Title of Invention	PROCESS FOR TRANSPORTING AND FILTERING RED MUD
Abstract	This invention discloses a new process for transporting and filtering red mud in production of alumina. That is, the red mud slurry flowing from the bottom of a final washing settler tank in a settling workshop is transported by a multi-stage centrifugal pump system and a pipeline into the red mud slurry tank in a red mud stack yard. After some hot water is added to the red mud slurry tank, the red mud is seat by a pump into a red mud press filter for press filtering. The filter cakes obtained are transported by a motor vehicle to respective discharge points of the red mud stack yard. The red mud is stacked by dry method, The red mud washing water obtained after press filtering is returned to the settling procedure in the alumina factory for settling and washing of red mud. This invention comprehensively uses the advantages of wet transporting and dry stacking, so that the investment is economic; the use rate of the red mud stack yard is high; and it is favorable to environment protection.

Title of Invention

PROCESS FOR TRANSPORTING AND FILTERING RED MUD

Abstract

This invention discloses a new process for transporting and filtering red mud in production of alumina. That is, the red mud slurry flowing from the bottom of a final washing settler tank in a settling workshop is transported by a multi-stage centrifugal pump system and a pipeline into the red mud slurry tank in a red mud stack yard. After some hot water is added to the red mud slurry tank, the red mud is seat by a pump into a red mud press filter for press filtering. The filter cakes obtained are transported by a motor vehicle to respective discharge points of the red mud stack yard. The red mud is stacked by dry method, The red mud washing water obtained after press filtering is returned to the settling procedure in the alumina factory for settling and washing of red mud. This invention comprehensively uses the advantages of wet transporting and dry stacking, so that the investment is economic; the use rate of the red mud stack yard is high; and it is favorable to environment protection.

Full Text	New Process for Transporting and Filtering Red Mud Technical Field This invention relates to an alumina production process and, more particularly to a new process for transporting and filtering red mud in alumina refinery factories. Background Art At present, there are three solutions for transporting and stacking red mud in alumina factories. They have advantages and disadvantages, respectively. The actual states thereof are analyzed as follows. The solution of wet transporting and wet stacking of red mud is the most commonly used solution in alumina factories. After being washed in a settler tank, the red mud is sent to the red mud filtering procedure for wash filtering using a cylindrical filter and then sent into a red mud slurry tank. After the ratio of liquid to solid L/S indication is adjusted to about 3 to 4, the red mud is transported to a red mud stack yard by means of centrifugal pump and pipeline. This solution has the following characteristics. Namely, the ratio of liquid to solid L/S is high; the transporting resistance is small; the red mud can be transported by means of a multi-stage centrifugal pump system; and since centrifugal pumps belong to standard, conventional equipment, the investment is relatively low. This solution has the following disadvantages. Namely, the water content in the red mud is high, the red mud slurry volume is great; the red mud stack yard's volume to be taken is great; and since water takes considerable volume of the red mud stack yard, the use rate of the stack yard is low such that the investment in red mud stack yard is relatively great. In addition, it is more difficult to carry out anti-penetrating treatment to such red mud stack yard, which is adverse to environment protection. The solution of dry transporting and dry stacking of red mud is a relatively advanced solution for transporting and stacking of red mud that has been used by the alumina factories of our country in the recent ten years. After being washed in a settler tank, the red mud is sent to the red mud filtering procedure for wash filtering using a cylindrical filter and then sent into a red mud reaction tank for lowering the viscosity of the red mud by stirring shear to increase the flowability. A ratio of liquid to solid L/S of the red mud is adjusted to a range of 0.85 to 1.0 within the reaction tank. Then, the red mud is sent to a red mud stack yard by means of a high-pressure diaphragm pump and a pipeline. Wet stacking of red mud has many advantages. Firstly, the water content in the red mud is low, the volume is small, which occupies small volume in a red mud stack yard, such that the use rate of the red mud stack yard is high. Secondly, the red mud stack yard hardly contains water, which is very favorable to anti-penetrating and environment protection of the red mud stack yard. Thirdly, the red mud can be used to build red mud dam after it is dried, which can save building material, such that the operating cost of the red mud stack yard is relatively low. Fourthly, since water hardly accumulate in the red mud stack yard, the inner pressure of the red mud dam body is small, which is favorable to development of the red mud body to sky, such that the occupation of land will also be reduced. This solution has the following disadvantages. Namely, the viscosity of the red mud is relatively great after the ratio of liquid to solid L/S of the red mud slurry is reduced. The resistance of the pipeline is great when the red mud is transported. It usually requires the red mud pump to have a transportation pressure of 12,0 to 16,0 MPa during production. The conventional centrifugal pumps cannot satisfy said requirement. It needs to use imported high-pressure diaphragm pumps. The price of this kind of pumps is more than 5,000,000 yuan per set. An alumina factory in the scale of 400 kt/a is equipped with two sets of such pumps. The cost of buying the pumps needs more than 10,000,000 yuan. The solution of motor vehicle transporting and dry stacking is usually used in small-scale alumina factories. Since the quantity of red raud of the small-scale alumina factories is not great, the red mud transportation can be entrusted to an outside cooperation unit, thereby reducing one-time investment of building engineering. As far as large-scale alumina factories are concerned, however, this kind of transportation method has many disadvantages. Firstly, the labor intensity is high; the automaticity is low; and both loading and unloading are troublesome. Secondly, the operating cost is high, wherein the highway cost is relatively high besides the loading and unloading cost and transportation cost. Thirdly, if the motor vehicles cannot transport the red mud in time, it will possibly cause adverse effect on the production. Having studied the aforesaid three solutions for transporting and stacking red mud in details, this invention puts forward a new solution for transporting and stacking red mud directing to the shortages of the present solutions- Summary of the Invention The object of this invention is to put forward a new process for transporting and filtering red mud, which integrates the advantages of wet transporting and dry stacking of red mud to achieve the purpose of being economic in investment, having high use rate of red mud stack yard, and being favorable to environment protection, so as to solve the problems existing in the prior art. This invention is realized in the following manner: the red mud is transported by wet method and stacked by dry method, namely the red mud slurry flowing from the bottom of a final washing settler tank in a settling workshop is transported by a multi-stage centrifugal pump system and a pipeline into the red mud slurry tank in a red mud stack yard for proper diluting, and is then sent to a red mud press filter by a pump for press filtering; the red mud washing water obtained after press filtering is returned to the settling procedure in the alumina factory for settling and washing of red mud; and the filter cakes obtained by press filtering are transported by a motor vehicle to respective discharge points of the red mud stack yard. The red mud slurry flowing from the bottom of the final washing settler tank in the settling workshop has a ratio of liquid to solid controlled at 1. S to 2.5. Hot water is added to the red mud slurry tank to dilute the red mud. The water content in the red mud after it is filtered by means of a press filter is lower than 30%. The main content of this invention is as follows: (1) The red mud is transported by wet method, but the ratio of liquid to solid of the red mud is controlled at 1.5 to 2,5. The red mud is directly transported to the red mud stack yard after it flows out from the bottom of the present final washing settler tank without going through the red mud filtering procedure. (2) The red mud fihering procedure of the alumina factory is established beside the red mud stack yard. The stack yard is provided with several red mud slurry tanks into which the red mud slurry sent from the settling workshop enters. (3) The red mud is filtered by means of a press filter to make the water content of the red mud lower than 30% after it is filtered. (4) The red mud is transported to the stack yard by motor vehicles after it filtered. At present, no matter whether a flat bottom settler tank or a deep-cone high efficiency settler tank is used to treat the underflow of the final washing settler tank of the alumina factory, the ratio of liquid to solid L/S of the underflow can reach to L5 to 2.5. According the experience of alumina production, the slurry of this concentration can be easily transported by centrifugal pumps. To replace the high-pressure diaphragm pumps can reduce the investment in large amount- The purpose of providing red mud slurry tanks in the red mud stack yard is to perform the function of buffering storage so as to ensure stable feeding of the filter. To move the red mud filtering from the alumina factory to the ted mud stack yard and to replace the imported cylindrical filter with the press filter will not result in great change of investment. Besides, the water content of the filter cakes obtained from the press filter is even lower, usually below 30%. However, the water content of the red mud slurry transported to the red mud stack yard by dry method used in the present alumina factory is 46 to 48%. Therefore, the water content of this solution is even lower, which is more favorable to increase of the use rate of the red mud stack yard, anti-penetrating of the red mud, and environment protection. Since the red mud stack yard usually occupies great area of land, the red mud after being press filtered is transported by motor vehicles to respective stack points for the convenience of stacking. These motor vehicles only work within the range of the red mud stack yard and thus the transportation distance thereof is short. The main task thereof is transportation, which does not have the problem of increasing highway freight volume and paying highway fee. The beneficial effects of this invention are: comprehensively using the advantages of wet transporting and dry stacking of red mud, so that the investment is economic; the use rate of the red mud stack yard is high; and it is favorable to environment protection. Description of Figures Figure 1 is a schematic diagram of this invention. Mode of Carrying out the Invention Embodiment 1 of This Invention The red mud slurry flowong from the bottom of the final washing settler tank of a settling workshop has the ratio of liquid to solid L/S controlled at 1.5 to 2,5 and is sent by means of a multi-stage centrifugal pump system and a pipeline to the red mud slurry tank in the red mud stack yard. After the red mud is diluted by addition of some hot water to the red mud slurry tank, it is sent by means of a pump into a press filter for press filtering. The red mud washing water obtained after press filtering is returned to the settling procedure in the alumina factory for settling and washing of red mud. The filter cakes obtained has water content of lower than 30% and are transported to respective discharge points of the red mud stack yard by motor vehicles. Embodiment 2 of This Invention If the temperature of the red mud slurry flowmg from the bottom of the final washing settler tank in the settling workshop is on the low side, the viscosity will be caused to increase to affect the filter performance. A vapor tube can be added to the red mud slurry tank to heat the red mud slurry to raise the temperature and control the temperature at SO to 90 °C to ensure a good filter performance of the red mud slurry. The other aspects are the same as embodiment 1, We claim: 1. A new process for transporting and stacking red mud, characterized in that the red mud is transported by wet method and is stacked by dry method, namely the red mud slurry flowing from the bottom of a final washing settler tank in a settling workshop is transported into a red mud slurry tank in a red mud stack yard for proper diluting, and is then sent to a red mud press filter by a pump for press filtering; the red mud washing water obtained after press filtering is returned to the settling procedure in the alumina factory for settling and washing of red mud; and the filter cakes obtained by press filtering is transported by a motor vehicle to individual discharge points of the red mud stack yard. 2. A new process for transporting and stacking red mud according to claim 1, characterized in that the red mud slurry flowing from the bottom of the final washing settler tank of the settling workshop has a ratio of liquid to solid which is 1.5 to 2.5. 3. A new process for transporting and stacking red mud according to claim 1, characterised in that hot water is added to the red mud slurry tank to dilute the red mud.

Full Text

New Process for Transporting and Filtering Red Mud
Technical Field
This invention relates to an alumina production process and, more particularly to a new process for transporting and filtering red mud in alumina refinery factories.
Background Art
At present, there are three solutions for transporting and stacking red mud in alumina factories. They have advantages and disadvantages, respectively. The actual states thereof are analyzed as follows.
The solution of wet transporting and wet stacking of red mud is the most commonly used solution in alumina factories. After being washed in a settler tank, the red mud is sent to the red mud filtering procedure for wash filtering using a cylindrical filter and then sent into a red mud slurry tank. After the ratio of liquid to solid L/S indication is adjusted to about 3 to 4, the red mud is transported to a red mud stack yard by means of centrifugal pump and pipeline. This solution has the following characteristics. Namely, the ratio of liquid to solid L/S is high; the transporting resistance is small; the red mud can be transported by means of a multi-stage centrifugal pump system; and since centrifugal pumps belong to standard, conventional equipment, the investment is relatively low. This solution has the following disadvantages. Namely, the water content in the red mud is high, the red mud slurry volume is great; the red mud stack yard's volume to be taken is great; and since water takes considerable volume of the red mud stack yard, the use rate of the stack yard is low such that the investment in red mud stack yard is relatively great. In addition, it is more difficult to carry out anti-penetrating treatment to such red mud stack yard, which is adverse to environment protection.
The solution of dry transporting and dry stacking of red mud is a relatively advanced solution for transporting and stacking of red mud that has been used by the alumina factories of our country in the recent ten years. After being washed in a settler

tank, the red mud is sent to the red mud filtering procedure for wash filtering using a cylindrical filter and then sent into a red mud reaction tank for lowering the viscosity of the red mud by stirring shear to increase the flowability. A ratio of liquid to solid L/S of the red mud is adjusted to a range of 0.85 to 1.0 within the reaction tank. Then, the red mud is sent to a red mud stack yard by means of a high-pressure diaphragm pump and a pipeline. Wet stacking of red mud has many advantages. Firstly, the water content in the red mud is low, the volume is small, which occupies small volume in a red mud stack yard, such that the use rate of the red mud stack yard is high. Secondly, the red mud stack yard hardly contains water, which is very favorable to anti-penetrating and environment protection of the red mud stack yard. Thirdly, the red mud can be used to build red mud dam after it is dried, which can save building material, such that the operating cost of the red mud stack yard is relatively low. Fourthly, since water hardly accumulate in the red mud stack yard, the inner pressure of the red mud dam body is small, which is favorable to development of the red mud body to sky, such that the occupation of land will also be reduced. This solution has the following disadvantages. Namely, the viscosity of the red mud is relatively great after the ratio of liquid to solid L/S of the red mud slurry is reduced. The resistance of the pipeline is great when the red mud is transported. It usually requires the red mud pump to have a transportation pressure of 12,0 to 16,0 MPa during production. The conventional centrifugal pumps cannot satisfy said requirement. It needs to use imported high-pressure diaphragm pumps. The price of this kind of pumps is more than 5,000,000 yuan per set. An alumina factory in the scale of 400 kt/a is equipped with two sets of such pumps. The cost of buying the pumps needs more than 10,000,000 yuan.
The solution of motor vehicle transporting and dry stacking is usually used in small-scale alumina factories. Since the quantity of red raud of the small-scale alumina factories is not great, the red mud transportation can be entrusted to an outside cooperation unit, thereby reducing one-time investment of building engineering. As far as large-scale alumina factories are concerned, however, this kind of transportation method has many disadvantages. Firstly, the labor intensity is high;

the automaticity is low; and both loading and unloading are troublesome. Secondly, the operating cost is high, wherein the highway cost is relatively high besides the loading and unloading cost and transportation cost. Thirdly, if the motor vehicles cannot transport the red mud in time, it will possibly cause adverse effect on the production.
Having studied the aforesaid three solutions for transporting and stacking red mud in details, this invention puts forward a new solution for transporting and stacking red mud directing to the shortages of the present solutions-
Summary of the Invention
The object of this invention is to put forward a new process for transporting and filtering red mud, which integrates the advantages of wet transporting and dry stacking of red mud to achieve the purpose of being economic in investment, having high use rate of red mud stack yard, and being favorable to environment protection, so as to solve the problems existing in the prior art.
This invention is realized in the following manner: the red mud is transported by wet method and stacked by dry method, namely the red mud slurry flowing from the bottom of a final washing settler tank in a settling workshop is transported by a multi-stage centrifugal pump system and a pipeline into the red mud slurry tank in a red mud stack yard for proper diluting, and is then sent to a red mud press filter by a pump for press filtering; the red mud washing water obtained after press filtering is returned to the settling procedure in the alumina factory for settling and washing of red mud; and the filter cakes obtained by press filtering are transported by a motor vehicle to respective discharge points of the red mud stack yard.
The red mud slurry flowing from the bottom of the final washing settler tank in the settling workshop has a ratio of liquid to solid controlled at 1. S to 2.5. Hot water is added to the red mud slurry tank to dilute the red mud. The water content in the red mud after it is filtered by means of a press filter is lower than 30%.
The main content of this invention is as follows:
(1) The red mud is transported by wet method, but the ratio of liquid to solid of

the red mud is controlled at 1.5 to 2,5. The red mud is directly transported to the red mud stack yard after it flows out from the bottom of the present final washing settler tank without going through the red mud filtering procedure.
(2) The red mud fihering procedure of the alumina factory is established beside the red mud stack yard. The stack yard is provided with several red mud slurry tanks into which the red mud slurry sent from the settling workshop enters.
(3) The red mud is filtered by means of a press filter to make the water content of the red mud lower than 30% after it is filtered.
(4) The red mud is transported to the stack yard by motor vehicles after it
filtered.
At present, no matter whether a flat bottom settler tank or a deep-cone high efficiency settler tank is used to treat the underflow of the final washing settler tank of the alumina factory, the ratio of liquid to solid L/S of the underflow can reach to L5 to 2.5. According the experience of alumina production, the slurry of this concentration can be easily transported by centrifugal pumps. To replace the high-pressure diaphragm pumps can reduce the investment in large amount- The purpose of providing red mud slurry tanks in the red mud stack yard is to perform the function of buffering storage so as to ensure stable feeding of the filter.
To move the red mud filtering from the alumina factory to the ted mud stack yard and to replace the imported cylindrical filter with the press filter will not result in great change of investment. Besides, the water content of the filter cakes obtained from the press filter is even lower, usually below 30%. However, the water content of the red mud slurry transported to the red mud stack yard by dry method used in the present alumina factory is 46 to 48%. Therefore, the water content of this solution is even lower, which is more favorable to increase of the use rate of the red mud stack yard, anti-penetrating of the red mud, and environment protection.
Since the red mud stack yard usually occupies great area of land, the red mud after being press filtered is transported by motor vehicles to respective stack points for the convenience of stacking. These motor vehicles only work within the range of the red mud stack yard and thus the transportation distance thereof is short. The main task

thereof is transportation, which does not have the problem of increasing highway freight volume and paying highway fee.
The beneficial effects of this invention are: comprehensively using the advantages of wet transporting and dry stacking of red mud, so that the investment is economic; the use rate of the red mud stack yard is high; and it is favorable to environment protection.
Description of Figures
Figure 1 is a schematic diagram of this invention.
Mode of Carrying out the Invention
Embodiment 1 of This Invention
The red mud slurry flowong from the bottom of the final washing settler tank of a settling workshop has the ratio of liquid to solid L/S controlled at 1.5 to 2,5 and is sent by means of a multi-stage centrifugal pump system and a pipeline to the red mud slurry tank in the red mud stack yard. After the red mud is diluted by addition of some hot water to the red mud slurry tank, it is sent by means of a pump into a press filter for press filtering. The red mud washing water obtained after press filtering is returned to the settling procedure in the alumina factory for settling and washing of red mud. The filter cakes obtained has water content of lower than 30% and are transported to respective discharge points of the red mud stack yard by motor vehicles.
Embodiment 2 of This Invention
If the temperature of the red mud slurry flowmg from the bottom of the final washing settler tank in the settling workshop is on the low side, the viscosity will be caused to increase to affect the filter performance. A vapor tube can be added to the red mud slurry tank to heat the red mud slurry to raise the temperature and control the temperature at SO to 90 °C to ensure a good filter performance of the red mud slurry. The other aspects are the same as embodiment 1,

We claim:
1. A new process for transporting and stacking red mud, characterized in
that the red mud is transported by wet method and is stacked by dry method,
namely the red mud slurry flowing from the bottom of a final washing settler tank
in a settling workshop is transported into a red mud slurry tank in a red mud stack
yard for proper diluting, and is then sent to a red mud press filter by a pump for
press filtering; the red mud washing water obtained after press filtering is returned
to the settling procedure in the alumina factory for settling and washing of red
mud; and the filter cakes obtained by press filtering is transported by a motor
vehicle to individual discharge points of the red mud stack yard.
2. A new process for transporting and stacking red mud according to claim
1, characterized in that the red mud slurry flowing from the bottom of the final
washing settler tank of the settling workshop has a ratio of liquid to solid which is
1.5 to 2.5.
3. A new process for transporting and stacking red mud according to claim
1, characterised in that hot water is added to the red mud slurry tank to dilute the
red mud.

Documents:

266-CHENP-2008 EXAMINATION REPORT REPLY RECEIVED 16-05-2014.pdf

266-CHENP-2008 AMENDED CLAIMS 16-05-2014.pdf

266-CHENP-2008 AMENDED PAGES OF SPECIFICATION 16-05-2014.pdf

266-CHENP-2008 FORM-3 16-05-2014.pdf

266-CHENP-2008 AMENDED PAGES OF SPECIFICATION 01-09-2014.pdf

266-CHENP-2008 CORRESPONDENCE OTHERS 27-09-2013.pdf

266-CHENP-2008 CORRESPONDENCE OTHERS 29-05-2014.pdf

266-CHENP-2008 EXAMINATION REPORT REPLY RECIEVD 01-09-2014.pdf

266-CHENP-2008 FORM-1 01-09-2014.pdf

266-CHENP-2008 FORM-1 29-05-2014.pdf

266-CHENP-2008 OTHER PATENT DOCUMENT 29-05-2014.pdf

266-CHENP-2008 ENGLISH TRANSLATION 01-09-2014.pdf

266-chenp-2008-abstract.pdf

266-chenp-2008-claims.pdf

266-chenp-2008-correspondnece-others.pdf

266-chenp-2008-description(complete).pdf

266-chenp-2008-drawings.pdf

266-chenp-2008-form 1.pdf

266-chenp-2008-form 26.pdf

266-chenp-2008-form 3.pdf

266-chenp-2008-form 5.pdf

266-chenp-2008-pct.pdf

727-2008_Petiton 137 - POR.pdf

Petition for VET-PCT.pdf

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Patent Number

262713

Indian Patent Application Number

266/CHENP/2008

PG Journal Number

37/2014

Publication Date

12-Sep-2014

Grant Date

08-Sep-2014

Date of Filing

17-Jan-2008

Name of Patentee

CHINA ALUMINUM INTERNATIONAL ENGINEERING CORPORATION LIMITED

Applicant Address

B-15/F, TONGTAI MANSION, 33 JINRONG STREET, XICHENG DISTRICT, BEIJING 100032, CHINA.

Inventors:

#	Inventor's Name	Inventor's Address
1	CHEN, DE	208 BEIJING ROAD, GUIYANG CITY, GUIZHOU PROVINCE 550004, CHINA.

PCT International Classification Number

C02F 11/12

PCT International Application Number

PCT/CN2006/001740

PCT International Filing date

2006-07-18

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	200510200396.5	2005-07-18	China