CN-117660753-B - Method for producing ferronickel by selective reduction, synchronous drying and dehydration of silicon-magnesium laterite nickel ore and electric furnace smelting

Abstract

A process for preparing ferronickel from Si-Mg laterite-nickel ore includes such steps as crushing Si-Mg laterite-nickel ore, loading it in storage bin, cyclone preheating, removing adsorbed water, heating to remove structural water, gas-solid separation to obtain primary solid material, loading it in reduction reactor, preheating, high-temp fume, loading it in reduction reactor, introducing nitrogen gas and methane or natural gas, flowing out of reduction material, loading the secondary solid material, and cooling. The method solves the practical problems of easy ring formation, low operation efficiency, high power consumption and the like of the rotary kiln in the rotary kiln prereduction-electric furnace smelting process.

Inventors

• HAN YUEXIN
• YU JIANWEN
• LI PEIYU
• LI YANJUN
• GAO PENG
• JIN JIANPING
• SUN YONGSHENG

Assignees

• 东北大学

Dates

Publication Date

20260505

Application Date

20231206

Claims (4)

1. 1. The method for producing ferronickel by selectively reducing and synchronously drying and dehydrating silicon-magnesium laterite-nickel ore and smelting in an electric furnace is characterized by comprising the following steps of: step (1) of crushing Crushing the silicon-magnesium laterite nickel ore until the granularity is less than or equal to 1.5mm, wherein the part with the granularity less than 0.074mm accounts for 25-40% of the total mass, feeding the material into a feed bin, wherein the silicon-magnesium laterite nickel ore contains 7.5-20% of TFe, 2 -45% of SiO, 20-35% of MgO and less than or equal to 15% of water in percentage by weight; Step (2) preheating and drying Feeding the silicon-magnesium type laterite-nickel ore in the storage bin into a multi-stage cyclone preheating and drying system, wherein the preheating temperature is 400-550 ℃, the ratio of the volume flow of gas entering the multi-stage cyclone preheating system to the mass flow of mixed materials is 0.10-0.30 m 3 /kg, after the adsorption water of the silicon-magnesium type laterite-nickel ore is removed by the preheating airflow, feeding the silicon-magnesium type laterite-nickel ore into a fluidization roasting main furnace heating system to heat for 5-10 s to remove structural water, the heating temperature is 800-1000 ℃, forming a drying material, and returning high-temperature flue gas after gas-solid separation of the drying material to the preheating and drying system to continuously preheat the silicon-magnesium type laterite-nickel ore; step (3) of selective reduction The dry material is subjected to gas-solid separation to form a primary solid material, the primary solid material is fed into a fluidized bed reduction reactor, nitrogen and methane or natural gas are respectively fed into a nitrogen inlet and a reducing gas inlet of the fluidized reduction reactor, the primary solid material is in a fluidized state under the action of the nitrogen and the methane or the natural gas, and is subjected to selective reduction reaction with the methane in the reduction reactor at the temperature of 600-700 ℃ to form a reduction material, the metallization rate of nickel in the reduction material is more than or equal to 90%, the metallization rate of iron is less than or equal to 20%, and excess methane is returned to a fluidized roasting main furnace for combustion heat supply after the reduction material is subjected to gas-solid separation; step (4) electric furnace smelting Mixing a secondary solid material formed by gas-solid separation of a reduction material with quartz sand or magnesia flux to adjust the silicon-magnesium ratio in the secondary solid material, feeding the mixture into an electric furnace smelting reactor, discharging the mixture from a nickel iron water discharge port and a slag discharge port after smelting, cooling the mixture to obtain nickel-iron alloy and slag, adding the quartz sand or magnesia flux to adjust the mass ratio of SiO 2 /MgO in the secondary solid material to be (1.4-1.7): 1, wherein the mass of the added quartz sand or magnesia flux accounts for 8-30% of the mass of the laterite-nickel ore raw material.
2. 2. The method for producing ferronickel by selective reduction synchronous drying dehydration-electric furnace smelting of silicon-magnesium laterite-nickel ore according to claim 1, wherein in the step (3), the retention time of primary solid materials in a reduction reactor is 30-60 min, the ratio of the volume flow of methane and nitrogen entering the reduction reactor to the mass flow of the primary solid materials is 0.06-0.40 m 3 /kg, and the volume concentration of methane gas entering the reduction reactor is 20-30%.
3. 3. The method for producing ferronickel by selective reduction, synchronous drying and dehydration and electric furnace smelting of silicon-magnesium laterite-nickel ore, which is disclosed in claim 1, is characterized in that in the step (4), the electric furnace smelting temperature is 1550-1600 ℃ and the smelting time is 30-90 min.
4. 4. The method for producing ferronickel by selective reduction synchronous drying dehydration-electric furnace smelting of silicon-magnesium laterite nickel ore according to claim 1, wherein in the step (4), ni is contained in an alloy of nickel by mass percent of not less than 15%, ni recovery rate of not less than 90%, TFe is contained in an alloy of nickel by mass percent of not more than 80%, and Fe recovery rate of 10-20%.

Description

Method for producing ferronickel by selective reduction, synchronous drying and dehydration of silicon-magnesium laterite nickel ore and electric furnace smelting Technical Field The invention belongs to the technical field of mineral processing and metallurgy, and particularly relates to a method for producing ferronickel by selectively reducing, synchronously drying and dehydrating laterite-nickel ore and smelting in an electric furnace. Background Nickel is an important strategic metal and is widely applied to the fields of stainless steel, batteries, electroplating, catalysts and the like. In actual production, the mainstream and mature process for treating the silicon-magnesium laterite-nickel ore is a rotary kiln pre-reduction-electric furnace smelting (RKEF) process. However, the rotary kiln has the advantages of easy ring formation, low operation rate, high power consumption and high production cost. Therefore, based on the pyrometallurgy process, how to reduce the production cost of the silicon-magnesium laterite-nickel ore is critical. The CN201310449196.8 application discloses a smelting method of silicon-magnesium type laterite-nickel ore, which comprises the following steps of crushing and grinding the silicon-magnesium type laterite-nickel ore to obtain silicon-magnesium type nickel ore pulp, adding calcium carbonate into the silicon-magnesium type nickel ore pulp to neutralize and remove iron and aluminum, and then adding sodium hydroxide to adjust the pH value to obtain a nickel hydroxide product. Adding chromium ore and fluxing agent into nickel hydroxide product, melting into mother liquor in plasma furnace, adding coke for smelting after the mother liquor is completely melted, and simultaneously adding additive to obtain nickel-chromium alloy product. The invention combines the wet process and the fire process, has complex production flow, difficult control of the moisture content of materials, high production cost and difficult large-scale industrialized application. The application CN200810132540.X discloses a smelting method of silicon-magnesium laterite-nickel ore, which comprises the steps of mixing the silicon-magnesium laterite-nickel ore with a vulcanizing agent, briquetting to obtain a briquette with the strength of 4-12 MPa, and putting the briquette, a flux and coke into a blast furnace for smelting to obtain low nickel matte and slag, wherein the process has high energy consumption, high coke dependence degree and serious environmental pollution, and especially has dark industrial application prospect under the background of increasingly strict environmental protection requirements. Therefore, there is a great need to develop an innovative process with environmental protection and low energy consumption and to reduce the production cost of the silicon-magnesium laterite-nickel ore. Disclosure of Invention Aiming at the problems of easiness in looping, low operation efficiency, high power consumption and the like of the conventional rotary kiln prereduction-electric furnace smelting (RKEF) process, the invention provides a method for producing ferronickel by selectively reducing, synchronously drying and dehydrating a silicon-magnesium laterite-nickel ore through electric furnace smelting, which utilizes the characteristics of strong reduction capability of methane to nickel oxide and weak reduction capability to iron oxide, adopts methane as a reducing agent, selectively reduces the nickel oxide into metallic nickel Ni with the metallization rate of more than or equal to 90 percent under the fluidization roasting condition, reduces most of iron oxide into ferrous oxide, and reduces a small amount of ferrous oxide into metallic iron with the metallization rate of less than or equal to 20 percent; in addition, serpentine synchronously completes drying and dehydration in the fluidization selective reduction roasting process, meets the requirement of the next electric furnace smelting process on the moisture content of the material being less than or equal to 1.5 percent, and in the electric furnace smelting process, the mass ratio of silicon to magnesium in the material, namely SiO 2/MgO, is adjusted to be (1.4-1.7) by adding silica or magnesia to be 1, and electric furnace smelting is carried out to obtain high-grade ferronickel and smelting slag, wherein the smelting slag can be used as a raw material for producing cement, and the full-component comprehensive utilization of the silicon-magnesium type laterite-nickel ore is effectively realized. The method for producing ferronickel by selectively reducing and synchronously drying and dehydrating silicon-magnesium laterite-nickel ore through electric furnace smelting specifically comprises the following steps: step (1) of crushing Crushing the silicon-magnesium laterite-nickel ore until the granularity is less than or equal to 1.5mm, wherein the part with the granularity less than 0.074mm accounts for 25-40% of the total mass, an