CN103357507A - Lignite flotation method - Google Patents

Abstract

The invention provides a flotation method of lignite, which comprises the following steps: pyrolyzing lignite at low temperature to obtain upgraded coal; configuring upgraded coal into a pulp; pre-stirring, namely adding a collecting agent into the ore pulp; stirring, adding a foaming agent into the ore pulp, scraping bubbles, controlling the water supplementing speed while scraping bubbles to keep the liquid level of the ore pulp constant during the whole bubble scraping period, closing the flotation machine, stopping water supplementing, and performing suction filtration on clean coal and tailing coal to obtain a product. The lignite flotation method provided by the invention is scientific and reasonable in steps, overcomes the defects of the prior art, can conveniently and effectively realize lignite flotation, and effectively reduces ash content of upgraded coal.

Description

Lignite flotation method

technical field

The invention relates to coal cleaning technology, in particular to a lignite flotation method.

Background technique

my country is a country poor in oil, low in gas, and relatively rich in coal resources. Coal plays an extremely important role in my country's national economic and social development. In 2008, my country's coal output reached 2.793 billion tons. As China's basic energy, coal accounts for about 70% of primary energy. In the next 20 years, coal will still be the most important energy source in our country.

According to the volatile content of coal, China divides all coal into lignite, bituminous coal and anthracite. Among them, lignite resource reserves account for about 13% of my country's total coal reserves, mainly distributed in the three northeastern provinces, Inner Mongolia Autonomous Region and Yunnan Province. The efficient, clean and rational utilization of lignite resources has very important strategic significance for the sustainable development of our society and national economy.

Lignite has a low degree of deterioration and has the characteristics of low calorific value, high moisture, high ash content, and high volatile content. Its surface contains a large number of oxygen-containing functional groups, resulting in poor hydrophobicity and difficult flotation. There is an urgent need for a convenient and effective method for lignite flotation.

Contents of the invention

The object of the present invention is to propose a lignite flotation method for the current difficult problem of lignite flotation, so as to realize lignite flotation conveniently and effectively, and effectively reduce the ash content of upgraded coal.

In order to achieve the above object, the technical solution adopted in the present invention is: a lignite flotation method, comprising the following steps: pyrolyzing lignite at low temperature to obtain upgraded coal; configuring the upgraded coal into slurry; pre-stirring, adding Collector; Stir, then add foaming agent to the slurry, scrape foam, control the water replenishment speed at the same time, keep the slurry level constant during the whole scraping foam period, turn off the flotation machine, stop water replenishment, clean coal, tailings The coal is suction filtered to obtain the product.

Further, the low-temperature pyrolysis temperature of the lignite is 300°C-700°C.

Further, the upgraded coal is crushed to a particle size of less than 0.5 mm before being configured into a slurry.

Further, the concentration of upgraded coal in the slurry is 40g/L-140g/L.

Further, the collector is kerosene.

Further, the addition amount of the collector is 1.0-4.0kg/t.

Further, the foaming agent is secondary octanol.

Further, the added amount of the foaming agent is 0.231-1.389kg/t.

Further, adding a foaming agent, scraping after 5-30s, the scraping speed is 10-100r/min, and the scraping time is 2-10 minutes.

Further, the pre-stirring time is 1-5min.

The steps of the lignite flotation method of the present invention are scientific and reasonable, and compared with the prior art, it has the following advantages:

1) The content of oxygen-containing functional groups on the surface of the upgraded coal obtained by lignite pretreatment (pyrolysis) is reduced, the hydrophilicity is reduced, and the hydrophobicity is increased, which increases the floatability and facilitates the flotation of lignite.

2) The surface hydrophilic groups of the upgraded coal obtained from lignite pyrolysis are reduced, and the hydrophobicity is increased, which is conducive to the deashing of the upgraded coal, that is, the ash content of the upgraded coal can be effectively reduced by flotation, and the quality of the upgraded coal can be increased. The way of coal utilization is of great significance to realize the effective utilization of lignite.

In addition, the pyrolysis upgrading of lignite not only obtains upgraded coal with high calorific value, but also obtains high-value chemical raw materials-tar and gas that can be used as industrial or domestic fuel gas.

Detailed ways

The lignite (low-rank high-ash coal) flotation method of the present invention is a method for pretreating the lignite, obtaining upgraded coal through pyrolysis, and performing flotation on the upgraded coal. Specifically include the following steps:

1) Low-temperature pyrolysis of lignite to obtain upgraded coal, the surface hydrophilic groups of the pyrolyzed upgraded coal are reduced, and the hydrophobicity is increased, which is conducive to the deashing of the upgraded coal;

2) Configure the upgraded coal into slurry;

3) Pre-stirring, adding collector to the slurry;

4) Stir, then add a foaming agent to the pulp, scrape the foam, and control the water replenishment speed at the same time to keep the liquid level of the pulp constant during the foam scraping, turn off the flotation machine, and stop the water replenishment, clean coal and tailing coal The product was obtained by suction filtration.

The lignite is an upgraded coal obtained by low-temperature pyrolysis (thermal upgrading) at a temperature of 300°C-700°C. The upgraded coal is crushed to a particle size of less than 0.5mm before being configured into pulp. The concentration of upgraded coal in the slurry is 40g/L-140g/L, preferably 50g/L-100g/L.

The collector includes, but is not limited to, kerosene. The addition amount of the collector is 1.0-4.0kg/t, preferably 2.0-3.0kg/t.

The foaming agent includes but is not limited to 2-octyl alcohol, and it can be understood that other conventional foaming agents can also be used for scraping. The added amount of foaming agent in the present invention is 0.231-1.389kg/t, preferably 0.5-1.0kg/t. Add the foaming agent, after 5-30s (make the scraping agent fully mixed in the pulp), scrape, preferably after 10s, the scraping speed is 10-100r/min, preferably 30r/min, The scraping time is 2-10 minutes, preferably 3 minutes. The pre-stirring time is 1-5 min, preferably 2 min; the stirring time is 0.5-3 min, preferably 1 min.

In order to ensure the yield of flotation, after the flotation, the particles stuck on the wall of the flotation tank should be washed into the clean coal product. Clean coal and tailing coal are filtered to obtain products, and the product is placed in a constant temperature box; the ash content of clean coal and tailing coal is measured, and the yield, combustible body extraction rate and flotation perfection index are calculated.

The pretreatment of lignite by pyrolysis improves the comprehensive utilization value of lignite, and produces coal tar, upgraded coal and gas during the pyrolysis process. In addition, the coal tar and gas produced by the pretreatment of lignite by pyrolysis also have important economic value, among which coal tar is a high-value chemical raw material, which can be produced through deep processing to produce series of phenols, benzenes and naphthalenes, etc. Products, hydrogenation can produce naphtha, gasoline and diesel oil, etc. Coal gas can be used as industrial or civil fuel gas, and after conversion, desulfurization, decarbonization, pressure swing adsorption and other processes, hydrogen is produced and liquefied natural gas is produced as a by-product. Upgraded coal is a good solid clean fuel, which can be used for civil and industrial power generation, and can also be used for gas production to produce chemical products such as synthetic ammonia and methanol. The char slurry can also be used as a raw material for the production of activated carbon, etc.

Example 1

This embodiment discloses a lignite flotation method. Lignite from the Yuanbaoshan Mining Area in Chifeng City, Inner Mongolia is selected as a raw material, and conventional flotation equipment is used. The lignite flotation method described in this embodiment specifically includes the following steps:

First, the upgraded coal obtained by subjecting lignite to low-temperature pyrolysis (thermal upgrading) at 300°C has an ash content of 17.13%; after the upgraded coal is crushed to a particle size of less than 0.5mm, it is configured into The concentration of the pulp is 60g/L, the mixing speed of the pulp is 2100r/min, and the air volume is 300L/h. The collision between the upgraded coal particles and the air bubbles will make the upgraded coal particles adhere to the surface of the air bubbles in time and separate from the tailing coal or ash. separation;

Then, pre-stirring for 2min, adding kerosene to the slurry, the amount of kerosene added is 3.5kg/t;

Finally, stir for 1 min, then add 2-octanol to the pulp, the amount of 2-octanol added is 0.462kg/t, after 10s, scrape at a speed of 30r/min for 3min, and control the water replenishment speed at the same time, so that the entire scrape During this period, the liquid level of the ore slurry is constant; the flotation machine is turned off, and the water replenishment is stopped, the tailing coal is discharged into the enamel basin, and the particles sticking to the wall of the flotation tank are washed into the clean coal product; the clean coal and tailing coal are filtered to obtain the product , put the product in a constant temperature box; measure the ash content of clean coal and tailing coal, and calculate the yield, combustible body extraction rate and flotation perfection index.

Using this embodiment to carry out flotation on lignite, the resulting clean coal yield is 18.19%, the clean coal ash is 11.92%, the ash reduction rate is 30.38%, the combustible body extraction rate is 19.65%, and the flotation perfection index is 6.78%.

Example 2

This embodiment discloses a lignite flotation method. Lignite from the Yuanbaoshan mining area in Chifeng City, Inner Mongolia is selected as a raw material, and conventional flotation equipment is used. The lignite flotation method described in this embodiment specifically includes the following steps:

First, the upgraded coal obtained by subjecting lignite to low-temperature pyrolysis (thermal upgrading) at 400°C has an ash content of 18.87%; after the upgraded coal is crushed to a particle size of less than 0.5mm, it is configured into The concentration of the pulp is 60g/L, and the mixing speed of the configured pulp is: 2100r/min, and the aeration volume is 300L/h;

Then, pre-stirring for 2min, adding kerosene to the slurry, the amount of kerosene added is 3.5kg/t;

Finally, stir for 1 min, then add 2-octanol to the pulp, the amount of 2-octanol added is 0.462kg/t, after 10s, scrape at a speed of 30r/min for 3min, and control the water replenishment speed at the same time, so that the entire scrape During this period, the liquid level of the ore slurry is constant; the flotation machine is turned off, and the water replenishment is stopped, the tailing coal is discharged into the enamel basin, and the particles sticking to the wall of the flotation tank are washed into the clean coal product; the clean coal and tailing coal are filtered to obtain the product , put the product in a constant temperature box; measure the ash content of clean coal and tailing coal, and calculate the yield, combustible body extraction rate and flotation perfection index.

Using this embodiment to carry out flotation on lignite, the resulting clean coal yield is 30.56%, the clean coal ash is 11.78%, the ash reduction rate is 37.57%, the combustible body extraction rate is 33.23%, and the flotation perfection index is 14.15%.

Example 3

This embodiment discloses a lignite flotation method. Lignite from the Yuanbaoshan mining area in Chifeng City, Inner Mongolia is selected as a raw material, and conventional flotation equipment is used. The lignite flotation method described in this embodiment specifically includes the following steps:

First, the upgraded coal obtained by subjecting lignite to low-temperature pyrolysis (thermal upgrading) at 500°C has an ash content of 20.84%; after the upgraded coal is crushed to a particle size of less than 0.5mm, it is configured into The concentration of the pulp is 60g/L, and the mixing speed of the configured pulp is: 2100r/min, and the aeration volume is 300L/h;

Then, pre-stirring for 2min, adding kerosene to the slurry, the amount of kerosene added is 3.5kg/t;

Finally, stir for 1 min, then add 2-octanol to the pulp, the amount of 2-octanol added is 0.462kg/t, after 10s, scrape at a speed of 30r/min for 3min, and control the water replenishment speed at the same time, so that the entire scrape During this period, the liquid level of the ore slurry is constant; the flotation machine is turned off, and the water replenishment is stopped, the tailing coal is discharged into the enamel basin, and the particles sticking to the wall of the flotation tank are washed into the clean coal product; the clean coal and tailing coal are filtered to obtain the product , put the product in a constant temperature box; measure the ash content of clean coal and tailing coal, and calculate the yield, combustible body extraction rate and flotation perfection index.

Using this embodiment to carry out flotation on lignite, the yield of clean coal obtained is 80.14%, the ash fraction of clean coal is 12.87%, the ash reduction rate is 38.25%, the extraction rate of combustibles is 88.21%, and the flotation perfection index is 38.72%.

Example 4

This embodiment discloses a lignite flotation method. Lignite from the Yuanbaoshan mining area in Chifeng City, Inner Mongolia is selected as a raw material, and conventional flotation equipment is used. The lignite flotation method described in this embodiment specifically includes the following steps:

First, the upgraded coal obtained by subjecting lignite to low-temperature pyrolysis (thermal upgrading) at 600°C has an ash content of 23.00%; after the upgraded coal is crushed to a particle size of less than 0.5mm, it is configured into The concentration of the pulp is 60g/L, and the mixing speed of the configured pulp is: 2100r/min, and the aeration volume is 300L/h;

Then, pre-stirring for 2min, adding kerosene to the slurry, the amount of kerosene added is 3.5kg/t;

Finally, stir for 1 min, then add 2-octanol to the pulp, the amount of 2-octanol added is 0.462kg/t, after 10s, scrape at a speed of 30r/min for 3min, and control the water replenishment speed at the same time, so that the entire scrape During this period, the liquid level of the ore slurry is constant; the flotation machine is turned off, and the water replenishment is stopped, the tailing coal is discharged into the enamel basin, and the particles sticking to the wall of the flotation tank are washed into the clean coal product; the clean coal and tailing coal are filtered to obtain the product , put the product in a constant temperature box; measure the ash content of clean coal and tailing coal, and calculate the yield, combustible body extraction rate and flotation perfection index.

Using this embodiment to carry out flotation on lignite, the yield of clean coal obtained is 83.08%, the ash fraction of clean coal is 13.93%, the ash reduction rate is 39.43%, the extraction rate of combustibles is 92.86%, and the flotation perfection index is 42.54%.

Example 5

This embodiment discloses a lignite flotation method. Lignite from the Yuanbaoshan mining area in Chifeng City, Inner Mongolia is selected as a raw material, and conventional flotation equipment is used. The lignite flotation method described in this embodiment specifically includes the following steps:

First, the upgraded coal obtained by subjecting lignite to low-temperature pyrolysis (thermal upgrading) at 700°C has an ash content of 26.20%; after the upgraded coal is crushed to a particle size of less than 0.5mm, it is configured into The concentration of the pulp is 60g/L, and the mixing speed of the configured pulp is: 2100r/min, and the aeration volume is 300L/h;

Then, pre-stirring for 2min, adding kerosene to the slurry, the amount of kerosene added is 3.5kg/t;

Finally, stir for 1 min, then add 2-octanol to the pulp, the amount of 2-octanol added is 0.462kg/t, after 10s, scrape at a speed of 30r/min for 3min, and control the water replenishment speed at the same time, so that the entire scrape During this period, the liquid level of the ore slurry is constant; the flotation machine is turned off, and the water replenishment is stopped, the tailing coal is discharged into the enamel basin, and the particles sticking to the wall of the flotation tank are washed into the clean coal product; the clean coal and tailing coal are filtered to obtain the product , put the product in a constant temperature box; measure the ash content of clean coal and tailing coal, and calculate the yield, combustible body extraction rate and flotation perfection index.

Using this embodiment to carry out flotation of lignite, the yield of clean coal obtained is 72.81%, the ash fraction of clean coal is 16.09%, the ash reduction rate is 38.59%, the extraction rate of combustibles is 82.79%, and the flotation perfection index is 38.07%.

The present invention is not limited to the lignite flotation method described in the above examples, changes in the low-temperature pyrolysis temperature, types of collectors and frothers, and foam scraping conditions are all within the protection scope of the present invention.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope. the

Claims (10)

1. A method for flotation of lignite, characterized in that it comprises the steps of: obtaining upgraded coal by low-temperature pyrolysis of lignite; configuring the upgraded coal into slurry; pre-stirring, adding a collector to the slurry; stirring, and then Add a foaming agent to the pulp, scrape the foam, and control the water replenishment speed while scraping the foam, so that the liquid level of the pulp remains constant during the foam scraping period, turn off the flotation machine, stop the water replenishment, and filter the clean coal and tailing coal to obtain the product. 2. The method for flotation of lignite according to claim 1, characterized in that the low-temperature pyrolysis temperature of the lignite is 300°C-700°C. 3. The lignite flotation method according to claim 1 or 2, characterized in that the upgraded coal is crushed to a particle size of less than 0.5mm before being configured into pulp. 4. The method for flotation of lignite according to claim 1 or 2, characterized in that the concentration of upgraded coal in the slurry is 40g/L-140g/L. 5. the flotation method of lignite according to claim 1, is characterized in that, described collector is kerosene. 6. The method for flotation of lignite according to claim 1 or 5, characterized in that the amount of collector added is 1.0-4.0kg/t. 7. the flotation method of lignite according to claim 1, is characterized in that, described foaming agent is secondary octanol. 8. The lignite flotation method according to claim 1 or 7, characterized in that, the amount of the foaming agent added is 0.231-1.389kg/t. 9. the flotation method of lignite according to claim 1, is characterized in that, the described adding foaming agent, scraping foam is: add foaming agent, scrape foam after 5-30s, and described foaming speed is 10-100r /min, the scraping time is 2-10 minutes. 10. The flotation method of lignite according to claim 1, characterized in that, the pre-stirring time is 1-5min; the stirring time is 0.5-3min.