CN115532410A - A method for removing iron and organic carbon in coal series kaolin - Google Patents

Abstract

The invention provides a method for removing iron and organic carbon in coal-series kaolin, and relates to the technical field of deep processing of coal-series kaolin. The method for removing iron and organic carbon in the coal-series kaolin comprises the steps of jaw crushing, coarse crushing, impact grinding, classification by a winnowing machine, magnetic substance separation and the like. The method disclosed by the invention is simple and easy to implement, has the advantages of few equipment, simple process, no need of adding water, no need of adding a chemical reagent and the like, can obviously improve the comprehensive utilization rate of the kaolin of the coal series, changes waste into valuable, saves energy, reduces emission, realizes green and environment-friendly exploitation and utilization of the kaolin, and finally has low iron and low iron contentThe yield of the COD kaolin concentrate is higher than 85 percent, and the content of Fe ₂ O ₃ The content is lower than 1 percent, the COD value is lower than 7000mg/kg, and the content indexes of the components all meet the application requirements of kaolin for glass fiber in industry.

Description

A method for removing iron and organic carbon in coal series kaolin

technical field

The invention relates to the technical field of deep processing of coal series kaolin, in particular to a method for removing iron and organic carbon in coal series kaolin.

Background technique

my country's coal-measure kaolin has the advantages of wide distribution, large reserves, and easy mining, and has high economic value. Coal series hard kaolin is mostly formed by sedimentation. Compared with soft kaolin, it has a single mineral composition, but generally contains a certain amount of organic carbon, and some also contain more pyrite, resulting in a darker color, generally light gray Gray, black and other colors seriously affect the quality of kaolin and limit its application in various aspects. Therefore, it is necessary to study the deep processing technology of coal series kaolin and improve its use value to meet the needs of the domestic market.

Generally speaking, organic carbon is usually associated with pyrite, and there is a certain density difference between kaolin and pyrite, so gravity separation is the most convenient and feasible physical method for iron removal and decarbonization. At present, the commonly used gravity separation methods include jigging separation, dense medium separation and wind separation. Among them, jigging separation is to use periodic pulsating water flow to make materials layered according to density on the bed, and the products after selection need to be dehydrated; heavy medium separation refers to separation in a medium with a density greater than water, often Magnetite powder is used as the aggravating substance, and the selected product needs to be decomposed and dehydrated, so a small amount of aggravating substance will inevitably be mixed into the sorted product, which will affect the whiteness and other properties of the product; The gravity separation method of the selection medium, the particles are layered and sorted according to the density under the action of their own gravity, wind force and mechanical force. The separation of materials with different densities can be realized by adjusting the wind force and mechanical force. The wind force separation process does not The participation of water and other media does not require dehydration and de-intermediation equipment. It has the characteristics of simple process, low investment, and quick results. The decarbonization and upgrading of coal gangue containing coal series kaolin by wind separation can benefit its more Well adapted to further calcination and deep processing.

Before the kaolin is sorted by air separator, it needs to be ultra-fine treatment. The traditional superfine pulverization process of hard coal series kaolin is to coarsely crush the raw ore and finely pulverize it by Raymond mill, and then produce superfine products with -10μm content of more than 85% by more than ten stages of wet superfine treatment. The use of impact mill can avoid the rough grinding process of Raymond mill, simplify the crushing process and improve the grinding efficiency, and the impact mill has the characteristics of low noise, less dust and high degree of automation, thus greatly improving the working conditions and helping to protect the environment. In addition, when the impact mill is used for kaolin crushing, the crushing force can be applied to the iron-containing ore particles, so that the impurity pyrite is exposed on the fracture surface, which is beneficial to the mineral processing and purification.

There are many methods for removing iron and carbon from coal-measure kaolin at present. Patent CN 201811549513.2 discloses a purification method of high-iron low-grade kaolin through the steps of pounding, fine classification, high-gradient magnetic separation, sedimentation separation, and stage-by-stage temperature-controlled bleaching to obtain Fe ₂ O ₃ content of less than 1.1%, whiteness Greater than 83% bleaching earth products. Patent CN201110371546.4 discloses a method for effectively reducing the COD of kaolin. Stir and mix kaolin with calcium hypochlorite and sodium peroxide, and add an appropriate amount of water to make it fully react. The sample obtained after the mixed reaction is low COD Agricultural kaolin. Patent CN 201610603695.1 discloses a method for removing iron in kaolin. Select kaolin with iron content below 0.8%, make pulp, add thiourea dioxide and oxalic acid, heat and stir, and press filter to obtain kaolin with iron content below 0.2%. . Patent CN 201911321733.4 discloses a kaolin iron removal process. The kaolin filter cake is put into a sulfuric acid pool, hydrogen peroxide and an appropriate amount of barium thiocyanate are added, filtered, dried, and powdered to obtain a finished product of kaolin after iron removal.

To sum up, at present, most of the iron and carbon in kaolin are removed by wet and chemical methods, but the wet and chemical methods are costly and not conducive to environmental protection. Therefore, increasing the research on the development of dry and physical methods to reduce iron and carbon in kaolin and realizing the high value-added utilization of kaolin is one of the important paths for coal-measure kaolin to turn waste into treasure, save energy and reduce emissions, and improve the green and environmentally friendly mining and utilization of kaolin. It is of great engineering significance to simultaneously remove iron and carbon from kaolin by dry method and physical method.

Contents of the invention

In order to solve the above problems, the present invention provides a method for removing iron and organic carbon in coal series kaolin, which includes the steps of jaw crushing coarse crushing, impact mill fine crushing, winnowing machine classification, magnetic material separation, etc., and finally obtains a _Fe2 Low iron and low COD kaolin concentrate with _O3 content less than 1% and COD value less than 7000mg/kg. The method for removing iron and organic carbon in coal series kaolin described in the present invention specifically comprises the following steps:

(1) Jaw Crushing Coarse Crushing: Put the raw ore of high-iron coal series kaolin into the jaw crusher for crushing to obtain coarse crushed particles;

(2) Impact mill fine crushing: the coarse crushed particles are ultra-finely crushed by the impact mill, and the ultra-fine powder is fed into the circular vibrating screen for screening, and the material on the screen is returned to the impact mill for further fine crushing, and the returned material that cannot be crushed is passed through slag discharge Mouth discharge;

In the crushing process of the present invention, the particle size of the product can be controlled by adjusting the working parameters of the impact mill to achieve ultra-fine effect;

(3) Air separation machine classification: the undersize with a particle size of <10 μm is selected by dry air selection to obtain heavy products and light products, the heavy products are discharged, and the light products fall into the electromagnetic net;

(4) Magnetic material separation: after the product passes through the electromagnetic net to remove iron, a low-iron and low-COD kaolin concentrate is obtained;

The magnetic substance in the material of the present invention mainly comes from the iron in the kaolin raw material and the iron oxide brought in some instruments and equipment. Therefore, the magnetic substance is separated from the material through the process of energizing the electromagnetic network and demagnetizing when the power is turned off, thereby further reducing the production capacity. The iron content can be obtained to obtain kaolin concentrate with low iron and low COD.

Further, the content of Fe ₂ O ₃ in the raw ore of high-iron coal series kaolin in the step (1) is 1wt%-5wt%, and the content of COD is 16000-30000mg/kg.

Further, in the step (1), the particle size of the discharge port of the jaw crusher is 2-3 cm, and the feed rate of the jaw crusher is 1 t/h.

Preferably, the model of the jaw crusher is PE500×750.

Further, in the step (1), the particle size of the coarsely crushed particles is <3cm.

Further, the rotational speed of the impact mill in the step (2) is 1300-1900 rpm, and the amount of returned material and slag discharged by the impact mill is ≤6%.

Preferably, the impact mill model is CM51.

Further, the particle size of the ultrafine powder in the step (2) is <10 μm.

Further, in the step (3), the heavy mineral slag discharged by the winnowing machine is ≤10%, and the frequency range of the winnowing machine is 14-22.25 Hz.

Preferably, the dry winnowing in the step (3) adopts a complete set of equipment, the model of which is GFX-25.

Further, in the step (4), a vibrating block is provided inside the conductive shaft of the electromagnetic grid, and the iron minerals on the electromagnetic grid can be shaken off and discharged when no power is applied.

Compared with prior art, beneficial technical effect of the present invention:

(1) The method for removing iron and organic carbon in coal-based kaolin of the present invention uses high-iron high-COD kaolin in the Enshi area of Hubei as a raw material, through steps such as jaw crusher coarse crushing, impact mill fine crushing, winnowing machine classification, magnetic material separation, etc., Simple and easy to implement, suitable for processing and purification of high-iron coal series kaolin raw ore, suitable for popularization and application;

(2) The output of the low-iron and low-COD kaolin concentrate of the present invention is higher than 85%, the _Fe2O3 content is lower than ₁ %, the COD value is lower than 7000mg/kg, and the component content indexes have all reached the application of kaolin for glass fiber in industry The tailings production is less than 15%, and the tailings can be transported to cement plants or ceramic factories for recycling, achieving zero emission and zero pollution;

(3) The present invention separates coal-based kaolin ore by dry method and physical method, not only can efficiently separate kaolin concentrate, but also has the advantages of less equipment, simple process, no need to add water, no need to add chemical reagents, etc. The process can significantly improve the comprehensive utilization rate of coal-based kaolin, turn waste into treasure, save energy and reduce emissions, and realize green and environmentally friendly mining and utilization of kaolin.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is a process flow chart of the method for removing iron and organic carbon in coal series kaolin according to the present invention.

detailed description

The invention provides a method for removing iron and organic carbon in coal series kaolin, which comprises the steps of jaw crushing coarse crushing, impact mill fine crushing, winnowing machine classification, magnetic material separation and the like, and finally obtains a Fe2O3 content of less than 1%. Low iron and low COD kaolin concentrate with COD value lower than 7000mg/kg. The method for removing iron and organic carbon in coal series kaolin described in the present invention specifically comprises the following steps:

(1) Jaw Crushing Coarse Crushing: Put the raw ore of high-iron coal series kaolin into the jaw crusher for crushing to obtain coarse crushed particles;

(2) Impact mill fine crushing: the coarse crushed particles are ultra-finely crushed by the impact mill, and the ultra-fine powder is fed into the circular vibrating screen for screening, and the material on the screen is returned to the impact mill for further fine crushing, and the returned material that cannot be crushed is passed through slag discharge Mouth discharge;

(3) Air separation machine classification: the undersize with a particle size of <10 μm is selected by dry air selection to obtain heavy products and light products, the heavy products are discharged, and the light products fall into the electromagnetic net;

(4) Magnetic material separation: After the product passes through the electromagnetic net to remove iron, a low-iron and low-COD kaolin concentrate is obtained.

In one embodiment, the content of Fe ₂ O ₃ in the high-iron coal series kaolin raw ore in the step (1) is 1wt%-5wt%, and the content of COD is 16000-30000mg/kg.

In one embodiment, in the step (1), the particle size at the outlet of the jaw crusher is 2-3 cm, and the feed rate of the jaw crusher is 1 t/h.

In one embodiment, the particle diameter of the coarsely ground particles in the step (1) is <3 cm.

In one embodiment, the rotational speed of the impact mill in the step (2) is 1300-1900 rpm, and the amount of returned material and slag discharged by the impact mill is ≤6%.

In one embodiment, the circular vibrating sieve in the step (2) is a -10 μm circular vibrating sieve.

In one embodiment, the particle size of the ultrafine powder in step (2) is <10 μm.

In one embodiment, in the step (3), the heavy mineral slag discharge of the winnowing machine is ≤10%, and the frequency range of the winnowing machine is 14-22.25 Hz.

In one embodiment, in the step (4), a vibrating block is arranged inside the conductive shaft of the electromagnetic grid, and the iron minerals on the electromagnetic grid can be shaken off the row iron when no power is applied.

The technical solution provided by the present invention will be further described below in conjunction with the examples.

Example 1

A method for removing iron and organic carbon in coal series kaolin, the steps are as follows:

(1) Jaw Crusher Coarse Crushing: Put coal series kaolin raw ore with iron content of 1.49% and COD value of 11494mg/kg directly into PE500×750 jaw crusher, set the particle size of the discharge port to 3cm, and obtain a particle size of less than 3cm of coarsely crushed particles;

(2) Shock mill fine crushing: the coarse crushed particles are passed through the feeder, the feeding speed is set to 1t/h, and the CM51 impact mill is fed into the ultrafine crushing, the impact mill speed is 1500rpm, and the -10μm reaches 86%. Ultrafine powder, the ultrafine powder is fed into the -10μm circular vibrating sieve through the belt conveyor, and the sieve with a particle size > 10μm is returned to the impact mill for further fine crushing. About 5% of the returned material that cannot be broken is about 5%. Slag port discharge;

(3) Air separation machine classification: the undersize with a particle size of <10 μm is fed into the GFX-25 dry air separation complete equipment through a belt conveyor, and the frequency of the air separation machine is set to 20.25 Hz, and the heavy product and Light products, heavy products with a mass of 9%, are discharged through the slag discharge port, and light products fall into the electromagnetic net through the screw conveyor;

(4) Separation of magnetic substances: Before the final product is packaged, iron is removed through an electromagnetic grid. The main source of magnetic substances is not only iron in kaolin raw materials, but also iron oxides brought out from some instruments and equipment. Magnetization, power failure and loss of magnetism, after magnetic material separation, further reduce the iron content in the product, and obtain kaolin concentrate with low iron and low COD.

Example 2

A method for removing iron and organic carbon in coal series kaolin, the steps are as follows:

(1) Jaw Crusher Coarse Crushing: Put coal series kaolin raw ore with iron content of 1.66% and COD value of 17430mg/kg directly into PE500×750 jaw crusher, set the particle size of the discharge port to 3cm, and obtain a particle size of less than 3cm of coarsely crushed particles;

(2) Shock mill finely crushing: Pass the coarsely crushed particles through the feeder, set the feeding speed to 1t/h, feed into the CM51 impact mill for ultrafine crushing, the impact mill speed is 1800rpm, and obtain -10μm up to 88% Ultrafine powder, the ultrafine powder is fed into the -10μm circular vibrating sieve through the belt conveyor, and the sieve with a particle size > 10μm is returned to the impact mill for further fine crushing, and the returned material that cannot be broken is about 6%. Slag port discharge;

(3) Classification by wind separator: feed the undersize with a particle size of <10 μm into the GFX-25 dry air separation complete equipment through a belt conveyor, set the frequency of the air separator to 22.25Hz, and obtain heavy products and Light products, heavy products with a mass of 6%, are discharged through the slag discharge port, and light products fall into the electromagnetic net through the screw conveyor;

(4) Separation of magnetic substances: Before the final product is packaged, iron is removed through an electromagnetic grid. The main source of magnetic substances is not only iron in kaolin raw materials, but also iron oxides brought out from some instruments and equipment. Magnetization, power failure and loss of magnetism, after magnetic material separation, further reduce the iron content in the product, and obtain kaolin concentrate with low iron and low COD.

Example 3

A method for removing iron and organic carbon in coal series kaolin, the steps are as follows:

(1) Jaw Crusher Coarse Crushing: Put coal series kaolin raw ore with iron content of 1.79% and COD value of 12959mg/kg directly into PE500×750 jaw crusher, set the particle size of the discharge port to 2cm, and obtain a particle size of less than 2cm of coarsely crushed particles;

(2) Impact mill finely crushing: the coarse crushed particles are passed through the feeder, the feeding speed is set to be 1t/h, and the CM51 type impact mill is fed into the ultrafine grinding, and the impact mill speed is 1600rpm, and the -10 μm reaches 85%. Ultra-fine powder, the ultra-fine powder is fed into the -10μm circular vibrating sieve through the belt conveyor, and the sieve with a particle size > 10μm is returned to the impact mill for further fine crushing. Mouth discharge;

(3) Air separator classification: feed the undersize with a particle size of <10 μm to the GFX-25 dry air separation equipment through a belt conveyor, and set the frequency of the air separator to 18 Hz to obtain heavy products and light products. The product, the weight of the heavy product is 9%, is discharged through the slag discharge port, and the light product falls into the electromagnetic net through the screw conveyor;

(4) Separation of magnetic substances: Before the final product is packaged, iron is removed through an electromagnetic grid. The main source of magnetic substances is not only iron in kaolin raw materials, but also iron oxides brought out from some instruments and equipment. Magnetization, power failure and loss of magnetism, after magnetic material separation, further reduce the iron content in the product, and obtain kaolin concentrate with low iron and low COD.

Example 4

A method for removing iron and organic carbon in coal series kaolin, the steps are as follows:

(1) Jaw Crusher Coarse Crushing: Put coal series kaolin raw ore with iron content of 1.71% and COD value of 14504mg/kg directly into PE500×750 jaw crusher, set the particle size of the discharge port to 2cm, and obtain a particle size of less than 2cm of coarsely crushed particles;

(2) Impact mill finely crushing: the coarsely crushed particles are passed through the feeder, the feeding speed is set to 1t/h, and the CM51 type impact mill is fed into the ultrafine grinding, the impact mill speed is 1700rpm, and the -10μm reaches 86%. Ultrafine powder, the ultrafine powder is fed into the -10μm circular vibrating sieve through the belt conveyor, and the sieve with a particle size > 10μm is returned to the impact mill for further fine crushing. Mouth discharge;

(3) Air separator classification: feed the undersize material with a particle size of <10 μm into the GFX-25 dry air separation equipment through a belt conveyor, and set the frequency of the air separator to 17 Hz to obtain heavy products and light products. Products, heavy products with a mass of 10%, are discharged through the slag discharge port, and light products fall into the electromagnetic net through the screw conveyor;

(4) Separation of magnetic substances: Before the final product is packaged, iron is removed through an electromagnetic grid. The main source of magnetic substances is not only iron in kaolin raw materials, but also iron oxides brought out from some instruments and equipment. Magnetization, power failure and loss of magnetism, after magnetic material separation, further reduce the iron content in the product, and obtain kaolin concentrate with low iron and low COD.

test case 1

The iron content and the COD value in the kaolin concentrate that embodiment 1-4 obtains and waste residue are measured, and the results are as follows:

It can be seen from the above table that the _Fe2O3 content in the kaolin concentrate obtained in Examples 1-4 _of the present invention is lower than 1wt%, the COD value is lower than 7000mg/kg, and the component content indicators have reached the industrial application of kaolin for glass fiber requirements.

In this paper, specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the present invention Thoughts, there will be changes in specific implementation methods and application ranges. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims (8)

1. A method for removing iron and organic carbon in coal-series kaolin is characterized by comprising the following steps:

(1) Crushing jaw and coarse crushing: putting the high-iron coal series kaolin crude ore into a jaw crusher to be crushed to obtain coarse crushed particles;

(2) Impact grinding and fine crushing: ultrafine grinding the coarse crushed particles by adopting an impact mill, feeding the ultrafine powder into a circular vibrating screen for screening, returning oversize materials to the impact mill for further fine crushing, and discharging return materials which cannot be crushed through a slag discharge port;

(3) Grading by a winnowing machine: dry winnowing the undersize product with the particle size less than 10 μm to obtain a heavy product and a light product, discharging the heavy product, and dropping the light product into an electromagnetic net;

(4) Magnetic substance separation: and (3) removing iron from the product by an electromagnetic net to obtain the kaolin concentrate with low iron and low COD.

2. The method for removing iron and organic carbon in coal-series kaolin according to claim 1, wherein Fe in the high-iron coal-series kaolin crude ore in the step (1) ₂ O ₃ The content of the COD is 16000-30000 mg/kg, and the content of the COD is 1-5 wt%.

3. The method for removing iron and organic carbon from coal-series kaolin as claimed in claim 1, wherein the grain size of the discharge port of the jaw crusher in the step (1) is 2-3 cm, and the feeding amount of the jaw crusher is 1t/h.

4. The method for removing iron and organic carbon from coal-series kaolin according to claim 1, wherein the particle size of the coarse particles in step (1) is less than 3cm.

5. The method for removing iron and organic carbon from coal-based kaolin as claimed in claim 1, wherein the rotational speed of the impact mill in the step (2) is 1300-1900 rpm, and the slag discharge amount of the returned material of the impact mill is less than or equal to 6%.

6. The method for removing iron and organic carbon from coal-based kaolin as claimed in claim 1, wherein the particle size of the ultrafine powder in step (2) is less than 10 μm.

7. The method for removing iron and organic carbon from coal-series kaolin as claimed in claim 1, wherein the deslagging amount of heavy minerals of the air separator in the step (3) is less than or equal to 10%, and the frequency range of the air separator is 14-22.25 Hz.

8. The method for removing iron and organic carbon from coal-series kaolin as claimed in claim 1, wherein in the step (4), a vibrating block is arranged in the conductive shaft of the electromagnetic screen, so that iron minerals on the electromagnetic screen can be shaken off to remove iron under the condition of no power supply.

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