阅读说明：本技术 一种串联法两段分解生产氧化铝系统中去除草酸钠的方法 (Method for removing sodium oxalate in system for producing alumina by two-stage decomposition through series process ) 是由 王会兴 李志国 于 2020-06-04 设计创作，主要内容包括：本发明涉及一种去除草酸钠的方法,尤其涉及一种串联法两段分解生产氧化铝系统中去除草酸钠的方法。经过旋流器分级来的细种子浆液上料至过滤机进行分离,分离出的母液进入母液受液槽后再进入母液槽,用热水对分离出的细种子进行洗涤,洗涤后的洗液经洗液受液槽进入洗液槽,洗涤过的细种子进入滤饼槽,当洗液槽中洗液的草酸钠浓度积累到规定值之后,洗液送到浆化器与赤泥混合后进入赤泥槽搅拌成浆液,携带有草酸钠的赤泥浆液送去烧结法系统,草酸钠经过烧结即可分解消除。本发明优点效果：可以使洗液中草酸钠通过烧结的方式彻底地分解消除,进而逐步降低系统内草酸钠含量。草酸钠的消除作用直接、高效,经济、可行。(The invention relates to a method for removing sodium oxalate, in particular to a method for removing sodium oxalate in a system for producing alumina by two-stage decomposition in a series connection method. Feeding the fine seed slurry graded by the cyclone to a filter for separation, feeding the separated mother liquor into a mother liquor receiving tank and then into a mother liquor tank, washing the separated fine seeds with hot water, feeding the washed washing liquor into a washing liquor tank through the washing liquor receiving tank, feeding the washed fine seeds into a filter cake tank, feeding the washing liquor into a slurrying device after the concentration of sodium oxalate in the washing liquor tank is accumulated to a specified value, mixing the washing liquor with red mud, feeding the red mud slurry carrying the sodium oxalate into a sintering method system, and decomposing and eliminating the sodium oxalate through sintering. The invention has the advantages and effects that: the sodium oxalate in the washing liquid can be thoroughly decomposed and eliminated in a sintering mode, and the content of the sodium oxalate in the system is further gradually reduced. The elimination effect of sodium oxalate is direct, high-efficiency, economic and feasible.)

1. A method for removing sodium oxalate in a system for producing alumina by two-stage decomposition by a series method is characterized in that: feeding the fine seed slurry graded by the cyclone to a filter (1) for separation, feeding the separated mother liquor into a mother liquor receiving tank (3) and then into a mother liquor tank (6), washing the separated fine seeds with hot water, feeding the washed washing liquor into a washing liquor tank (7) through a washing liquor receiving tank (4), feeding the washed fine seeds into a filter cake tank (2), feeding the washing liquor into a pulp maker (11) after the concentration of sodium oxalate in the washing liquor tank (7) is accumulated to a specified value, mixing the washing liquor with red mud, feeding the mixture into a red mud tank (12) for stirring into slurry, feeding the red mud slurry carrying sodium oxalate into a sintering system, and decomposing and eliminating the sodium oxalate through sintering.

2. The method for removing sodium oxalate in the system for producing alumina by two-stage decomposition in series according to claim 1, wherein the filter (1) is a horizontal belt filter or a vertical disc filter.

3. The method for removing sodium oxalate in the system for producing alumina by two-stage decomposition in series connection according to claim 1, wherein the vacuum pump (5) provides the vacuum required for the operation of the filter (1), and the filtered mother liquor enters the mother liquor receiving tank (3), then enters the mother liquor tank (6), and the filtered washing liquor enters the washing liquor receiving tank (4), then enters the washing liquor tank (7).

4. The method for removing sodium oxalate in the system for producing alumina by two-stage decomposition in series connection according to claim 1, wherein the mother liquor entering the mother liquor tank (6) is sent to a mother liquor cooling process.

5. The method for removing sodium oxalate in the system for producing alumina by two-stage decomposition through a series process according to claim 1, wherein the washing of the separated fine seeds comprises 2-3 washing liquid circulation washing and the last hot water washing.

6. The method for removing sodium oxalate in the system for producing alumina by two-stage decomposition in series process according to claim 3, characterized in that the washing liquid is circularly washed, wherein the washing liquid entering the washing liquid tank (7) is returned to the filter (1) through the circulating washing liquid pump (8) to wash the fine seeds.

7. The method for removing sodium oxalate in the system for producing alumina by two-stage decomposition in series process according to claim 3, wherein the last hot water washing is to wash the fine seeds by adding new hot water at 85-95 ℃.

8. The method for removing sodium oxalate in the system for producing alumina by two-stage decomposition in series according to claim 1, wherein the fine seeds entering the filter cake tank (2) are mixed with the refined solution and then removed from the seed decomposition process.

9. The method for removing sodium oxalate in a series two-stage decomposition alumina production system according to claim 1, wherein the specified value of the accumulation of sodium oxalate concentration in the washing liquid is 2-10 g/L.

10. The method for removing sodium oxalate in a series two-stage decomposition system for producing alumina according to claim 1, wherein the fine seed washing liquid with the sodium oxalate concentration reaching the specified value in the washing liquid tank (7) is sent to the slurry device (11) through an external washing liquid pump (9); the Bayer process red mud enters a pulpifying device (11) after being subjected to filter pressing by a plate-and-frame filter press (10), is scattered by the pulpifying device (11) and is mixed with fine seed washing liquor, and the mixture enters a red mud tank (12).

11. The method for removing sodium oxalate in the system for producing alumina by two-stage decomposition in series process according to claim 1, wherein the red mud slurry carrying sodium oxalate is sent to the system of the sintering process by a red mud efflux pump (13).

12. A method for removing sodium oxalate in a system for producing alumina by two-stage decomposition by a series method is characterized in that: the fine seed slurry obtained through the classification of the cyclone is fed to a filter (1) for separation, the separated mother liquor enters a mother liquor receiving tank (3) and then enters a mother liquor tank (6), the separated fine seeds are washed by hot water, the washed washing liquor enters a washing liquor tank (7) through a washing liquor receiving tank (4), the washed fine seeds enter a filter cake tank (2), when the concentration of sodium oxalate in the washing liquor tank (7) is accumulated to a specified value, the washing liquor is directly sent to a sintering method system, and the sodium oxalate can be decomposed and eliminated through sintering.

Technical Field

The invention relates to a method for removing sodium oxalate, in particular to a method for removing sodium oxalate in a system for producing alumina by two-stage decomposition in a series connection method.

Background

China is the first major alumina producing country in the world, and the alumina yield is about 8000 million tons in 2018. With the less and less bauxite in China, the alumina enterprises in China import the gibbsite ore in foreign countries more and more. The gibbsite ore is generally decomposed by a low-temperature Bayer process and a two-stage decomposition process. Some enterprises containing sintering system can send the red mud after the gibbsite is dissolved out to sinter to form a series production system, and further recover the alumina remained in the red mud to increase economic benefit.

The gibbsite imported from abroad generally has the characteristic of high organic matter content, the organic matter can be gradually converted into sodium oxalate in the Bayer cycle process, and the sodium oxalate has a plurality of adverse effects on the working procedures of decomposition, evaporation and the like. In order to remove sodium oxalate in the system, some alumina enterprises adopt a method of causticizing fine seed washing liquor. The method can remove sodium oxalate in the system, but the causticization cost of the fine seed washing liquid is high, and the causticized slag is re-dissolved.

Disclosure of Invention

In order to solve the technical problem, the invention provides a method for removing sodium oxalate in a system for producing alumina by two-stage decomposition by a series process, aiming at removing the sodium oxalate in the system for producing alumina.

In order to achieve the purpose, the invention relates to a method for removing sodium oxalate in a series connection method two-stage decomposition production aluminum oxide system, wherein fine seed slurry obtained through classification of a cyclone is fed to a filter 1 for separation, the separated mother liquor enters a mother liquor receiving tank 3 and then enters a mother liquor tank 6, the separated fine seeds are washed by hot water, the washed washing liquor enters a washing tank 7 through a washing liquor receiving tank 4, the washed fine seeds enter a filter cake tank 2, after the concentration of sodium oxalate in the washing liquor in the washing tank 7 is accumulated to a specified value, the washing liquor is fed to a slurrying device 11 to be mixed with red mud and then enters a red mud tank 12 to be stirred into slurry, the red mud slurry carrying the sodium oxalate is fed to a sintering method system, and the sodium oxalate can be decomposed and eliminated through sintering.

The filter 1 is a horizontal belt filter or a vertical disc filter.

The vacuum pump 5 provides the vacuum required by the filter 1 to make the filtered mother liquor enter the mother liquor receiving tank 3 and then enter the mother liquor tank 6, and the filtered washing liquor enters the washing liquor receiving tank 4 and then enters the washing liquor tank 7.

And the mother liquor entering the mother liquor tank 6 is sent to a semen cooling process.

The washing of the separated fine seeds comprises 2-3 washing liquid circulation washing and the last hot water washing.

The washing liquid is circularly washed, namely, the washing liquid entering the washing liquid tank 7 is sent back to the filter 1 through the circulating washing liquid pump 8 to wash the fine seeds.

The last hot water washing is to newly add hot water with the temperature of 85-95 ℃ to wash the fine seeds.

And the fine seeds entering the filter cake tank 2 are mixed with the semen and then go to a seed decomposition process.

The specified value of the sodium oxalate concentration accumulation of the washing liquid is 2-10 g/L.

The fine seed washing liquid with the sodium oxalate concentration reaching the specified value in the washing liquid tank 7 is sent to a slurry device 11 through an external washing liquid pump 9; the Bayer process red mud is subjected to pressure filtration by a plate-and-frame filter press 10, enters a slurrying device 11, is scattered by the slurrying device 11 and is mixed with fine seed washing liquor, and the mixture enters a red mud tank 12.

The red mud slurry carrying sodium oxalate is sent to a sintering method system by a red mud efflux pump 13.

A method for removing sodium oxalate in a system for producing alumina by two-stage decomposition by a series method is characterized in that: feeding the fine seed slurry graded by the cyclone to a filter 1 for separation, feeding the separated mother liquor into a mother liquor receiving tank 3 and then into a mother liquor tank 6, washing the separated fine seeds with hot water, feeding the washed washing liquor into a washing liquor tank 7 through a washing liquor receiving tank 4, feeding the washed fine seeds into a filter cake tank 2, and when the concentration of sodium oxalate in the washing liquor tank 7 is accumulated to a specified value, feeding the washing liquor to a sintering method system, wherein the sodium oxalate can be decomposed and eliminated through sintering.

The invention has the advantages and effects that: the sodium oxalate in the washing liquid can be thoroughly decomposed and eliminated in a sintering mode, and the content of the sodium oxalate in the system is further gradually reduced. The elimination effect of sodium oxalate is direct, high-efficiency, economic and feasible.

Drawings

FIG. 1 is a flow chart of the system of the present invention.

In the figure: 1. a filter; 2. a filter cake tank; 3. a mother liquor receiving tank; 4. a washing liquid receiving tank; 5. a vacuum pump; 6. a mother liquor tank; 7. a washing solution tank; 8. circulating the washing liquid pump; 9. discharging a washing liquid pump; 10. a plate-and-frame filter press; 11. a slurrying device; 12. red mud tanks; 13. a red mud efflux pump.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Example 1

As shown in the figure, the method for removing sodium oxalate in the system for producing alumina by two-stage decomposition by a series connection method comprises the steps of feeding fine seed slurry graded by a cyclone into a filter 1 for separation, feeding the separated mother liquor into a mother liquor receiving tank 3 and then into a mother liquor tank 6, and sending the mother liquor entering the mother liquor tank 6 to a fine liquor cooling process; washing the separated fine seeds, and carrying out 3 times of washing liquid circulating washing and the last hot water washing, wherein the washing liquid circulating washing is that the washing liquid entering a washing liquid tank 7 is sent back to the filter 1 through a circulating washing liquid pump 8 to wash the fine seeds, and the last hot water washing is that the hot water at 90 ℃ is newly added to wash the fine seeds; the washed washing liquid enters a washing liquid tank 7 through a washing liquid receiving tank 4, the washed fine seeds enter a filter cake tank 2, and the fine seeds entering the filter cake tank 2 are mixed with the fine liquid and then go to a seed decomposition process; when the concentration of sodium oxalate in the washing liquid tank 7 is accumulated to a specified value, the washing liquid is sent to a slurrying device 11 through an external washing liquid pump 9, the specified value of the concentration of sodium oxalate is 2g/L, Bayer process red mud is subjected to pressure filtration through a plate-and-frame filter press 10 and then enters the slurrying device 11, the red mud is scattered by the slurrying device 11 and is mixed with fine seed washing liquid, then the mixture enters a red mud tank 12 and is stirred into slurry, the red mud slurry carrying the sodium oxalate is sent to a sintering process system through a red mud external pump 13, and the sodium oxalate can be decomposed and eliminated through sintering.

The filter 1 is a horizontal belt filter.

Example 2

As shown in the figure, the method for removing sodium oxalate in the system for producing alumina by two-stage decomposition by a series connection method comprises the steps of feeding fine seed slurry graded by a cyclone into a filter 1 for separation, feeding the separated mother liquor into a mother liquor receiving tank 3 and then into a mother liquor tank 6, and sending the mother liquor entering the mother liquor tank 6 to a fine liquor cooling process; washing the separated fine seeds, and carrying out washing liquid circulation washing for 2 times and hot water washing for the last time, wherein the washing liquid circulation washing is that the washing liquid entering a washing liquid tank 7 is sent back to the filter 1 through a circulation washing liquid pump 8 to wash the fine seeds, and the hot water washing for the last time is that hot water with the temperature of 85 ℃ is newly added to wash the fine seeds; the washed washing liquid enters a washing liquid tank 7 through a washing liquid receiving tank 4, the washed fine seeds enter a filter cake tank 2, and the fine seeds entering the filter cake tank 2 are mixed with the fine liquid and then go to a seed decomposition process; when the concentration of sodium oxalate in the washing liquid tank 7 is accumulated to a specified value, the washing liquid is sent to a slurrying device 11 through an external washing liquid pump 9, the specified value of the concentration of sodium oxalate is 10g/L, Bayer process red mud is subjected to pressure filtration through a plate-and-frame filter press 10 and then enters the slurrying device 11, the red mud is scattered by the slurrying device 11 and is mixed with fine seed washing liquid, then the mixture enters a red mud tank 12 and is stirred into slurry, the red mud slurry carrying the sodium oxalate is sent to a sintering process system through a red mud external pump 13, and the sodium oxalate can be decomposed and eliminated through sintering.

The filter 1 is a vertical disc filter.

Example 3

As shown in the figure, the method for removing sodium oxalate in the system for producing alumina by two-stage decomposition by a series connection method comprises the steps of feeding fine seed slurry graded by a cyclone into a filter 1 for separation, feeding the separated mother liquor into a mother liquor receiving tank 3 and then into a mother liquor tank 6, and sending the mother liquor entering the mother liquor tank 6 to a fine liquor cooling process; washing the separated fine seeds, and carrying out 3 times of washing liquid circulating washing and the last hot water washing, wherein the washing liquid circulating washing is that the washing liquid entering a washing liquid tank 7 is sent back to the filter 1 through a circulating washing liquid pump 8 to wash the fine seeds, and the last hot water washing is that the hot water at 95 ℃ is newly added to wash the fine seeds; the washed washing liquid enters a washing liquid tank 7 through a washing liquid receiving tank 4, the washed fine seeds enter a filter cake tank 2, and the fine seeds entering the filter cake tank 2 are mixed with the fine liquid and then go to a seed decomposition process; when the concentration of sodium oxalate in the washing liquid tank 7 is accumulated to a specified value, the washing liquid is discharged by an external washing liquid pump 9, the specified value of the concentration of the sodium oxalate is 5g/L, and when the plate-and-frame filter press 10 and the slurrying device 11 need to be stopped, the washing liquid is directly sent to a sintering method system, and the sodium oxalate can be decomposed and eliminated through sintering.

Although the embodiments of the present application have been described above with reference to the drawings, the present application is not limited to the above-mentioned embodiments, which are only illustrative and not restrictive, and those skilled in the art can make many forms without departing from the spirit and scope of the present application and the protection scope of the claims. .