CN102936650A - Method for comprehensively utilizing red mud and high-phosphorus iron ore - Google Patents

Abstract

The invention relates to a method for comprehensive utilization of red mud and high-phosphorus iron in aluminum metallurgy, in particular to a solid-state dephosphorization and iron-raising technology for red mud and high-phosphorus iron ore. The method comprises the following preparation steps: a. uniformly mixing powdery high phosphorus iron ore, powdery red mud and coal powder according to the ratio of 100:1-100:1-100; b. mixing the mixed material in step a at 100 ℃～900℃ and heating for 10min～300min; c. After the material in step b is cooled, soak in water for 10～120min and then filter out the liquid; d. Magnetically separate the solid filtered out in step c, and the magnetic part It is hematite or magnetite or iron concentrate, and its phosphorus content is less than 0.3wt%. The method of the invention can effectively utilize the red mud, thereby reducing its pollution to the environment; at the same time, it can reduce the phosphorus content of the high-phosphorus iron ore to make it a resource. The process of the method is simple, the production cost is low, and it is beneficial to industrialization promotion.

Description

A method for comprehensive utilization of red mud and high phosphorus iron ore

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technical field

The invention belongs to the field of energy and metallurgical metals, and in particular relates to a comprehensive utilization method of red mud and high-phosphorus iron in aluminum metallurgy, specifically a technology for solid-state dephosphorization and iron extraction of red mud and high-phosphorus iron ore.

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Background technique

Red mud is the solid residue obtained after extracting alumina from bauxite with alkali. It is one of the main factors that cause environmental pollution in the process of alumina production. The main components of red mud are SiO ₂ , CaO, Fe ₂ O _3. Al ₂ O ₃ , Na ₂ O, TiO ₂ and certain rare earth elements and trace radioactive elements. Generally, about 1.0-1.7 tons of red mud are produced for every ton of alumina produced. According to incomplete estimates, the world discharges about 60 million tons of red mud every year. my country is the world's fourth largest producer of alumina, and its accumulated red mud stockpile has reached 41 million tons. A large amount of red mud is stored in the open air, occupying farmland and hills, and the dust is flying, causing environmental and air pollution. The pH of red mud is very high, and the pH value of its leachate is about 12.1 to 13.0. The lye in the red mud seeps into the formation with the rainwater, causing the pollution of the groundwater source. At present, the utilization rate of red mud is only about 4%, and an effective way to utilize red mud in large quantities has not been found so far.

The amount of red mud produced by aluminum metallurgy is huge. At present, the extraction of iron from red mud is mainly to use high-iron red mud magnetic separation and separation of iron concentrates; direct reduction of iron requires high temperature operation and complex equipment and process conditions. Can not meet the industrial requirements, the use of red mud as a civil construction material has achieved practical application effect, but the amount of red mud to be processed is small.

The main treatment methods of red mud are: using red mud to produce cement (Ren Dongmei, Mao Yanan. Comprehensive utilization of red mud [J]. Nonferrous Metal Industry, 2002, [5]: 57-58); carbon reduction of iron in red mud, Magnetic separation recovery method (Liao Chunfa, Jiang Guoping, Iron Recovery Technology from Red Mud, China Mining, Volume 16, Phase 2. February 2007); CN101275182 SiO ₂ and Fe in red mud under high temperature conditions ₂ O ₃ is reduced to ferrosilicon alloy, Al ₂ O ₃ and CaO to form calcium aluminate, Na ₂ O and K ₂ O are volatilized at high temperature, refined, cooled and precipitated, crushed and separated to obtain calcium aluminate material and ferrosilicon alloy; CN101463426 discloses a comprehensive red mud treatment method including the steps of chlorination roasting, slag disposal, precipitation of mixed rare earth slag, dry dust and circulating fluid disposal.

There are huge reserves of high-phosphorus iron ore in North America, Northern Europe, Australia, Saudi Arabia, and the Yangtze River Basin in my country. In my country, the proven reserves of oolitic high-phosphorus iron ore in the western Hubei area are as high as 4 billion tons, and the total reserves are about 7.45 billion tons, but they have not been effectively utilized yet. my country's iron ore resources are widely distributed, with various genetic types, more lean ore, less rich ore, and many symbiotic components in iron ore deposits. Among the 1,834 identified iron mines, the total proven reserves are 53.14 billion tons, and the reserved reserves are 50.12 billion tons. Among them, the reserved reserves of high-phosphorus iron ore are 7.45 billion tons, accounting for 1.486 billion tons of the total iron ore reserves in the country. %. my country's high-phosphorus iron ore is mainly distributed in Yunnan, Sichuan, Hubei, Hunan, Anhui, Jiangsu and Inner Mongolia in North China in the Yangtze River Basin. It has a wide distribution and large reserves, but its mineral composition is complex, and the particle size of phosphorus minerals embedded Small, the relationship between phosphorus minerals and iron minerals is complex, the connection is strong, and it is a refractory ore. For a long time, due to the failure to develop an ideal method for reducing phosphorus, the existing domestic iron ore resources cannot be effectively utilized, and some mines have stopped mining due to high phosphorus content.

Phosphorus in high phosphorus iron ore is mainly in the form of apatite or fluoroapatite, which is symbiotic with other minerals, disseminated on the grain edges of iron oxide minerals, embedded in quartz or carbonate minerals, and a small amount occurs in iron In the crystal lattice of minerals, apatite crystals are mainly columnar, needle-shaped, aggregated or scattered in iron minerals and gangues. The particle size is small and difficult to separate. It is a refractory mineral. It cannot be dephosphorized during the beneficiation process, so it cannot be fully utilized at present.

Blast furnaces basically do not have the ability to dephosphorize. If such a high phosphorus content is put into the molten iron pretreatment and steelmaking process, it will inevitably bring a heavy economic burden to the steelmaking process. Come big craft trouble. Therefore, if it can be dephosphorized before entering the blast furnace, it can not only save the cost of pretreatment, but also avoid the trouble of the steelmaking process.

Reducing the phosphorus content in the ore before entering the blast furnace is still difficult to solve by relying on the existing technology. The existing research routes of high phosphorus iron ore mainly include acid leaching dephosphorization, alkali leaching dephosphorization, reduction gasification dephosphorization and so on. The existing technology still needs to be improved in aspects such as cost and environmental protection.

Invention patents CN101862701A and CN102513203A provide a method for reverse flotation dephosphorization and scavenging dephosphorization of high-phosphorus-sulfur siderite to make rational use of high-phosphorus-sulfur siderite resources.

At present, there is no method for comprehensive utilization of red mud and high-phosphorus hematite at the same time.

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Contents of the invention

At the same time, the present invention solves the problem of environmental pollution caused by unusable red mud and the problem of phosphorus reduction of high-phosphorus iron ore. The present invention achieves the purpose of "treating waste with waste" through red mud + high-phosphorus iron ore solid-state reduction conversion technology.

In order to solve the above problems, the present invention adopts the following technical solutions.

A method for comprehensive utilization of red mud and high phosphorus iron ore, comprising the following preparation steps:

a. Mix the powdery high phosphorus iron ore, powdery red mud and coal powder according to the weight ratio of 100:1～100:1～100;

b. Heat and keep the mixed material in step a within the temperature range of 100°C to 900°C for 10min to 300min;

c. After the material in step b is cooled, soak in water for 10-120 minutes and then filter out the liquid;

d. The solid filtered out in step c is separated by magnetic separation, and the magnetic part is hematite or magnetite or iron concentrate.

The preferred solution is that the weight ratio of the powdered high phosphorus iron ore, powdered red mud and coal powder in step a is 1:1:1.

Preferably, the water used for soaking in step c is circulating water.

Preferably, the filtered liquid in step c can be used for the preparation of phosphate fertilizer. the

The preferred solution is that the non-magnetic part after magnetic separation in step d can be used for metal recovery, and the metal is aluminum, titanium, rare scattered metals, rare rare earth metals and the like.

The red mud in the present invention is the red mud produced in aluminum metallurgical process.

The main components of the high-phosphorite iron ore in the present invention: TFe is 35-60wt%, and the P content is 0.4-1.8wt%.

The preferred solution is that in the magnetic part of the low-phosphorite iron ore obtained by magnetic separation in step d, the content of phosphorus is less than 0.3wt%

The principle of the present invention is to use the method of low-temperature solid-state ore phase conversion to convert the insoluble phosphate in high-phosphorite iron ore into soluble phosphate by using alkaline red mud The iron oxide is reduced to magnetite or iron concentrate, and then through solid-liquid separation, the phosphate is transferred to the aqueous solution to achieve the purpose of dephosphorization, and the remaining solid part can be separated by magnetic separation. Low phosphorus magnetite or iron concentrate.

The beneficial effect of the present invention is that through the phase conversion technology of red mud and high-phosphorite iron ore solid-state reduction ore, the high-phosphorite ore that cannot enter the blast furnace for ironmaking and a large amount of waste red mud produced by aluminum smelting will be comprehensively utilized, and the unusable The resources are effectively utilized, and a large number of piled up wastes are turned into resources for reuse, so as to achieve the purpose of "treating waste with waste". The invention can effectively utilize the red mud, thereby reducing its pollution to the environment; at the same time, it can reduce the phosphorus content of the high-phosphorus iron ore and turn it into a resource. The technology of the invention is simple, the production cost is low, and it is beneficial to industrialization promotion.

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Detailed ways

Example 1

A method for comprehensive utilization of red mud and high phosphorus iron ore of the present invention comprises the following preparation steps:

a. Mix 1kg of high-phosphorus iron ore, 10g of red mud and 10g of coal powder evenly. The main components of red mud are: SiO2 12wt%, CaO 3.5wt%, Fe ₂ O ₃ 38wt%, Al ₂ O ₃ is 18wt%, Na ₂ O is 9 wt%, TiO ₂ is 1.5wt%; the main components of ferrite: TFe is 50wt%, Al ₂ O ₃ is 5wt%, P is 1.28wt%;

b. Heat the mixed material described in step a to 100°C and keep it warm for 10min;

c. After the reaction in step b is completed, it is lowered to room temperature, soaked in water for 10 minutes, and the liquid is filtered out, and it is recycled for the preparation of phosphate fertilizer;

d, the solid filtered out in step c is subjected to magnetic separation to obtain hematite; the non-magnetic part obtained is a mixture of aluminum, silicon, titanium and other valuable metal salts in high phosphorus iron ore and red mud, which can be Part of the recycling of aluminum, titanium, rare scattered metals, rare rare earth metals, etc.

After analysis and testing, the obtained product is hematite, and its P content is 0.3wt%.

Example 2

A method for comprehensive utilization of red mud and high phosphorus iron ore of the present invention comprises the following preparation steps:

a. Mix 1kg of high-phosphorus iron ore, 500g of red mud and 100g of coal powder evenly. The main components of red mud are: SiO2 _is 12wt%, CaO is 3.5wt%, _Fe2O3 is 38wt%, _Al2 O ₃ is 18wt%, Na ₂ O is 9 wt%, TiO ₂ is 1.5wt%; the main components of ferrite: TFe is 50wt%, Al ₂ O ₃ is 5wt%, P is 1.28wt%;

b. Heating the mixed material described in step a to 500°C and keeping it warm for 300min;

c. After the reaction in step b is completed, it is lowered to room temperature, soaked in circulating water for 60 minutes, and then filtered out the liquid;

d. The solid filtered out in step c is separated by magnetic separation to obtain magnetite; the aluminum, titanium, rare scattered metals, and rare rare earth metals in the high phosphorus iron ore and red mud enter the non-magnetic part for recycling.

After analysis and testing, the obtained product is magnetite, and phosphorus in iron: 0.15%.

Example 3

A method for comprehensive utilization of red mud and high phosphorus iron ore of the present invention comprises the following preparation steps:

a. Mix 500g of high-phosphorus iron ore, 500g of red mud and 500g of coal powder evenly. The main _components of red mud are: SiO2 is 12wt%, CaO is 3.5wt%, _Fe2O3 is 38wt%, _Al2 O ₃ is 18wt%, Na ₂ O is 9 wt%, TiO ₂ is 1.5wt%; the main components of ferrite: TFe is 50wt%, Al ₂ O ₃ is 5wt%, P is 1.28wt%;

b. Heat the mixed material described in step a to 900°C and keep it warm for 120min;

c. After the reaction in step b is completed, it is cooled to room temperature, soaked in water for 120min, and then filtered out the liquid;

d. The solid filtered out in step c is separated by magnetic separation to obtain iron concentrate; the aluminum and titanium in the high phosphorus iron ore and red mud enter the non-magnetic part for recycling.

After analysis and testing, the obtained product is iron concentrate with a phosphorus content of 0.08wt%.

Claims (8)

1. a method for comprehensive utilization of red mud and high phosphorus iron ore, is characterized in that: comprise following preparation steps: a. Mix the powdery high phosphorus iron ore, powdery red mud and coal powder according to the weight ratio of 100:1～100:1～100; b. Heat and keep the mixed material in step a within the temperature range of 100°C to 900°C for 10min to 300min; c. After the material in step b is cooled, soak in water for 10-120 minutes and then filter out the liquid; d. The solid filtered out in step c is separated by magnetic separation, and the magnetic part is hematite or magnetite or iron concentrate. 2. the method for comprehensive utilization of a kind of red mud and high phosphorus iron ore according to claim 1, is characterized in that: the weight ratio of described powdery high phosphorus iron ore, powdery red mud, pulverized coal in step a is 1:1:1. 3. A method for comprehensive utilization of red mud and high phosphorus iron ore according to claim 1, characterized in that: the liquid filtered out in step c can be used for the preparation of phosphate fertilizer. 4. A method for comprehensive utilization of red mud and high phosphorus iron ore according to claim 1, characterized in that: after magnetic separation in step d, the obtained non-magnetic part can be used for metal recovery, and the metal is aluminum , titanium, rare scattered metals, rare rare earth metals. 5 . The method for comprehensive utilization of red mud and high phosphorus iron ore according to claim 1 , characterized in that: the red mud is the red mud produced in the process of aluminum metallurgy. 6. A method for comprehensive utilization of red mud and high-phosphorite ore according to claim 1, characterized in that: the content of TFe, the main component of high-phosphorite ore, is 35-60wt%, and the content of P is 0.4-1.8wt%. 7. A method for comprehensive utilization of red mud and high-phosphorite iron ore according to claim 1, characterized in that: in the magnetic part low-phosphorite iron ore obtained by magnetic separation in step d, the content of phosphorus is less than 0.3 wt%. 8. A method for comprehensive utilization of red mud and high phosphorus iron ore according to claim 1, characterized in that: the water used for soaking in step c is circulating water.