a CWF-1200, 20 ton coal feeder, and the batch charge at the kiln speed is 900rpm/100 t.h-930 rpm/110 t.h.
Furthermore, a Roots blower is arranged at the kiln head of the rotary kiln, an air outlet of the Roots blower is blown into the rotary kiln from three channels divided by the kiln head cover, and the air flow direction is horizontal to the central line of the rotary kiln.
Furthermore, the wind pressure of the Roots blower is 49Kpa, and the wind volume is 79.4m3/min。
In the invention, in the step S4, the output rate of the calcine is more than or equal to 68.5%; the tail ash discharge amount is less than or equal to 6 percent; the carbon content of the tail ash is less than or equal to 1.5 percent.
As a further improvement of the invention, in the step S5, the moisture content of the coal in the ore smelting furnace is less than or equal to 7 percent, and the weight percentage of the small-charge coke pieces to the medium-charge coke pieces is 20-33: 80-67, wherein the particle size of the small material coke dices is 5-20mm, and the particle size of the medium material coke dices is 10-35 mm. In the actual production, the consumption of the nut coke is effectively reduced by about 7.8 percent. Meanwhile, on the premise of low silicon-magnesium ratio, the AL in the furnace is reasonably controlled2O3The content and the FeO content of the furnace slag are 10.5-11.5%, the melting point of the slag mold is effectively controlled, the slagging temperature of furnace burden can be reduced, the slag temperature is further reasonably controlled, the fluidity of the furnace slag is improved, the problem of difficult slag-iron separation is avoided, and the NiO content of the furnace slag can be stably controlled to be 0.045-0.055%.
Preferably, in the step S5, the clearance height from the core material level to the furnace cover in the submerged arc furnace is 400-500mm, and the clearance height from the peripheral material level to the furnace cover is 2.0-2.1m, so as to effectively ensure the service life of the refractory material of the furnace lining at the periphery.
Further, in step S5, the transformer of the submerged arc furnace is 13000KVA, the operation voltage level is 17-20 levels, the voltage is 483-443V, the power is 31000-33000KWH, and the current is 43000A.
In the invention, the slag FeO after smelting is 10.5-11.5%, and NiO is 0.045-0.055%; and the molten iron Ni is 10.5-11.5%.
Compared with the prior art, the invention has the following beneficial effects:
(1) establishing a slag type control principle that FeO in slag is controlled to be 10.5-11.5% by implementing a submerged arc furnace production process of 'low nickel and iron distribution, low silicon-magnesium ratio and high aluminum'; on the premise that the silicon-magnesium ratio of the slag is about 1.5-1.55, the temperature of the slag is accurately controlled at 1550-1555 ℃, the fluidity of the slag is ensured, and meanwhile NiO in the slag is ensured to be in a proper range; slag adhering of the furnace body is effectively realized, refractory materials of the furnace lining of the submerged arc furnace are effectively ensured, and the depth of iron holes of the four submerged arc furnaces is ensured to be 1.2-1.6 m;
(2) through the stable operation of high power, the material melting amount of the furnace can be effectively improved, the consumption of 9000-9500t dry ores of 4 furnaces can be guaranteed, and the productivity is greatly improved.
(3) By adjusting the control of FeO and other elements influencing the melting point in the slag to enter the furnace, the melting temperature of the furnace burden is reduced by 20-30 ℃, and 2300-2400 tons of dry ore consumed per day by a single ore-smelting furnace are ensured; the Ni point in the molten iron is increased to 10.5-11.5%, the daily total nickel point of the submerged arc furnace is increased from 7500 to 8500, the total nickel content is effectively increased, and the power consumption of the smelting nickel point of the submerged arc furnace is reduced from 357 to 340 ℃;
(4) by properly reducing the slag line (1.4m) and improving the height of the charge level (clearance 400mm away from a furnace cover), the actual thickness of a charge layer is increased by 600mm compared with the original thickness, most of red-hot electrodes are surrounded by the charge layer, the oxidation of the electrodes is reduced, the electrode roasting efficiency is improved, the problems of fast material centralization of a furnace core after the power is improved and the like are solved, the problems of material collapse, hole blockage positive pressure slag turning, frequent material wrapping and the like in the slag discharging process are reduced, the smelting current of the submerged arc furnace is stable, and the power factor is as high as 0.99; in the production process of the furnace, the problem of fire channeling and smoke generation of the furnace cover is effectively inhibited, clean production is ensured, and the environmental protection problem in the aspect is solved; the operation rate of the submerged arc furnace is effectively improved, the furnace cover temperature is reduced by more than 100 ℃ from 800 ℃ to 700 ℃, the heat loss is reduced, and the energy-saving production is realized;
(5) the higher FeO control and the control of the particle size ratio of the coke briquette integrally reduce the using amount of the coke briquette, about 8 percent, save the cost of raw materials, ensure the stable control of the components of the smelting of the submerged arc furnace, stabilize the FeO of the furnace slag, stabilize the temperature of the slag and finally keep the stability of the furnace condition;
(6) the reasonable and strict control of the calcine temperature can effectively control the potential safety hazard of ring formation of the rotary kiln;
(7) the utilization rate of the coal dust is improved, the carbon content of the tail ash is reduced by less than 1.5 percent from 2.2 percent before the process is implemented, and the phenomenon of coal leakage is effectively solved; the output rate of the calcine is more than or equal to 68.5 percent, and is improved by 2 percent; the tail ash discharge amount is reduced to below 6 percent from about 8.0 percent;
(8) the operation rate of the rotary kiln is improved to 95.85 percent, which is 16.80 percent higher than that of the prior project;
(9) the corresponding bituminous coal consumption is not increased after the yield is improved, and the dry ore coal consumption is kept to be 78Kg, even slightly reduced.
Detailed Description
In order to make the technical solutions of the present invention more clear and definite for those skilled in the art, the present invention is further described in detail with reference to the following examples, but the embodiments of the present invention are not limited thereto.
Examples
A method for smelting molten nickel iron with low cost and high yield comprises the following steps:
s1 crushing and mixing: drying the laterite-nickel ore with high moisture in an open-air stock ground, and reducing the moisture of the raw ore before entering the working procedure as much as possible; then transferring the laterite nickel ore to a raw material greenhouse according to the production rhythm, and crushing, screening, mixing and stirring the laterite nickel ore stone to uniformly mix the laterite nickel ore stone;
s2 drying: drying the raw ore in the step S1 by using a drying kiln to control the moisture of the raw ore to be 23-26%; therefore, the sticky ores are reduced, the smoke output in the whole process is reduced, the loss of Ni content is reduced, and the calcining pressure and coal consumption of the rotary kiln are reduced. (the moisture of the dry ore can be adjusted according to the moisture of the raw ore, the weather condition, the on-site dry ore inventory and the characteristics of the ore).
S3, batching: the raw ore is proportioned to meet the following requirements: the furnace grade is 1.45-1.64%, the iron TFe is 18.5-20%, the Si/Mg ratio is 1.50-1.55, and the slag alkalinity R is 0.65;
s4 calcination: calcining the raw material proportioned in the step S3 in a rotary kiln to obtain clinker, so as to obtain red hot calcine; wherein the sintering temperature of the calcine in the rotary kiln is 710-730 ℃.
The coal feeder of the rotary kiln workshop is a CWF-1200, 20-ton coal feeder, and the feeding amount of the kiln is 900rpm/100 t.h-930 rpm/110 t.h.
Furthermore, a Roots blower is arranged at the kiln head of the rotary kiln, an air outlet of the Roots blower is blown into the rotary kiln from three channels divided by the kiln head cover, and the air flow direction is horizontal to the central line of the rotary kiln.
The wind pressure of the Roots blower is 49Kpa, and the wind volume is 79.4m3/min。
The output rate of the calcine is more than or equal to 68.5 percent through the calcination of the rotary kiln; the tail ash discharge amount is less than or equal to 6 percent; the carbon content of the tail ash is less than or equal to 1.5 percent.
S5 smelting: and smelting and roasting in a submerged arc furnace to obtain the qualified ferronickel aquatic product. Wherein the water content of the coal in the ore-smelting furnace is less than or equal to 7 percent, and the weight percentage of the small-charge coke pieces to the medium-charge coke pieces is 20-33: 80-67, the particle size of the small material coke dices is 5-20mm, and the particle size of the medium material coke dices is 10-35 mm.
The clearance height from the material level of the furnace core in the ore-smelting furnace to the furnace cover is 400-500mm, and the clearance height from the peripheral material level to the furnace cover is 2.0-2.1 m.
The submerged arc furnace transformer is 13000KVA, the operation voltage level is 17-20, the voltage is 483-443V, the power is 31000-33000KWH, and the current is 43000A.
In the embodiment, the slag FeO after smelting is 10.5-11.5%, and NiO is 0.045-0.055%; and the molten iron Ni is 10.5-11.5%.
1. The invention determines technical parameters.
The power of the submerged arc furnace is increased to 33000KVA in the embodiment; the problem of limited operating current is solved; in the production process, the lower insertion depth of the electrode can be reasonably operated, so that the current is stable, the smoke of the furnace cover is less, and the high-power clean production is realized.
After the replacement, the upgrade and the improvement of the production process of the transformer of the submerged arc furnace, the material amount for the submerged arc furnace is obviously increased, and the production mode of the rotary kiln can not meet the current production requirement. In order to meet the production material of the submerged arc furnace, the rotary kiln workshop must accelerate the kiln speed and the production of the feeding amount (the design of the rotary kiln tooling: 100m 4.4m, the refractory material of the kiln is the later-stage kiln age, the material blocking ring in the kiln is lost, the material flowing speed in the kiln is high, the preheating time is short, and the reasonable feeding amount of the kiln is controlled at 800rpm/85 t.h). The material demand of the submerged arc furnace can be met by the rotary kiln at 800rpm/85 t.h before transformation.
In order to meet the requirement of high-power material use in a submerged arc furnace workshop, a rotary kiln workshop is used for replacing and upgrading a coal feeder system, and an SPF-10-ton coal feeder is replaced by a CWF-1200-ton coal feeder or a 20-ton coal feeder. The speed and the feeding amount of the kiln are increased from 800rpm/85 t.h to 900rpm/100 t.h, even 930rpm/110 t.h after the replacement and the upgrade. But the control indexes of the rotary kiln in the production process obviously fluctuate after the kiln speed and the material feeding amount are increased, such as: the kiln speed and the feeding amount are unstable, the temperature of the kiln is often increased slowly due to the low temperature of the material, and the actual yield is not as stable as the production yield at 800rpm/85 t.h; the frequent slow kiln temperature rise causes high coal consumption, the coal consumption reaches 86.39kg per ton dry ore on average when the coal consumption is the highest, 7.39kg per ton dry ore is higher than the specified index 79kg per ton dry ore (calculated according to 26 ten thousand tons of total dry ore per month, 1921.4 tons of coal are used for more than one month), and the coal consumption index of the rotary kiln seriously exceeds the standard; the coal consumption is high, the coal consumption is large, the rotary kiln generates the condition of coal leakage, tail ash is blackened, the carbon content of the tested tail ash reaches more than 2.2 percent of the average value, and the environmental pollution and the waste of coal powder are caused; after the kiln speed and the feed amount are increased, the use of the negative pressure of the rotary kiln is increased, the tail ash amount is increased due to the increase of the use amount of the negative pressure, the actual output capacity of the rotary kiln is reduced, the tail ash amount is increased to more than 8 percent, and the energy consumption is wasted; the ring formation in the kiln is caused by insufficient combustion of the pulverized coal, the kiln is often burnt to death, the production is seriously influenced, and the potential safety hazard of personnel operation is very large.
The original air distribution structure of the rotary kiln can cause the condition of 'kiln death' due to insufficient original air distribution amount when 100/105/110 tons of materials are calcined and fed.
When the 'dead kiln' condition occurs, the furnace needs to be stopped and cooled and then is manually driven out, so that serious energy waste is caused, the low-power operation of the submerged arc furnace affects the production yield, and the potential safety hazard of personnel operation also exists.
Aiming at solving the problem of insufficient production caused by insufficient air distribution after replacing the CWF-1200 of the novel coal feederNegative effects. The applicant adds a roots blower again at the kiln head, and the blower is selected as follows: selecting a Roots blower with model number of JAS250, boosting pressure to 49Kpa, and air volume of 79.4m3And/min, laying a pipeline, distributing three channels from a kiln head cover, and blowing the pipeline into the kiln, wherein the direction of air flow is horizontal to the central line of the rotary kiln. After the blower is installed, the kiln speed material amount and the air volume of the blower are adjusted, and the frequency (Hz) and the hourly air volume of the blower are respectively used when the kiln speed material amount is 850rpm/95 t.h, 900rpm/100 t.h, 900rpm/105 t.h and 930rpm/110 t.h. And recording the speed of each kiln, the feeding amount and the frequency of the blower by using a recording table after debugging, and implementing a standardized operation management mode of the rotary kiln. So as to achieve the stable high-yield low-consumption production of the rotary kiln and meet the requirement of high-power production materials of the submerged arc furnace.
The frequency and the blast volume of the feeding quantity of each kiln speed when the new roots blower is used in the production of the rotary kiln are shown in the following table 1.
TABLE 1 frequency and blast volume for each kiln speed
After the air distribution of the kiln head of the rotary kiln is realized, the problem of air shortage of the rotary kiln during high-kiln-speed large-feeding is basically solved, and the condition that the rotary kiln is dead in normal production is completely avoided. All indexes of the rotary kiln production are effectively controlled.
After the Roots blower is added, the change of index control of the rotary kiln is counted: the output rate of the calcine is more than or equal to 68.5 percent, and is improved by 2 percent; the tail ash discharge amount is reduced to about 6 percent from about 8.0 percent; the carbon content of the tail ash is reduced to below 1.5 percent from 2.2 percent, and the phenomenon of coal leakage is effectively controlled; the production stop of the kiln due to the fact that the air distribution is insufficient after the production is improved and the kiln is burnt out after the kiln skin is over is controlled, and production accidents are zero; the yield is improved from 8000 tons of dry ore per day to more than 9500 tons of dry ore per day, the yield of the dry ore per day is improved by more than 1500 tons, and the production requirement of the submerged arc furnace is met; the calcine temperature can be stably controlled; the corresponding bituminous coal consumption is not increased after the yield is improved, the dry ore coal consumption is kept to be 78Kg, even slightly reduced, and the burning rate of the calcine and the full combustion utilization rate of the coal dust are improved.
2. The invention determines the batching scheme.
The previous dosing schedule test of the present invention is shown in table 2 below.
Table 2: batching scheme
Wherein, the comprehensive factors required to be considered by the test formula are as follows: the main principles are that the types and the quantity of raw ore stocks and the components of produced molten iron can meet the requirements of the subsequent procedures, the cost of ore type matching is optimized, and the control difficulty of the smelting process is reduced.
According to the existing production conditions, through repeated production practices, the formula which is most suitable for the cost control and the equipment working condition at the current stage is selected and is shown in the following table 3: (in the production process, the smooth running condition of the production running through the whole production line is fully considered, the production of the scheme can be effectively matched with the front and back working procedures, the effective continuous production is ensured, and the expected effect can be achieved)
Table 3: optimal dosing scheme
| TNi | TFe | SiO2 | MgO | CaO | Al2O3 | S | P | Cr2O3 | Fe/Ni | Si/Mg | R |
| 1.47 | 19.93 | 33.24 | 21.31 | 0.25 | 2.45 | 0.01 | 0.004 | 1.38 | 13.51 | 1.56 | 0.61 |
Note: the balance of less than 100 percent is the mass percent of water in dry ore
3. Selecting smelting operation parameters and establishing process parameters.
a. The smelting operating parameters are shown in table 4 below.
Table 4: operating parameters of smelting
| Grade of operation | Operating voltage | Input power | Electric current |
| 17-20 stages | 483-443V | 31000-33000KWH | 43000A left and right |
b. The ratio and particle size of the small and medium coke breeze are shown in Table 5 below.
Table 5: ratio and granularity of small and medium coke
| Item | Particle size mm | In proportion% |
| Middle material diced coke | 10-35 | 20-33 |
| Small material diced coke | 5-20 | 80-67 |
Wherein, when 20 percent of the middle material coke is contained, the current is 38000A-39000A; slag temperature fluctuation interval: ± 20 ℃, dry ore consumption: 1900t to 2250t are shown in Table 6.
Table 6: the slag component when containing 20% of middle material coke
| TFe(％) | TNi(％) | CaO(％) | Al2O3(％) | Si/Mg | R | Temperature of slag |
| 10.5-12.5 | 0.06 | 1.95 | 3.5-4.0 | 1.55-1.65 | 0.64 | 1535-1555 |
When 20% of the middle material coke is contained, the current is 39000A to 40000A; slag temperature fluctuation interval: 10 ℃, dry ore consumption: 2100t to 2350t are specifically shown in Table 7.
Table 7: the composition of the slag when the slag contains 25% of middle material coke
| TFe(％) | TNi(％) | CaO(％) | Al2O3(％) | Si/Mg(％) | R | Temperature of slag |
| 10-11 | 0.045 | 1.95 | 3.6-4.2 | 1.5-1.55 | 0.64 | 1550-1560 |
When 33% of the middle material coke is contained, the current is 38000A-41000A; slag temperature fluctuation interval: ± 30 ℃, dry ore consumption: 1800t to 2000t, as shown in Table 8.
Table 8: the composition of the slag when the slag contains 33% of middle material coke
| TFe | TNi | CaO | Al2O3 | Si/Mg | R | Temperature of slag |
| 10.5-12 | 0.065 | 1.95 | 3.6-4.2 | 1.45-1.50 | 0.64 | 1540-1570 |
As can be seen from the data in tables 6 to 8, the ratio of the middle material coke dices is not too small or too large; too small, the stability of the ingredients is insufficient; too large will cause too much C accumulation in the furnace, thus causing deviation of the designed slag form, and increasing the difficulty of production operation, especially in electrode current, slag temperature control and material melting speed, therefore, by comparing the production of 20%, 25% and 33%, the final selected proportion is not 25% most suitable.
c. The final control results of the slag forms produced and prepared through the above steps using the optimal batching scheme (table 3) are shown in table 9 below.
Table 9: final slag form composition
| TFe(％) | TNi(％) | CaO(％) | Al2O3(％) | Si/Mg | R | Temperature of slag |
| 10.5-11.5 | 0.045-0.055 | 1.95 | 3.5-4.0 | 1.5-1.55 | 0.64 | 1545-1560 |
d. The molten iron produced through the above-described processes using the optimum formulation (table 3) has the following composition as shown in table 10 below.
Table 10: final molten iron composition
| Ni(％) | Cr(％) | Si(％) | S(％) | P(％) | C(％) | Iron temperature DEG C |
| 10.5-11.5 | 0.35 | 0.01 | 0.450 | 0.024 | 1.7-2.0 | 1515-1535 |
4. Economic benefits are as follows: the process implementation stage is earlier than the month, and the total saving is 1030 ten thousand yuan.
(1) The productivity value is improved: the total nickel produced in 2021 year in month 3 is 237075 nickel dots, the total nickel produced in month 4 is 247844 nickel dots, the total nickel produced in month 5 is 232305 nickel dots, the total nickel produced in month 6 is 257696 nickel dots, the total nickel produced in month 7 is 259366 nickel dots, and 25000 nickel dots are added in each month. In addition, after the process is reformed, the cost of the single nickel is controlled to be 800 yuan/ni point, at least 800 ni points (calculated according to 30 days) can be produced averagely in the prior art every day, the average increase total amount per month is 24000 ni points, the profit of each ni point is about 200 yuan/ni point according to the current market acquisition price, and the profit can be increased by 480 ten thousand yuan per month.
(2) The consumption of the coke is reduced, namely the consumption of the coke in three months of 3.4.5 months in 2021 is about 0.038/Ni, the consumption of the coke in 6 months is 0.035/Ni, and the consumption of the coke in 7 months is 0.034/Ni; before process development, the cost of nickel points consumed by the coke is 50 yuan/nickel point, and the cost of nickel points consumed by the coke is reduced to 36 yuan/nickel point (the data is influenced by price quotation of raw material coke); after the process is implemented, the monthly consumption of the coke/nickel points and the cost of the nickel points are reduced by 8 percent and 28 percent respectively, so that the coke cost can be saved by about 350 ten thousand yuan per month compared with the average coke cost before the process is implemented.
(3) The electricity consumption of the nickel points is averagely reduced by 15 degrees, the total nickel amount is 259366 nickel points calculated according to 7 months, the unit price of the electricity degree is 0.49 yuan, and the cost of the electricity fee is saved by 200 ten thousand yuan per month compared with the cost of the electricity fee averagely before the process is implemented.
Table 11: production data statistical table for 3-7 months
| Month of the year | Molten iron yield (ton) | Average nickel point | Consumption of Yueyaiding (ton) | Nickel point power consumption (KWH) | Total nickel content of moon (individual) | Consumption of mono-nickel coke |
| 7 month | 21704.26 | 11.95 | 8801.01 | 339 | 259366 | 0.034 |
| 6 month | 23512.43 | 10.96 | 9015.879 | 340 | 257696 | 0.035 |
| Month 5 | 21061.21 | 11.03 | 9056.801 | 357 | 232305 | 0.039 |
| 4 month | 22779.82 | 10.88 | 9091.71 | 356 | 247844 | 0.037 |
| 3 month | 22012.53 | 10.77 | 9110.091 | 353 | 237075 | 0.038 |
The above description is only for the purpose of illustrating the present invention and is not intended to limit the scope of the present invention, and any person skilled in the art can substitute or change the technical solution of the present invention and its conception within the scope of the present invention.
Claims (10)
1. A method for smelting nickel molten iron with low cost and high yield is characterized by comprising the following steps:
s1 crushing and mixing: crushing, screening, mixing and stirring large blocks of laterite-nickel ore stones to uniformly mix the large blocks of laterite-nickel ore stones;
s2 drying: drying the raw ore in the step S1 by using a drying kiln to control the moisture of the raw ore to be 23-26%;
s3, batching: the raw ore is proportioned to meet the following requirements: the furnace grade is 1.45-1.64%, the iron TFe is 18.5-20%, the Si/Mg ratio is 1.50-1.55, and the slag alkalinity R is 0.65;
s4 calcination: calcining the raw material proportioned in the step S3 in a rotary kiln to obtain clinker, so as to obtain red hot calcine;
s5 smelting: and smelting and roasting in a submerged arc furnace to obtain the qualified ferronickel aquatic product.
2. A low cost, high productivity process for smelting molten nickel iron according to claim 1 wherein: in the step S4, the calcination temperature of the calcine in the rotary kiln is 710-730 ℃.
3. A low cost, high productivity process for smelting molten nickel iron according to claim 1 wherein: in the step S4, the coal feeder of the rotary kiln workshop is a CWF-1200, 20 ton coal feeder, and the feeding amount of the kiln is 900rpm/100 t.h-930 rpm/110 t.h.
4. A method for low cost, high productivity molten nickel iron smelting according to claim 3, wherein: the kiln head of the rotary kiln is provided with a Roots blower, an air outlet of the Roots blower is blown into the rotary kiln from three channels divided by the kiln head cover, and the air flow direction is horizontal to the central line of the rotary kiln.
5. The method of low-cost, high-capacity smelting of nickel-iron according to claim 4, characterized by: the wind pressure of the Roots blower is 49Kpa, and the wind volume is 79.4m3/min。
6. The method of low-cost, high-capacity smelting of nickel-iron according to claim 5, characterized by: in the step S4, the output rate of the calcine is more than or equal to 68.5 percent; the tail ash discharge amount is less than or equal to 6 percent; the carbon content of the tail ash is less than or equal to 1.5 percent.
7. A low cost, high productivity process for smelting molten nickel iron according to claim 1 wherein: in the step S5, the moisture content of the coal in the ore-smelting furnace is less than or equal to 7 percent, and the weight percentage of the small-charge coke pieces to the medium-charge coke pieces is 20-33: 80-67, wherein the particle size of the small material coke dices is 5-20mm, and the particle size of the medium material coke dices is 10-35 mm.
8. A low cost, high productivity process for smelting molten nickel iron according to claim 1 wherein: in the step S5, the clearance height from the core material level to the furnace cover in the submerged arc furnace is 400-500mm, and the clearance height from the peripheral material level to the furnace cover is 2.0-2.1 m.
9. A low cost, high productivity process for smelting molten nickel iron according to claim 1 wherein: in the step S5, the transformer of the submerged arc furnace is 13000KVA, the operation voltage level is 17-20, the voltage is 483-443V, the power is 31000-33000KWH, and the current is 43000A.
10. A low cost, high productivity process for smelting molten nickel iron according to claim 1 wherein: slag FeO after smelting is 10.5-11.5%, NiO is 0.045-0.055%; and the molten iron Ni is 10.5-11.5%.
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| CN112080649A (en) * | 2020-08-10 | 2020-12-15 | 广东广青金属科技有限公司 | Process for smelting ferronickel from laterite-nickel ore under high power of submerged arc furnace |
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| CN110819791A (en) * | 2019-12-19 | 2020-02-21 | 广东广青金属科技有限公司 | Production process of nickel-containing molten iron with low iron distribution and low silicon-magnesium ratio for submerged arc furnace |
| CN112080649A (en) * | 2020-08-10 | 2020-12-15 | 广东广青金属科技有限公司 | Process for smelting ferronickel from laterite-nickel ore under high power of submerged arc furnace |
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