US5084186A
Expired / Lapsed
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Sedimentation control process
Assignee: Individual
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Filing: 1990-06-19
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Granted: 1992-01-28
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Expires: 2010-06-19
Abstract
Abstract Sedimentation in an inherently colloidally stable mixture comprising a suspension of solids in a liquid is controlled by a five-step process. In the first step a mathematical model representing a relationship between certain parameters, namely area product, viscosity and a parameter related to zeta-potential, is created. In the second step, zones in the model in which there is undesirably high viscosity are identified, In the thrid step, a model sedimentation path which skirts the high viscosity zones is superimposed on the model. In the fourth step, the actual mixture under consideration is monitored during a sedimentation process to obtain actual measured values of any or all of the critical parameters. In the final step, the parameters are adjusted as necessary to fit actual measured values to values on the model sedimentation path.
Inventors
- 👤 Ian C. R. Gilchrist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:16
CPC Classifications
G; G05; G05D; G05D24/00; G05D24/02; B; B01; B01D; B01D21/00; B01D21/01; B01D21/30; B01D21/305; B01D21/32; B01D21/34; G01; G01N; G01N33/00; G01N33/0091
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
195 words
A process for preventing gel formation during sedimentation in an inherently colloidally-stable mixture comprising a suspension of solids in liquid, the process comprising the steps of: a) deriving a process model for the mixture representing a relationship between at least three parameters of the mixture, said at least three parameters including: a first parameter related to an area product of the mixture being representative of the total surface area of the particles per unit of volume of mixture, a second parameter representing a viscosity of the mixture, and a third parameter related to zeta-potential of solid particles in the mixture; b) identifying zones in the process model wherein the second parameter represents a viscosity such that spontaneous gelation is likely to take place; c) superimposing on the process model a model sedimentation path which avoids the zones where spontaneous gelation is likely to take place; d) monitoring the mixture to obtain actual values for the parameters during a sedimentation process; and e) adjusting the parameters of said mixture as necessary to fit the actual values to values on the model sedimentation path so that spontaneous gelation is avoided in said mixture during said sedimentation process.
Claim 2
Dependent Claim
195 words
A process for preventing gel formation during sedimentation in an inherently colloidally-stable mixture comprising a suspension of solids in liquid, the process comprising the steps of: a) deriving a process model for the mixture representing a relationship between at least three parameters of the mixture, said at least three parameters including: a first parameter related to an area product of the mixture being representative of the total surface area of the particles per unit of volume of mixture, a second parameter representing a viscosity of the mixture, and a third parameter related to zeta-potential of solid particles in the mixture; b) identifying zones in the process model wherein the second parameter represents a viscosity such that spontaneous gelation is likely to take place; c) superimposing on the process model a model sedimentation path which avoids the zones where spontaneous gelation is likely to take place; d) monitoring the mixture to obtain actual values for the parameters during a sedimentation process; and e) adjusting the parameters of said mixture as necessary to fit the actual values to values on the model sedimentation path so that spontaneous gelation is avoided in said mixture during said sedimentation process.
Claim 3
Dependent Claim
63 words
A process according to claim 1 wherein step c) of the process comprises superimposing on the process model a model sedimentation path of which certain sections represent equal turbidity of the mixture for varying values of the first, second and third parameters, and of which other sections represent constant area product of the mixture for varying values of the second and third parameters.
Claim 4
Dependent Claim
15 words
A process according to claim 1 wherein the third parameter is pH of the mixture.
Claim 5
Dependent Claim
84 words
A process according to claim 3 wherein step d) of the process comprises the steps of controlling the area product of the mixture by dilution with a diluent, increasing the pH of the mixture by adding an appropriate coagulating alkali, adding a flocculating agent to the mixture to cause flocculation of the mixture and sedimentation of solid flocs, and repeating any or all of these steps as necessary to fit the actual values obtained in step d) to values on the model sedimentation path.
Claim 6
Dependent Claim
11 words
A process according to claim 4 wherein the alkali is lime.
Claim 7
Dependent Claim
12 words
A process according to claim 4 wherein the diluent is clear water.
Claim 8
Dependent Claim
14 words
A process according to claim 4 wherein the flocculating agent is a polyacrylamide flocculant.
Claim 9
Dependent Claim
24 words
A process according to claim 1 wherein the third parameter is concentration in the mixture of an appropriate inorganic salt adapted to reduce zeta-potential.
Claim 10
Dependent Claim
83 words
A process according to claim 8 wherein step d) of the process comprises the steps of controlling the area product of the mixture by dilution with a diluent, reducing the zeta-potential of the mixture by adding the inorganic salt, adding a flocculating agent to the mixture to cause flocculation of the mixture and sedimentation of solid flocs, and repeating any or all of these steps as necessary to fit the actual values obtained in step d) to values on the model sedimentation path.
Claim 11
Dependent Claim
12 words
A process according to claim 9 wherein the diluent is clear water.
Claim 12
Dependent Claim
14 words
A process according to claim 9 wherein the flocculating agent is a polyacrylamide flocculant.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 1995-01-27 | 1995-07-29 | 1996-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-27 | 1999-07-29 | 2000-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-27 | 2003-07-29 | 2004-01-28 | $7700.00 | Window Closed / Lapsed |