CN1270830C - Highly efficient ore dressing system of medium-low class aluminium ore - Google Patents

Abstract

The invention relates to a beneficiation method for middle and low-grade bauxite, using middle and low-grade diaspore bauxite as raw material, the main point is to adopt the process of "selective grinding, grading, desliming, concentration and narrow grade flotation" Process, ball mill or vibration mill is used for selective grinding; classification is to separate qualified coarse-grained concentrate, and hydrocyclone is used; desliming and concentration are to remove the slime less than 10 μm and concentrate the pulp to meet the follow-up Flotation requires hydrocyclones for slurry concentration; narrow-grade flotation uses positive flotation technology, flotation reagents: collectors are fatty acids, dispersants are sodium carbonate, coarse-grained concentrates obtained from classification operations and flotation The concentrates are combined to obtain the final mixed concentrate, the aluminum-silicon ratio of the coarse-grained concentrate is greater than 9, the yield is 30-50%, the recovery rate of Al ₂ O ₃ is 40-50%, the aluminum-silicon ratio of the mixed concentrate is 9-10, and the Al ₂ The O ₃ recovery rate is greater than 88%. The process flow structure is simple, the production cost is low, the operation is stable, the index is stable, and it has a strong adaptability to the middle and low grade diaspore bauxite.

Description

High-efficiency beneficiation method for middle and low grade bauxite

technical field

The invention relates to a processing method of bauxite, in particular to a beneficiation method of middle and low grade bauxite.

Background technique

Bauxite is an important strategic resource and an important raw material for alumina industry, refractory material industry and building material industry. The world is rich in bauxite resources, mainly distributed in Australia, Guinea, Vietnam, Jamaica, India, Suriname, Indonesia, Greece and China. The ore types are mainly divided into: gibbsite type, boehmite type and diaspore type. Most of them in foreign countries are gibbsite type, which is characterized by low aluminum and silicon, high aluminum-silicon ratio, and generally high iron oxide content.

my country is rich in bauxite resources, and most of the ore is diaspore type. The aluminum-silicon ratio of bauxite is mostly distributed between 4 and 10, accounting for about 85.61% of the national reserves. Bauxite reserves with an aluminum-silicon ratio greater than 7 only account for 1/3. The distribution ratio of aluminum to silicon is the largest between 4 and 7, and its reserves account for about 60% of the total reserves, and most of them are high-alumina, high-silicon, low-iron, fine-grained diaspore type, washed The selection is difficult, so the conventional Bayer process commonly used abroad cannot be used economically to produce alumina. At present, the main alumina industry in my country adopts the soda lime sintering method and the mixed combination method to produce alumina. However, compared with the conventional Bayer method for processing high-grade bauxite in foreign countries, this production method has high energy consumption and long process flow. , Large construction investment, high manufacturing cost and other shortcomings.

The diaspore type bauxite is mainly composed of four types of minerals: 1) aluminum-containing minerals, mainly diaspore; 2) silicon-containing minerals, including kaolinite, illite and pyrophyllite; 3) Iron minerals, including goethite, limonite, hematite, pyrite, etc.; 4) titanium minerals, including anatase, rutile, etc. Diaspore is mostly produced in the form of aphanitic or microcrystalline aggregates, and is closely related to minerals such as silicon-containing minerals and iron oxide minerals, and its distribution is relatively fine. The characteristics of diaspore bauxite are: high aluminum, high silicon, low aluminum-silicon ratio. The oxide content is also generally lower. Therefore, separating aluminum from silicon and increasing the ratio of aluminum to silicon is the focus of bauxite beneficiation in my country.

At present, the research and development of bauxite process mainly includes the following types:

(1) One-time fine grinding positive flotation process

The characteristic of this technological process is that flotation is carried out directly after a fine grinding, the difference is that the structure of the flotation process is different. In the past, the process of secondary roughing and primary selection was often used. By optimizing the structure of the flotation process, the current common feature is that the number of selections has increased. . Due to fine grinding, the particle size of the concentrate is relatively fine, and a large amount of minerals are muddy, which affects the flotation separation effect, the aluminum-silicon ratio of the concentrate is low, and the consumption of flotation reagents is relatively large.

(2) stage grinding stage sorting process

The characteristic of this technological process is that coarse grinding flotation produces part of the concentrate, and the tailings of the first stage of flotation are regrinded and re-selected. On this basis, a pre-desliming process and a two-stage selective hydrophobic aggregation process were developed. The pre-deliming process before the second-stage grinding is based on the nature of the gangue that is easy to mud. Desliming before the second-stage grinding reduces the impact of the slime on flotation and increases the concentration of the regrinding operation (weight concentration, lower The same) and grinding efficiency; the characteristic of the two-stage selective hydrophobic agglomeration process is that the hydrophobic fine particles are aggregated by introducing mechanical energy, increasing the apparent size of the recycled object, improving the dynamic behavior of fine particle flotation, and increasing the fine particle size. particle recovery.

Although the stage separation process of stage grinding achieves coarse grinding for the first time and breaks through the situation of fine grinding and separation of bauxite, the process is relatively complicated and the consumption of flotation agents is relatively large.

(3) One-stage separation process of stage grinding

The process flow is coarse grinding and flotation of raw ore, classification of flotation tailings, coarse particles are returned for regrinding and re-election, and fine particles are used as final tailings. In theory, a new idea of using diaspore-rich aggregates as the dissociation target, and diaspore and its plenums as the capture and recovery objects is proposed, which breaks through the problem of diaspore intercalation. The technical idea of fine particle size and desiliconization should be finely ground, and make full use of the properties of gangue minerals that are easy to muddy, so that the slime can pass through the process quickly, reducing the impact of the slime on flotation, but the consumption of flotation agents is relatively high. big.

(4) Classification-flotation process

The classification-flotation process uses conventional grinding; and then uses classification operations to divide the raw materials into different particle sizes. It is characterized in that a part of the coarse-grained concentrate is obtained by classification before the flotation operation, and the fine-grained tailings are sorted. Therefore, the amount of processed ore and reagent consumption of flotation operations are reduced. However, the aluminum-silicon ratio of the coarse-grained concentrate is low. When the aluminum-silicon ratio of the raw ore is lower than 5, the aluminum-silicon ratio of the coarse-grained ore is only about 6, which affects the aluminum-silicon ratio of the final mixed concentrate. In addition, the production rate of crude concentrate should be strictly controlled, otherwise the production index will fluctuate easily, and the adaptability to raw materials will be poor; ore slime will affect the flotation index.

(5) Flotation-classification process

On the surface, the process flow is the interchange of classification and flotation in the classification-flotation process, but the coarse particles will still pass through the flotation operation, so the consumption of reagents is greater than that of the classification-flotation process.

(6) Coarse and fine separation process

This process is proposed based on the process mineralogy characteristics of my country's bauxite and the difference between coarse-grained and fine-grained separation conditions. The separation environment improves the separation efficiency and reduces the cost of mineral processing. The process consumes a lot of flotation reagents.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to find a new high-efficiency beneficiation method for low- and medium-grade bauxite, to formulate corresponding technological processes, and to obtain concentrates with an aluminum-silicon ratio greater than 9; The beneficiation efficiency and production capacity of ore are improved, the technological process is simple, the production cost is low, and the quality requirements of the beneficiation concentrate for the production of alumina by the Bayer process are met.

The technical solution to realize the purpose of the present invention is: use low-grade diaspore bauxite as raw material, adopt the technological process of "selective grinding - classification - desliming, concentration - narrow grade flotation" Mineral processing to obtain a concentrate product with an aluminum-silicon ratio greater than 9 and an Al ₂ O ₃ recovery rate greater than 88%, so as to meet the raw material requirements of the Bayer process for alumina production.

The concrete technological parameter of each operation of above-mentioned technological process is:

1. Use middle and low grade diaspore bauxite as raw material, put it into grinding process after crushing;

2. Selective grinding. Using wet ball mill or wet vibration mill

Wet ball mill, its spherical medium ratio is Φ30mm: Φ20mm: Φ15mm=30%: 50%: 20%, the medium filling rate is 40%, the material-ball ratio is 1.2, the rotational speed is 91%, and the grinding weight concentration is 70%. The grinding time is 8 minutes, and the grinding fineness reaches -200 mesh, accounting for 48-55%.

Wet vibrating mill, the proportion of spherical medium is Φ40mm: Φ30mm: Φ20mm = 20%: 30%: 50%, the amplitude is 2.3mm, the medium filling rate is 75%, the grinding weight concentration is 70%, the material-ball ratio is 0.9, the grinding The mining time is 5 minutes, and the product particle size -200 mesh accounts for 48-55%.

3. Classification, the purpose is to separate the qualified concentrate products, and the equipment is hydrocyclone

(1) When the above process uses a wet ball mill to grind ore, the control d ₅₀ is 0.11mm, and the structural parameters and operating parameters of the grading hydrocyclone are as follows:

Diameter of feed pipe/diameter of overflow pipe=0.4～0.8, diameter of overflow pipe/diameter of cyclone=0.2～0.4, diameter of grit chamber/diameter of overflow pipe=0.2～0.5, cone angle of cyclone is 20 °, the ore feeding pressure is 0.06~0.12MPa, and the ore feeding weight concentration is 30~50%.

(2) When the above process adopts wet vibratory grinding ore grinding, the control d ₅₀ is 0.080mm, and the structural parameters and operating parameters of the grading hydrocyclone are as follows:

Diameter of feed pipe/diameter of overflow pipe=0.6～1.0, diameter of overflow pipe/diameter of cyclone=0.2～0.4, diameter of grit chamber/diameter of overflow pipe=0.4～0.7, cone angle of cyclone is 20 °, the ore feeding pressure is 0.1~0.15MPa, and the ore feeding weight concentration is 30~50%.

4. Desliming and concentration, the purpose is to remove the slime less than 10 microns, and concentrate the pulp to meet the requirements of subsequent flotation operations on the concentration of the pulp. The equipment uses a hydrocyclone, and its structural parameters and operating parameters are as follows :

Diameter of feed pipe/diameter of overflow pipe=0.4～0.8, diameter of overflow pipe/diameter of cyclone=0.21～0.4, diameter of sand outlet/diameter of overflow pipe=0.3～0.5, cone angle of cyclone is 15 °, the ore feeding pressure is 0.12~0.20MPa, and the ore feeding weight concentration is 10~30%.

5. Narrow grade flotation, using positive flotation process, pulp weight concentration 30-40%, flotation time 7-10min, flotation reagents and dosage: fatty acids are selected as collectors, dosage is 0.5-1.0kg/t Raw ore; dispersant (regulator) is sodium carbonate, the dosage is 1.5-2.0kg/t raw ore.

6. The coarse-grained concentrate obtained from the classification operation is combined with the flotation concentrate to obtain the final mixed concentrate product.

Compared with the prior art, the present invention has remarkable technical characteristics and benefits: the product index obtained by mineral processing according to the technological process of the present invention can reach:

(1) Coarse-grained concentrate obtained after classification operation: the aluminum-silicon ratio is greater than 9, the yield is 30-50%, and the recovery rate of Al ₂ O ₃ is 40-50%;

(2) The final mixed concentrate: the ratio of aluminum to silicon is 9-10, and the recovery rate of Al ₂ O ₃ is greater than 88%;

(3) The process flow structure is simple, the production cost is low, the operation is stable, the index is stable, and it has a strong adaptability to the middle and low grade diaspore bauxite;

(4) Selective grinding is used to avoid the over-grinding phenomenon of useful minerals caused by conventional grinding, and improve the subsequent flotation operation environment. At the same time, due to the coarser grinding particle size, the grinding energy is saved;

(5) Classification is adopted to obtain some qualified concentrate products, which can reduce the amount of ore processed in subsequent operations, reduce the number of equipment and the amount of flotation reagents; the quality of concentrate products is good (the ratio of aluminum to silicon of coarse-grained concentrate is greater than 9, The aluminum-silicon ratio of the mixed concentrate reaches 9-10), and the index is stable;

(6) The desliming and thickening operations provide good conditions for subsequent flotation operations, and play an important role in the improvement and improvement of flotation indicators;

(7) Narrow-level flotation eliminates the influence of ore slime on the flotation process and indicators, and the separation efficiency is high.

Description of drawings

Fig. 1 is a flow chart of the high-efficiency beneficiation process of medium and low-grade bauxite in the present invention.

In the figure: 1. Selective grinding (wet ball mill or vibration mill), 2. Classification (hydrocyclone), 3. Desliming and concentration (hydrocyclone), 4. Narrow grade flotation

Detailed ways

The raw materials in the following examples are bauxite from Henan Great Wall Aluminum Company. The main aluminum-containing mineral is diaspore. Other minerals mainly include kaolinite, illite, pyrophyllite, goethite and hematite. The results of mineral chemical analysis are shown in the table.

Table raw material chemical analysis results Element Al ₂ O ₃ (%) SiO ₂ (%) Fe ₂ O ₃ (%) TiO ₂ (%) Loss on ignition (%) Impurities (%) Al ₂ O ₃ /SiO ₂ content 65.32 11.10 4.88 3.12 13.64 the remaining 5.88

Example 1: Grinding the pulverized raw materials with a ball mill. The working conditions of the ball mill are as follows: ball mill specification Φ305×305mm, wet ball mill grinding, spherical medium diameter and ratio are Φ30mm: Φ20mm: Φ15mm = 30%: 50%: 20%, medium filling rate is 40%, material-ball ratio is 1.2, the speed rate is 91%, the grinding weight concentration is 70%, the grinding time is 8 minutes, and the grinding fineness reaches -200 mesh, accounting for 48.22%. The obtained product is made into a slurry with a weight concentration of 30%, and is classified by a hydrocyclone, and the d ₅₀ is controlled to be 0.11mm. The diameter of the pipe is 13mm, the diameter of the grit chamber is 6mm, the cone angle is 20°, and the ore feeding pressure is 0.06MPa. Under these conditions, coarse grains with an aluminum-silicon ratio of 9.18, a yield of 43.34%, and an Al ₂ O ₃ recovery rate of 47.05% can be obtained. grade concentrate. The overflow of the hydrocyclone is used for desliming and concentration. The hydrocyclone is used. Its structural parameters are as follows: diameter 50mm, cone angle 15°, diameter of ore feeding port 8mm, diameter of overflow pipe 12mm, diameter of sand settling port 5mm, ore feeding port The pressure is 0.20MPa, and the ore weight concentration is 10%. The overflow of the cyclone is discarded, and the grit is made into a slurry with a certain concentration for flotation. The flotation conditions are as follows: the weight concentration of the slurry is 30%, and the flotation time is 7 minutes; the collector is oxidized paraffin wax soap, and the dosage is 500g/t of raw ore ; Use sodium carbonate as a dispersant in an amount of 1.5kg/t raw ore to obtain a flotation concentrate. Coarse concentrate and flotation concentrate are mixed to obtain the final mixed concentrate, the aluminum-silicon ratio of the mixed concentrate is 9.67, and the recovery rate of Al ₂ O ₃ is 88.94%.

Example 2: Grinding fineness -200 mesh accounts for 52.55%, and the grinding product is made into pulp with a weight concentration of 40%. The feeding pressure of the hydrocyclone in the classification operation is 0.09MPa, and the feeding weight concentration is 40%; desliming, The ore feeding pressure of the hydrocyclone in the concentration operation is 0.12MPa, and the ore weight concentration is 30%; the weight concentration of the flotation pulp is 35%, and the flotation time is 8 minutes. The collector uses sodium oleate, and the dosage is 825g/t. Sodium carbonate is used in an amount of 1.8kg/t raw ore to obtain flotation concentrate. Other conditions are the same as Example 1, and the coarse-grained concentrate with an aluminum-silicon ratio of 9.47, a yield of 43.23%, and an Al ₂ O ₃ recovery rate of 47.89% can be obtained. The aluminum-silicon ratio of the mixed concentrate is 9.38, and the Al ₂ O ₃ recovery The rate is 88.56%.

Example 3: Grinding fineness -200 mesh accounts for 54.96%, and the grinding product is made into slurry with a weight concentration of 50%, for classification operations, the feeding pressure of the hydrocyclone is 0.12MPa, and the feeding weight concentration is 50%; desliming , Concentration operation hydrocyclone feed pressure 0.16MPa, feed ore weight concentration 20%; flotation pulp weight concentration 40%, flotation time 10min, the collector uses a mixture of oxidized paraffin soap and sodium oleate (oxidized paraffin Soap:sodium oleate=1:1, weight ratio), the dosage is 1000g/t raw ore; the dispersant uses sodium carbonate, the dosage is 2.0kg/t, to obtain the flotation concentrate. Other conditions are the same as Example 1, and the coarse-grained concentrate with an aluminum-silicon ratio of 9.28, a yield of 43.52%, and an Al ₂ O ₃ recovery rate of 47.16% can be obtained. The aluminum-silicon ratio of the mixed concentrate is 9.57, and the Al ₂ O ₃ recovery The rate is 88.11%.

Example 4: The raw material is Henan bauxite. Vibration grinding is used to grind ore. The working conditions of the vibration mill are as follows: wet grinding, medium filling rate 75%, grinding weight concentration 70%, material-ball ratio 0.9, spherical medium ratio Φ40mm·Φ30mm: Φ20mm=20%: 30%: 50%, amplitude 2.3mm, when the grinding time is 5 minutes, the product particle size -200 mesh accounts for 48.19%. The obtained product is made into a slurry with a weight concentration of 30%, and is classified by a hydrocyclone, and the d ₅₀ is controlled to be 0.80mm. The diameter of the pipe is 14mm, the diameter of the grit chamber is 6mm, the cone angle is 20°, and the ore feeding pressure is 0.1MPa. Under these conditions, coarse grains with an aluminum-silicon ratio of 9.09, a yield of 46.55%, and an Al ₂ O ₃ recovery rate of 50.67% can be obtained. grade concentrate. The overflow of the hydrocyclone is used for desliming and concentration. The hydrocyclone is used. Its structural parameters are as follows: diameter 50mm, cone angle 15°, diameter of ore feeding port 8mm, diameter of overflow pipe 12mm, diameter of sand settling port 5mm, ore feeding port The pressure is 0.20MPa, and the ore weight concentration is 10%. The overflow of the cyclone is discarded, and the grit is prepared into a slurry with a certain concentration for flotation. The flotation conditions are as follows: the concentration of the slurry is 30%, the flotation time is 7 minutes, and the collector is oxidized paraffin wax soap, and the dosage is 500g/t of raw ore; Sodium carbonate is used as a dispersant in an amount of 1.5kg/t raw ore to obtain a flotation concentrate. Coarse concentrate and flotation concentrate are mixed to obtain the final mixed concentrate, the aluminum-silicon ratio of the mixed concentrate is 9.87, and the recovery rate of Al ₂ O ₃ is 88.61%.

Example 5: Grinding fineness -200 mesh accounts for 51.44%, the weight concentration of the grinding product is 40%, the feeding pressure of the hydrocyclone is 0.15MPa, and the feeding weight concentration is 40%; The ore feeding pressure of the flow device is 0.12MPa, the ore weight concentration is 30%; the weight concentration of the flotation pulp is 35%, and the flotation time is 8 minutes. The collector uses sodium oleate, and the dosage is 825g/t raw ore; The dosage is 1.8kg/t raw ore to obtain flotation concentrate. Other conditions are the same as in Example 4, and the coarse-grained concentrate with an aluminum-silicon ratio of 9.22, a yield of 43.47%, and an Al ₂ O ₃ recovery rate of 47.50% can be obtained. The aluminum-silicon ratio of the mixed concentrate is 9.95, and the Al ₂ O ₃ recovery The rate is 88.17%.

Example 6: Grinding fineness -200 mesh accounts for 55%, the grinding product is made into pulp with a weight concentration of 50%, the feeding pressure of the hydrocyclone in the classification operation is 0.12MPa, and the feeding weight concentration is 50%; desliming, The feed pressure of the hydrocyclone in the concentration operation is 0.16MPa, and the feed weight concentration is 20%; the weight concentration of the flotation pulp is 40%, and the flotation time is 10min. : sodium oleate=1:1, weight ratio), consumption is 1000g/t raw ore; Dispersant uses sodium carbonate, consumption is 2.0kg/t raw ore, obtains flotation concentrate. Other conditions are the same as Example 4, and the coarse-grained concentrate with an aluminum-silicon ratio of 9.17, a yield of 43.76%, and an Al ₂ O ₃ recovery rate of 47.48% can be obtained. The aluminum-silicon ratio of the mixed concentrate is 9.34, and the Al ₂ O ₃ recovery The rate is 88.20%.

Claims (5)

1, a kind of beneficiation method of middle-low bauxite, with middle low-grade diasporite bauxite is raw material, pulverize, it is characterized in that adopting the technological process of " the narrow rank flotation of selective milling---classification---desliming, concentrate---" to carry out ore dressing, its concrete processing step and technological parameter are as follows:

1), will pulverize raw material enters the selective milling operation, selective milling employing wet ball mill ore grinding or wet vibration mill ore grinding

Wet ball-milling, its spherical medium proportioning is Ф 30mm: Ф 20mm: Ф 15mm=30%: 50%: 20%, grinding medium filling ratio was 40%, and material ball ratio is 1.2, and rotational speed rate is 91%, ore grinding weight concentration 70%, ore grinding time 8min;

The wet vibration mill, its spherical medium proportioning is Ф 40mm: Ф 30mm: Ф 20mm=20%: 30%: 50%, amplitude 2.3mm, grinding medium filling ratio were 75%, and the ore grinding weight concentration is 70%, material ball ratio 0.9, the ore grinding time is 5min;

Two kinds of grinding modes all reach-200 orders and accounted for 48～55% o'clock at product granularity, put into graded operation,

2), classification, equipment is chosen hydrocyclone, its technological parameter is:

A, when adopting the wet ball mill ore grinding, control d ₅₀Be 0.11mm, the ore deposit pressure of giving of cyclone is 0.06～0.12MPa, gives ore deposit weight concentration 30～50%;

B, when above-mentioned operation adopts wet vibration mill ore grinding, control d ₅₀Be 0.080mm, cyclone give ore deposit pressure 0.1～0.15MPa, give ore deposit weight concentration 30～50%;

Coarse grain ore deposit after the separation and final concentrate merge, and overflow substance enters,

3), desliming, concentrate, the equipment choosing hydrocyclone, its technological parameter is:

Give ore deposit pressure 0.12～0.20MPa, give ore deposit weight concentration 10～30%; Overflow substance discharging through desliming, after concentrating, the sand setting after concentrating is put into,

4) narrow rank flotation, direct floatation process is adopted in flotation, ore pulp weight concentration 30～40%, flotation time 7～10min, floating agent and consumption are: collecting agent selected fatty acid class, consumption are 0.5～1.0kg/t raw ore; Dispersant is a sodium carbonate, and consumption is 1.5～2.0kg/t raw ore; The coarse-grain coarse ore concentrate that concentrate after the process flotation and graded operation obtain is merged into bulk concentrate product, tailings discharging.

2, according to the beneficiation method of the described middle-low bauxite of claim 1, when it is characterized in that adopting the ball mill ore grinding, mineral-feeding pipe diameter/overfall tube diameter=0.4～0.8 of the selected hydrocyclone of graded operation, overfall tube diameter/cyclone diameter=0.2～0.4, spigot diameter/overfall tube diameter=0.2～0.5, the cone angle of cyclone are 20 °; When above-mentioned operation adopts the vibromill ore grinding, mineral-feeding pipe diameter/overfall tube diameter=0.6～1.0 of the selected hydrocyclone of graded operation, overfall tube diameter/cyclone diameter=0.2～0.4, spigot diameter/overfall tube diameter=0.4～0.7, the cone angle of cyclone is 20 °.

3, according to the beneficiation method of the described middle-low bauxite of claim 1, it is characterized in that when desliming, when concentrating operation, mineral-feeding pipe diameter/overfall tube diameter=0.4～0.8 of selected hydrocyclone, overfall tube diameter/cyclone diameter=0.21～0.4, spigot diameter/overfall tube diameter=0.3～0.5, the cone angle of cyclone are 15 °.

4,, it is characterized in that the used collecting agent fatty acid of flotation is the confection of oxidized paraffin wax soap or enuatrol or oxidized paraffin wax soap and enuatrol according to the beneficiation method of the described middle-low bauxite of claim 1.

5, according to the beneficiation method of the described middle-low bauxite of claim 4, when it is characterized in that the used collecting agent of flotation is oxidized paraffin wax soap and enuatrol confection, its weight proportion oxidized paraffin wax soap: enuatrol=1: 1.