# US 2014/0150886 A1 · Two-stage flocculation of fluid fine tailings > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0150886 A1 - Document ID: US20140150886A1 - Status: Published application - Kind: A1 - Application number: 14/093,020 - Filed: 2013-11-28 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Total E&P Canada Ltd. - Applicants: Total E&P Canada Ltd. - Inventors: Jianmin KAN; Alexandre GOLDSZAL - Web page: https://patentgrep.com/patent/US20140150886A1 ## CPC - F17D 1/088: {for solids or suspensions of solids in liquids, e.g. slurries (F17D1/086 takes precedence)} - B09B 1/00: Dumping solid waste - Y10T 137/0391: Affecting flow by the addition of material or energy - Y10T 137/2931: Diverse fluid containing pressure systems - F17D: PIPE-LINE SYSTEMS; PIPE-LINES (pumps or compressors F04; fluid dynamics F15D; valves or the like F16K; pipes, laying pipes, supports, joints, branches, repairing, work on the entire line, accessories F16L; steam traps or the like F16T; fluid-pressure electric cables H01B9/06) - B09B: DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method for treating and disposal of fluid fine tailings utilizes two stages of thickening prior to disposal of the thickened tailings. The fluid fine tailings are adjusted to a sand-to-fines ratio of 0.5 to 1.3 using hydrocyclones or centrifuges in required. In a first stage of thickening a first flocculant is added to the fluid fine tailings which are fed to one or more conventional thickeners to produce a pumpable thickened tailings underflow having a solids content of between about 20 wt % to 40 wt %. The pumpable thickened tailings underflow is centrifugally pumped through a pipeline towards a disposal area. Adjacent the disposal area a second flocculant is added to the pumpable tailings underflow in a second stage of thickening to flocculate the tailings sufficient to produce a secondary thickened tailings underflow which when deposited has a solids content of about 50 wt % or higher at least one day after disposal. Alternatively, the second flocculant can be added prior to a paste thickener located adjacent the disposal area to further thicken the secondary thickened tailings underflow to a solids content of about 65 wt % for direct disposal at the disposal area. ## Claims ### Claim 1 A method for treating and disposing of fluid fine tailings having a sand-to-fine solids ratio (SFR) between about 0.5 to about 1.3 comprising: in a first stage of thickening, adding an amount of a first flocculant to the fluid fine tailings for forming a thickener feedstream; and feeding the thickener feedstream to at least one thickener for producing a pumpable, first thickened tailings underflow; and pumping the first thickened tailings underflow to flow in a pipeline toward at least one disposal area; and in a second stage of thickening, adding an amount of a second flocculant to the first thickened tailings underflow flowing through the pipeline for producing a secondary thickened tailings underflow for disposal at the at least one disposal area. ### Claim 2 (depends on 1) The method of claim 1 further comprising: depositing the secondary thickened tailings underflow at the at least one disposal area, wherein, when deposited, dewatering and thickening occurs to a solids content therein of at least about 50 wt % or greater after about one day following the depositing. ### Claim 3 (depends on 1) The method of claim 1 wherein the pumpable first thickened tailings underflow has a solids content of between about 20 wt % to about 40 wt % and a yield stress of less than about 20 Pa. ### Claim 4 (depends on 1) The method of claim 1 further comprising: adding the amount of the second flocculant to the pumpable, first thickened tailings underflow flowing through the pipeline at a location adjacent the disposal area. ### Claim 5 (depends on 1) The method of claim 1 further comprising: adding the amount of the second flocculant to the pumpable first thickened tailings underflow flowing through the pipeline at an addition point about one hundred meters from the disposal area. ### Claim 6 (depends on 1) The method of claim 1 further comprising: mixing the second flocculant with the pumpable first thickened tailings underflow flowing in the pipeline using a mixer located in a terminal portion of the pipeline between the addition point and the disposal area. ### Claim 7 (depends on 6) The method of claim 6 further comprising: adjusting a length and a diameter of the terminal portion of the pipeline to control residence time and turbulence for mixing and effectively flocculating the pumpable first thickened tailings underflow therein for forming the secondary thickened tailings underflow. ### Claim 8 (depends on 1) The method of claim 1 wherein the first and second flocculants are anionic flocculants or cationic flocculants. ### Claim 9 (depends on 1) The method of claim 1 wherein the first and second flocculants are the same flocculant. ### Claim 10 (depends on 1) The method of claim 1 wherein the first and second flocculants are different flocculants. ### Claim 11 (depends on 1) The method of claim 1 wherein when the SFR is about 0.8, the amount of the first flocculant is from about 100 g/t to about 150 g/t. ### Claim 12 (depends on 1) The method of claim 1 wherein when the SFR is about 0.8, the amount of the first flocculant is from about 100 g/t to about 150 g/t. ### Claim 13 (depends on 1) The method of claim 1 wherein when the SFR is about 0.8, the amount of the second flocculant is from about 50 g/t to about 100 g/t. ### Claim 14 (depends on 1) The method of claim 1 further comprises: receiving the pumpable first thickened tailings underflow, after the addition of the second flocculant, at a paste thickener located at or adjacent the disposal area; and thickening the first thickened tailings underflow in the paste thickener for producing the secondary thickened tailings underflow therein having a solids content of at least about 65 wt % for disposal at the disposal area. ### Claim 15 (depends on 1) The method of claim 1, prior to the adding of the first flocculant, further comprising: adjusting a sand-to-fine solids ratio (SFR) of extraction tailings to between about 0.5 to about 1.3. ### Claim 16 (depends on 15) The method of claim 15 wherein the adjusting the SFR comprises: treating the extraction tailings using centrifugal classification for removal of coarse tailings therefrom. ### Claim 17 (depends on 15) The method of claim 15 wherein the adjusting the SFR comprises: proportionally mixing the extraction tailings with coarse tailings. ### Claim 18 (depends on 1) The method of claim 1 further comprising: pumping the pumpable thickener underflow using a centrifugal pump. ### Claim 19 A system for treatment and disposal of fluid fine tailings having a sand-to-fine solids ratio (SFR) between about 0.5 to about 1.3 comprising: in a first stage of thickening, at least one thickener for receiving flocculated fluid fine tailings, an amount of a first flocculant having been added to the fluid fine tailings for producing a pumpable first thickened tailings underflow; a pipeline connected between the at least one thickener and at least one disposal area one or more pumps for pumping the pumpable pumpable first thickened tailings underflow to flow through the pipeline from the at least one thickener to the at least one disposal site; and in a second stage of thickening, a point of addition in the pipeline adjacent the at least one disposal site for adding an amount of a second flocculant to the pumpable first thickened tailings underflow flowing through the pipeline to produce a secondary thickened tailings underflow, wherein the amount of the second flocculant causes the secondary thickened tailings underflow, when deposited at the at least one disposal area, to dewater and further thicken to a solids content therein of at least about 50 wt % or greater after about one day following depositing. ### Claim 20 (depends on 19) The system of claim 19 wherein the pumpable, first thickened tailings underflow from the at least one thickener has a solids content of about 20 wt % to about 40 wt %. ### Claim 21 (depends on 19) The system of claim 19 further comprising: a paste thickener positioned adjacent the disposal area for receiving the secondary thickened tailings underflow for thickening therein to a solids content of at least about 65 wt % for disposal at the disposal area. ### Claim 22 (depends on 19) The system of claim 19 wherein, when the SFR is about 0.8, the amount of the first flocculant is about 100 g/t to about 150 g/t and the amount of the second flocculant is about 50 g/t to about 100 g/t. ### Claim 23 (depends on 19) The system of claim 19 further comprising a mixer positioned in the pipeline following the point of addition of the second flocculant. ### Claim 24 (depends on 19) The system of claim 19 further comprising apparatus for centrifugal classification of extraction tailings for adjusting a sand-to-fine solids ratio (SFR) to between about 0.5 to about 1.3.