Concentration of suspensions

Patent metadata

Field	Value
Publication number	US-2016082367-A1
Application number	US-201414787119-A
Country	US
Kind code	A1
Filing date	Apr 22, 2014
Priority date	Apr 26, 2013
Publication date	Mar 24, 2016
Grant date	—

Abstract

A process of concentrating an aqueous suspension of solid particles, comprising the steps of introducing the aqueous suspension of solid particles into a vessel, addition of at least one organic polymeric flocculant to the aqueous suspension of solid particles thereby forming flocculated solids, allowing the flocculated solids to settle to form a compression zone, comprising a bed of sedimented solids in suspension at the lower end of the vessel, flowing the sedimented solids from the vessel as an underflow stream, in which an effective amount of ultrasonic energy is applied to: a) the bed of solids at the compression zone; b) the sedimented solids in the underflow stream; or c) a recycle stream containing sedimented solids taken from either the underflow stream or the compression zone which are then recycled back to the vessel.

First claim

1 . A process of concentrating an aqueous suspension of solid particles, comprising:
introducing the aqueous suspension of solid particles into a vessel, adding at least one organic polymeric flocculant to the aqueous suspension of solid particles thereby forming flocculated solids, allowing the flocculated solids to settle to form a compression zone, comprising a bed of sedimented solids in suspension at the lower end of the vessel, flowing the sedimented solids from the vessel as an underflow stream,
in which an effective amount of ultrasonic energy is applied to:
a) the bed of solids at the compression zone;
b) the sedimented solids in the underflow stream; or
c) a recycle stream containing sedimented solids taken from either the underflow stream or the compression zone which are then recycled back to the vessel in which a chemical agent is applied to the aqueous suspension of solid particles,
wherein the chemical agent is selected from the group consisting of at least one of an oxidising agent, free radical agent and reducing agent.

2 . The process according to claim 1 , in which the ultrasonic energy applied to the bed of solids or the underflow will be in the range of 0.1 to 1000 Watts seconds/millilitres specific energy.

3 . The process according to claim 1 , in which the ultrasonic energy is applied at a frequency in the range of 1 KHz to 10 MHz.

4 . The process according to claim 1 in which the ultrasonic energy is applied only to the bed of solids, to the underflow or a stream taken from the bed of solids all the underflow and recycled back to the vessel.

5 . The process according to claim 1 , wherein the ultrasonic energy is applied by fixing ultrasonic transducers around the inside or outside of a sidewall of the vessel or to rakes at the height of the bed of solids, the transducers being connected to a control unit which can adjust the power output of the transducer to a desired power density.

6 . The process according to claim 1 in which the ultrasonic energy is applied to the bed of solids from a rake.

7 . (canceled)

8 . The process according to claim 1 in which the chemical agent is applied to the bed of solids, the underflow or a stream taken from the bed of solids or the underflow and recycled back to the vessel.

9 . The process according to claim 1 in which an agent system is applied to the aqueous suspension of solid particles, wherein the agent system comprises i) at least one oxidising agent as the at least one active agent; and ii) at least one control agent,
wherein the at least one control agent consists of iia) at least one activator component and/or iib) at least one suppressor component, in which the at least one activator component increases the activity of the oxidising agent and the suppressor component decreases the concentration or the activity of the activator component.

10 . The process according to claim 1 in which the vessel is a gravimetric thickener.

11 . The process according to claim 1 in which the aqueous suspension of solid particles comprises mineral particles.

12 . The process according to claim 1 in which the aqueous suspension of particles comprises red mud or tailings from metal extraction, acid leaching, coal, oil sands, mineral sands or other mining or mineral processing operations.

13 . The process according to claim 1 in which the organic polymeric flocculant is a non-ionic or anionic polymer that is either a synthetic polymer of intrinsic viscosity of at least 4 dl/g or a natural polymer.

14 . The process according to claim 1 in which the organic polymeric flocculant is selected from the group consisting of at least one homopolymer of acrylic acid or salts thereof, homopolymer of acrylamide and copolymer of acrylamide and acrylic acid or salts thereof.

15 . An apparatus suitable for concentrating an aqueous suspension of solid particles comprising:
a vessel, a means for introducing the aqueous suspension of solid particles into the vessel, a means for introducing at least one organic polymeric flocculant to the aqueous suspension of solid particles, sufficient to form flocculated solids, a means for allowing the flocculated solids to form compression zone comprising a bed of sedimented solids in the suspension at the lower end of the vessel, a means for flowing the sedimented solids from the vessel as an underflow stream, in which the apparatus comprises a means for applying ultrasonic energy to: a) the bed of solids at the compression zone; b) the sedimented solids in the underflow stream; or a recycle stream containing sedimented solids taken from either the underflow stream or the compression zone which are then recycled back to the vessel and in which the apparatus comprises a means for applying a chemical agent to the aqueous suspension of solid particles, wherein the chemical agent is selected from the group consisting of at least one oxidising agent, flee radical agent and reducing agent.

Assignees

• Basf Se

Inventors

• Berger Alexsandro
• Adkins Stephen

Classifications

• C02F1/72

  by oxidation {(C02F1/4672 takes precedence)} · CPC title

• B01D21/283

  Settling tanks provided with vibrators · CPC title

• B01D21/01

  using flocculating agents (for purifying water C02F1/52; for liquid radioactive waste G21F9/10) · CPC title

• C02F1/70

  by reduction {(C02F1/4676 takes precedence)} · CPC title

• B01D21/2488 Primary

  bringing about a partial recirculation of the liquid, e.g. for introducing chemical aids · CPC title