Title of Invention

INTEGRATED RED MUD SETTLING AND SEPARATING WASHING METHOD AND SETTLER

Abstract

The present invention discloses an integrated red mud settling and separating washing method and a settler, comprising the step of: settling the diluted slurry and separating sodium aluminate solution and the red mud therefrom, obtaining alumina product after the sodium aluminate solution goes through subsequent steps, settling and washing the red mud with hot water to remove soda contained therein, discharging the red mud to a red mud disposal dam after it reaches the emission standard, effecting settling and separating by using a flat bottomed settler, and effecting washing by hot water by using a highly effective settler. The present invention is constructed as comprising a flat bottomed settler and a highly effective settler, wherein a separating settler and a common settler are of flat bottomed settlers, and wherein several highly effective settlers are used as the washing settlers. The present invention sufficiently combines the advantages of the two prior art settlers so that a stable production is ensured, the red mud is discharged directly, thereby greatly reducing the production costs and ensuring an optimal effect in all respects of the whole production system.

Full Text

FPME05140053IN Description Integrated Red Mud Settling and Separating Washing Method and Settler Technical Field The present invention relates to a red mud settling and separating washing process and a tank in production of alumina. Background Art During production of alumina, the slurry, after being leached and then diluted, goes for settlement and separation through a settler such that the red mud and sodium aluminate solution are separated. Alumina product is obtained after the overflowing sodium aluminate solution goes through subsequent steps, the separated red mud is washed in a counter-current manner with hot water to reduce the soda content therein and, after reaching the emission standard, is discharged to a red mud disposal dam. The prior art red mud washing process is such that 3-5 washing settlers are used to wash the red mud, one or more separating settlers are used to separate the material, and meanwhile, to allow for cleansing and maintenance of the separating settlers or the washing settlers, one more settler is provided as a common settler that can be used as either a separating settler or a washing settler. Red mud settling and separating or washing apparatuses in the prior art are either a flat bottomed settler or a highly effective settler. A flat bottomed settler has a relatively large diameter, occupies a large area and correspondingly requires a great investment. It has advantages of a large volume, easy cleansing and a small amount of flocculant added (less than 25g/t dry red mud). Another advantage is that when a large fluctuation appears in production of alumina or material is discharged in the leaching step, a good buffering effect can be achieved by using said settler and a continuous and stable operation of the whole factory can be ensured. The shortcomings of said settler are long stay of materials, a great loss in hydrolization, and when the red mud is stacked by a dry method, a red mud filter is needed to conduct filtering and washing for one time such that the red mud can reach the emission standard. A highly effective settler has a smaller diameter, occupies a less area and correspondingly requires a smaller investment. The advantages thereof are a short stay of materials and a small loss in hydrolization, and the red mud after being washed is not filtered and washed but discharged directly so that a large number of operating staff is cut and operation cost is greatly reduced. The shortcomings of the settler resides in a small volume, a large amount of flocculant added (more than 50g/t dry red mud), and complicated manipulation and inspetion and maintenance, and what's more when a large fluctuation appears in production of alumina or material is discharged in the leaching step, a good buffering effect cannot be achieved by using said settler to ensure a continuous and stable operation of the production. Summary of the Invention An object of the present invention is to provide an integrated red mud settling and separating washing method that combines advantages of the above two kinds of settlers and that reduces loss in hydrolization of alumina, saves the red mud filtering step, save plenty of construction expenses, production and operation fees as well as manpower, and meanwhile ensures a continuous and stable operation of production. Another object of the present invention is to provide an integrated red mud settling, separating and washing tank, wherein the above two kinds of settlers are used to settle, separate and wash the slurry. The advantages of the above two settlers are combined to reach the foregoing object. The present invention is fulfilled by the steps of: settling the diluted slurry and separating sodium aluminate solution and the red mud therefrom, obtaining alumina product after the sodium aluminate solution goes through subsequent steps, settling and washing the red mud with hot water to remove soda contained therein, discharging the red mud to a red mud disposal dam after it reaches the emission standard, effecting settling and separating by using a flat bottomed settler, and effecting washing by hot water by using a highly effective settler. The present invention is constructed as comprising a flat bottomed settler and a highly effective settler, wherein a separating settler (1) and a common settler (2) are of flat bottomed settlers what are connected by a pipe, the common settler (2) is connected to a washing settler (3) by a pipe, and wherein several highly effective settlers are used as the washing settlers (3) that are connected by a pipe. Due to the above process, the present invention, as compared with the prior art, sufficiently combines the advantages of the two settlers so that a stable production is ensured, the red mud is discharged directly, the red mud filtering step by a red mud filter is saved, thereby greatly reducing the production costs and ensuring the whole production system reaches an optimal effect in construction and investment, operation and maintenance and stable production. Brief Introduction of Drawings Fig.l is a schematic view showing the procedures of the present invention. Preferred Embodiment According to one embodiment of the present invention, two flat bottomed settlers are used respectively as a separating settler (1) and a common settler (2), thereafter four highly effective settlers are connected as washing settlers (3), the leached slurry, after being diluted, goes into the separating settler (1) for separation, the overflowing sodium aluminate solution is sent to subsequent steps for processing, the red mud flowing from the bottom enters the washing settlers (3) for washing, the red mud after being washed is directly sent to a red mud disposal dam, and when the separating settler (1) or the washing settler (3) needs to be inspected and maintained, the common settler (2) is used to respectively replace them. Claims 1. An integrated red mud settling and separating washing method, comprising the steps of: settling the diluted slurry and separating sodium aluminate solution and the red mud therefrom, obtaining alumina product after the sodium aluminate solution goes through subsequent steps, settling and washing the red mud with hot water to remove soda contained therein, discharging the red mud to a red mud disposal dam after it reaches the emission standard, effecting settling and separating by using a flat bottomed settler, and effecting washing by hot water by using a highly effective settler. 2. A settler for implementing the integrated red mud settling and separating washing method as claimed in claim 1, comprising a flat bottomed settler and a highly effective settler, wherein a separating settler (1) and a common settler (2) are of flat bottomed settlers what are connected by a pipe, the common settler (2) is connected to a washing settler (3) by a pipe, and wherein several highly effective settlers are used as the washing settlers (3) that are connected by a pipe.

Documents:

1602-CHE-2005 AMENDED PAGES OF SPECIFICATION 05-09-2013.pdf

1602-CHE-2005 AMENDED CLAIMS 05-09-2013.pdf

1602-CHE-2005 CORRESPONDENCE OTHERS 05-09-2013.pdf

1602-CHE-2005 CORRESPONDENCE OTHERS 02-09-2013.pdf

1602-CHE-2005 CORRESPONDENCE OTHERS 16-08-2013.pdf

1602-CHE-2005 AMENDED CLAIMS 28-05-2012.pdf

1602-CHE-2005 AMENDED PAGES OF SPECIFICATION 28-05-2012.pdf

1602-CHE-2005 CORRESPONDENCE OTHERS 22-03-2012.pdf

1602-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 28-05-2012.pdf

1602-CHE-2005 FORM-3 28-05-2012.pdf

1602-CHE-2005 POWER OF ATTORNEY 28-05-2012.pdf

1602-che-2005-abstract.pdf

1602-che-2005-claims.pdf

1602-che-2005-correspondnece-others.pdf

1602-che-2005-description(complete).pdf

1602-che-2005-drawings.pdf

1602-che-2005-form 1.pdf

1602-che-2005-form 3.pdf

1602-che-2005-form 5.pdf

1602-che-2005-others.pdf