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CN-121591240-B - Method for comprehensively utilizing high-iron bauxite through lattice activation pretreatment

CN121591240BCN 121591240 BCN121591240 BCN 121591240BCN-121591240-B

Abstract

A method for comprehensively utilizing high-iron bauxite through lattice activation pretreatment includes such steps as respectively breaking and grinding high-iron bauxite and mineralizer to obtain raw materials with uniform granularity, uniformly mixing treated high-iron bauxite with mineralizer and lattice modifier according to a set liquid-solid ratio to obtain mixed ore pulp, ultrasonic reinforcing the mixed ore pulp to obtain pretreated ore pulp, drying the pretreated ore pulp to obtain pretreated ore, decomposing and activating the pretreated ore to obtain activated ore, and so on. The invention adopts the synergistic process of lattice modification, decomposition activation, high-temperature dissolution and magnetic separation, realizes the efficient coupling with the existing Bayer process system, improves the actual dissolution rate of alumina to more than 95 percent, improves the iron recovery rate to more than 70 percent, obtains high-quality iron concentrate with Tfe content more than or equal to 60 percent and Al 2 O 3 content less than or equal to 3 percent, realizes the great reduction and high-value utilization of red mud from the source, and has both environmental protection and economic benefit.

Inventors

  • PAN XIAOLIN
  • Zheng Haozhuo
  • LIU JILONG
  • YU HAIYAN

Assignees

  • 东北大学

Dates

Publication Date
20260508
Application Date
20260129

Claims (10)

  1. 1. The method for comprehensively utilizing the high-iron bauxite by the lattice activation pretreatment is characterized by comprising the following steps of: the raw material preparation in the step (1) is that high-iron bauxite and mineralizer are respectively crushed and finely ground to obtain raw materials with uniform granularity for standby; Step (2) ore pulp is mixed, the treated high-iron bauxite and the mineralizer and the lattice modifier are uniformly mixed according to a set liquid-solid ratio to obtain mixed ore pulp, and an enhancer for improving the lattice modification effect is added in the mixing process; specifically, the lattice modifier is a hydroxyl polymer, and comprises polyalcohol, starch and modified substances thereof, and the reinforcing agent is one or more of organic alcohol, amine or ketone; Step (3) lattice modification, namely carrying out ultrasonic reinforced mineral lattice modification treatment on the mixed ore pulp to obtain pretreated ore pulp; step (4) ore pulp drying, in which tail gas generated in the decomposition and activation process in step (5) is used as a heat source to dry the pretreated ore pulp to obtain pretreated ore; Decomposing and activating, namely decomposing and activating pretreated ores by using waste heat generated in the roasting process of aluminum hydroxide in the Bayer process flow as a heat source to obtain activated ores; The step (6) of high-temperature leaching, which is to carry out high-temperature leaching on the activated ore, and carry out solid-liquid separation after the reaction to obtain a leaching solution and structural red mud mainly containing magnetic iron minerals; And (7) separating and recycling, namely, allowing the dissolved solution to enter a Bayer process flow for conventional alumina production, performing magnetic separation on structural red mud to obtain iron concentrate and magnetic separation tailings, and performing secondary magnetic separation on the magnetic separation tailings.
  2. 2. The method for comprehensively utilizing high-iron bauxite by cell activation pretreatment according to claim 1, wherein the content of Al 2 O 3 in the high-iron bauxite in the step (1) is 25-50%, the content of Fe 2 O 3 is 20-40%, the content of SiO 2 is 1-15%, the content of TiO 2 is 1-5%, and the part with the particle size less than or equal to 100 μm accounts for more than or equal to 90% of the total mass.
  3. 3. The method for comprehensively utilizing the high-iron bauxite by the lattice activation pretreatment of claim 1, wherein the mineralizer in the step (1) is one or a mixture of more than one of industrial lime, carbide slag and calcium aluminate, the mineralizer is not limited by proportion, the adding amount is 0.1% -10% of the mass fraction of the high-iron bauxite, and the part with the particle size less than or equal to 100 μm accounts for more than or equal to 90% of the total mass.
  4. 4. The method for comprehensively utilizing high-iron bauxite through the lattice activation pretreatment of claim 1 is characterized in that the addition amount of the lattice modifier in the step (2) is 0.1-10% of the weight of the dry basis of the high-iron bauxite, the addition amount of the reinforcing agent is 5-20% of the weight of the lattice modifier, and the liquid-solid ratio is 1-2.
  5. 5. The method for comprehensively utilizing high-iron bauxite by using the lattice activation pretreatment of claim 1, wherein in the step (3), the ultrasonic power used for the lattice modification treatment is 300-500W, and the treatment time is 15-60 min.
  6. 6. The method for comprehensively utilizing high-iron bauxite by cell activation pretreatment according to claim 1, wherein in the step (5), the temperature of the activation treatment is 120-300 ℃, and the time of the activation treatment is 30-120 min.
  7. 7. The method for comprehensively utilizing high-iron bauxite by cell activation pretreatment according to claim 1, which is characterized in that the concentration of caustic alkali in the circulating mother solution used in the high-temperature dissolution process in the step (6) is 140-240 g/L, the molecular ratio is 2.6-3.2, the dissolution temperature is 220-280 ℃, and the dissolution time is 15-90 min.
  8. 8. The method for comprehensively utilizing high-iron bauxite by cell activation pretreatment according to claim 1, wherein the phase composition of the structural red mud in the step (6) comprises, but is not limited to, magnetite, maghemite, hematite, hydrated sodium aluminosilicate and hydrated garnet.
  9. 9. The method for comprehensively utilizing high-iron bauxite by cell activation pretreatment according to claim 1, wherein the magnetic separation times in the step (7) are one or more times, the magnetic field strength is 5000-20000 Oe, and the pulse stroke frequency is 50-300 times/min.
  10. 10. The method for comprehensively utilizing high-iron bauxite by cell activation pretreatment according to claim 1, wherein TFe content is more than or equal to 60% and Al 2 O 3 content is less than or equal to 3% in mass percent in iron concentrate in the step (7), the actual dissolution rate of alumina is more than or equal to 95%, and the iron recovery rate is more than or equal to 75%.

Description

Method for comprehensively utilizing high-iron bauxite through lattice activation pretreatment Technical Field The invention belongs to the technical field of metallurgy, and particularly relates to a method for comprehensively utilizing high-iron bauxite by lattice activation pretreatment. Background China is the biggest alumina production country worldwide, but bauxite resources are relatively deficient, and mainly low-grade complex bauxite. The low-grade high-iron bauxite is taken as an important resource, the domestic reserve of the low-grade high-iron bauxite is proved to be more than 10 hundred million tons, however, the resource of the low-grade high-iron bauxite is generally lower in aluminum silicon ratio, the iron aluminum mineral is complicated to be embedded, the low-grade high-iron bauxite belongs to typical refractory ores, meanwhile, a large amount of foreign bauxite is imported in China every year for 2 hundred million tons, the high-iron bauxite is mainly high-iron bauxite, the high-iron bauxite contains a large amount of aluminum hematite and aluminum needle iron ore, and the common Al 3+ is used for replacing Fe 3+ in a similar manner, so that the dissociation of iron aluminum mineral monomers is difficult. Aiming at the high-iron bauxite, the current mainstream treatment process is Bayer process direct digestion, and the digested red mud is subjected to strong magnetic separation to recover iron. However, the existing treatment process mainly aims at extracting aluminum oxide, does not consider the high-efficiency comprehensive utilization of iron and aluminum minerals on the whole, and is characterized by low aluminum oxide dissolution rate, low grade of iron concentrate obtained by magnetic separation, only 40% -50%, low comprehensive recovery rate of iron and aluminum elements, large red mud emission and poor overall economy, and the development of a process for synchronously improving the utilization rate of iron and aluminum elements from the source is needed for solving the problem. Patent [ CN113683106A ] proposes a method for producing alumina by a calcium-free or low-calcium Bayer process. The method aims at diasporic bauxite, adopts iron powder and ether cellulose as additives, and aims at reducing or avoiding adverse effects of lime in the alumina production process, however, a large amount of hydrogen is generated in the reduction leaching stage, which not only brings higher requirements on the pressure resistance of equipment, but also has certain potential safety hazard. Patent [ CN118594752A ] proposes a method for classifying and utilizing high-iron bauxite. The method sequentially carries out grinding and reselection treatment on the high-iron bauxite to obtain high-aluminum high-iron low-silicon low-titanium ore pulp and low-aluminum low-iron high-silicon high-titanium ore pulp, and adopts a high-temperature and low-temperature Bayer process system to treat the high-iron bauxite respectively, and the method can improve the alumina dissolution rate of the high Wen Baier process system, but has the problems of long process flow, low ore utilization rate and the like. The patent [ CN102583477A ] provides a comprehensive utilization method of high-iron low-grade bauxite, which realizes the efficient separation and comprehensive recovery of aluminum and iron, and the recycling of materials in the system, thereby improving the utilization rate of resources. However, the method has the advantages of complex process flow, high energy consumption, dependence on excessive lime and reducing agent, and great challenges in equipment investment, running cost and environmental protection. Disclosure of Invention In view of the defects and shortcomings of the prior art, the invention provides a method for comprehensively utilizing high-iron bauxite by lattice activation pretreatment, which adopts a lattice modification strategy to directionally embed a specific lattice modifier into mineral lattices of the high-iron bauxite, and pre-constructs lattice defects to damage the structural integrity of the high-iron bauxite, so that the crystal face spacing of the high-iron bauxite is enlarged, the specific surface area is increased, the high-efficiency dissociation of aluminum minerals and the directional magnetization of iron minerals are realized, the aluminum is promoted to be decomposed and released to improve the dissolution rate, and the goethite, the goethite and the hematite are converted into magnetite and maghemite in situ, thereby realizing the cascade high-efficiency utilization of iron-aluminum elements. The method comprises the following steps: the raw material preparation in the step (1) is that high-iron bauxite and mineralizer are respectively crushed and finely ground to obtain raw materials with uniform granularity for standby; Step (2) ore pulp is mixed, the treated high-iron bauxite, the mineralizer and the lattice modifier are uniformly mixed according to a set liquid-