Technology

Colloidal Mixing Technology

  • 2.0 image001-2The “Rolls Royce of Mixers” – the high shear colloidal mixer, as used by Team Mixing Technologies, is the leading colloidal mixer in the industry, recommended by most grouting experts world-wide.
  • High-shear colloidal mixers are internationally recognized as the most efficient method of mixing cement-based grouts and other materials. Colloidal mixing results in very stable mixes which resist bleed and water contamination.
  • Rapid mixing of grouts containing sand, up to a sand/cement ratio of 4:1 and neat cement grouts, with water/cement ratios as low as 0.36:1 without additives. Ratios may be even lower with the addition of plasticizers or super-plasticizers.
  • Team colloidal mixers are very efficient at mixing bentonite and other clay products. The mixing process accelerates hydration and produces a more stable, homogenous product.

Advantages

Advantages of Team Colloidal Mixers

colloidal_2

  • Cost savings: The combined effect of highly efficient mixing action and the ability to mix low water/cement ratios allows for reductions in the cement content for a given strength. UCS testing of grout samples has indicated that a 10 MPa (1,450 psi) strength improvement can be achieved for a given density of grout as compared to simple paddle mixing.
  • Optimum mixing: Slurry is repeatedly re-circulated through the zone of high shear within the colloidal mill. This breaks down the clusters of dry particles (agglomerates) and ensures maximum dispersion of fluids and solids.
  • Speed: The vortex action within the mixing chamber rapidly assimilates solids into the high shear mill, resulting in very rapid batch times.  Also, as mixing occurs during the entire weigh cycle, actual mix cycle times are minimized.
  • Pressure discharge: The pumping action of the mixer enables rapid transfer of the mixed slurry directly to the agitation tank or final destination.
  • Compact footprint: The mixer also serves as a scale and pump, eliminating other equipment.
  • Automated self-cleaning option: Team’s unique design ensures the mixer and lines are cleaned after every discharge cycle and the subsequent wash water is recycled. No additional waste water is generated during normal production cycles.
  • Reliability: The combination of robust design, very few moving parts, auto-lubrication, and readily availability of spare parts ensures long life and reliability for the equipment.

Description

Description of Colloidal Mixing

  • 2.0 image005-2Colloidal Mill: The key element of the colloidal mixer is the colloidal mill which houses a high speed rotor (discar) operating at 2100 rpm within a close-fitting chamber housing. The clearance between the discar and the walls is approximately 3 mm (1/8”). Here, a high turbulence and shearing action is created capable of breaking down clusters of dry cement particles (agglomerates).
  • The colloidal mill also acts as a centrifugal pump and will discharge slurry into an agitation tank or directly onto rockfill aggregate in a haul truck or LHD. The colloidal mill is capable of generating a maximum discharge pressure of 200 kPa (30 psi) with a flow rate of up to 750 l/min (200 gpm) per mill. It is possible to increase the mills efficiency as a pump (thus giving it a higher pressure capacity) but this reduces its efficiency as a mixer. This lower pump efficiency translates into a higher energy input.  Depending on the required batch size, one to four colloidal mills may be incorporated into the mixer, each requiring a 22 kW (30 hp) electric motor.
  • Mixing Tank: The mixing tank, besides containing all ingredients, acts as a centrifugal separator. The centrifugal action of the circulating material spins the unmixed, thicker slurry towards the outside of the tank while the lighter portions of the mix move inwards, towards the throat of the tank and into the colloidal mill. Once through the mill, this lighter material is discharged tangentially into the vortex, blending with the unmixed material.
  • Multiple passes through the mill produces a progressively thicker mix until the entire mixture becomes homogenous. At this point the surface of the vortex has a smooth, uniform appearance and the mixer can no longer separate differing densities. Similarly, the vortex action inside the mixer rapidly assimilates admixtures, when used, into the slurry. Depending on mixer size, the entire mix cycle, once all materials are added, can take as little as 15 seconds.
  • Control Valves: The output from the colloidal mill is sent into one of two paths. Slurry is either directed tangentially back into the mixing chamber (mix cycle), creating the vortex action, or it is directed to the agitation tank or truck (discharge cycle). Pneumatic or manual pinch valves are used to divert slurry flow.
  • Self Cleaning: After a batch is discharged the mixer is refilled with water. This water is directed through a standpipe in the mixer tank to a spray nozzle which scours the inside of the mixer clean. This water remains in the mixer and is used in subsequent batches.
  • Control Valves: The output from the colloidal mill is sent into one of two paths. Slurry is either directed tangentially back into the mixing chamber (mix cycle), creating the vortex action, or it is directed to the agitation tank or truck (discharge cycle). Pneumatic or manual pinch valves are used to divert slurry flow.

Comparison

Comparison of Team Colloidal Mixers vs. Competitive Units

  • Comparison Pic replacementDon’t be fooled – all colloidal grout mixers are not alike. Team Mixing Technologies’ colloidal mixer utilizes a “true colloidal mill” that shears the cement particles. Other competitors use a centrifugal pump to simulate the shearing action which in reality, serves as a recirculation pump without the high-shear mixing action.
  • Each Team colloidal mill has two large 200 mm (8”) open throats coupled directly to the feed box, allowing full flow, enabling thicker mixes and allowing easier access for cleaning. Competitors utilizing a centrifugal pump have a small inlet connection, usually 75 to 100 mm, (3 to 4”), causing restrictions and potential cavitation problems with heavier mixes.
  • The discharge velocity of Team’s colloidal mills combined with the tangential inlets on the mixing vessel allows a high velocity vortex to be created resulting in superior mixing. Competitors often need the assistance of a secondary paddle-style mixer to produce a sufficient vortex for mixing.
  • Generally, Team’s colloidal mills require more power than the competitors – up to 22 kW (30 hp) per mill. Power utilized is directly proportional to the shear rate, hence the more power added the more shearing and the more rapid the mixing cycle.

Colloidal Mixer

(0.5 w:c ratio grout)

Paddle Mixer

(0.5 w:c ratio grout)

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Colloidal Mixer Prepared Grout

  • Homogenous
  • No cement agglomerates
  • Maximum hydration
  • Maximum strength

Paddle Mixer Prepared Grout

  • Non-homogenous
  • Many agglomerates
  • Incomplete hydration of cement particles within agglomerates
  • Lower strength

Colloidal Mixers

Colloidal Mixers

Colloidal mixer

The unique action of the colloidal mixer allows cement grouts to be mixed with water/cement ratios as low as 0.36:1 in the small hand fed mixers (150 and 300 litre sizes). Larger mixers can mix down to a 0.55:1 water:cement ratio (without the use of plasticizers or super-plasticizers). The mixers are particularly efficient at mixing bentonite and other clay products which accelerates the hydration process and yields a stable product. These mixers are not suitable for use with sand or larger aggregates.

The range of mixers can be configured for outputs from 2 to 40 m3/hr depending upon the mix design and material feed rates. Mixers can be placed on load cells for weigh batching of ingredients and integrated with PLC control systems for maximum productivity.

The batch is discharged via the colloidal mills at pressures up to 2 bar (30 psi) and rates up to 700 liters per minute (185 USgpm) per mill assembly. The colloidal mills now feature mechanical seals with a thermo-siphon seal cooling system.

Model

Batch Capacity

Typical Output1

Maximum Output2

Colloidal Mills

Power

Tornado 2000

2000 litres
530 USgal

25 m3/hr
110 USgpm

40 m3/hr
176 USgpm

4

22kW ea
30hp ea

Tornado 1600

1600 litres
420 USgal

20 m3/hr
90 USgpm

32 m3/hr
140 USgpm

3

22kW ea
30hp ea

Tornado 1200

1200 litres
315 USgal

15 m3/hr
65 USgpm

24 m3/hr
105 USgpm

2

22kW ea
30hp ea

Tornado 1000

1000 litres
265 USgal

12 m3/hr
55 USgpm

20 m3/hr
90 USgpm

2

22kW ea
30hp ea

Tornado 750

750 litres
200 USgal

9 m3/hr
40 USgpm

15 m3/hr
65 USgpm

2

22kW ea
30hp ea

Tornado 600

600 litres
160 USgal

7 m3/hr
30 USgpm

12 m3/hr
55 USgpm

2

22kW ea
30hp ea

Tornado 300

300 litres
80 USgal

3.5 m3/hr
15 USgpm

8 m3/hr
35 USgpm

1

22kW
30hp

Tornado 150

150 litres
40 USgal

2 m3/hr
10 USgpm

4.5 m3/hr
20 USgpm

1

15 kW
20hp

Note:
1. Output of mixer is dependent on ingredient feed rates including water supply and screw conveyor feed rates.
2. Output can be increased by adding a water pump and/or water weigh hopper above the mixer to reduce the batch cycle time. Output is also dependent on mix design and mixing time – contact a sales rep for guidance.

Colloidal/Paddle Mixers

Colloidal/Paddle MixersColloidal-Paddle mixer page

The colloidal/paddle range of grout mixers allows for a combination of both colloidal and paddle mixing to occur simultaneously or separately as required. Both mixers can be used for rapid mixing followed by use of the paddle only for agitation, thus saving power and unwanted heat generation. This allows batches of grout to be stored in the mixing tank until required.

Each colloidal mill can discharge the mixed material at pressures up to 30 psi (2 bar) and flows up to 700 litres per minute (185 gpm) per mill assembly. Tanks can also be fitted with outlets for connection to an appropriate transfer pump.

These mixers can handle thick grouts, with water:cement ratios as low as 0.45:1 without the use of superplasticisers. The mixers are very efficient at mixing cement, flyash and bentonites.

All mixers can be fitted with load cells which, in conjunction with PLC control, allow materials to be accurately batched in by weight. Two mixers can be used in tandem to produce a continuous supply of grout for such applications as lightweight cellular concrete or paste backfill.

Model Batch Capacity Nominal Output1 Colloidal Mills Power Paddles Power
TCP 12000 12,000 litres
3,170 USgal
36 m3/hr
160 USgpm
2 22 kW ea

30 hp ea

2 11 kW ea

15 hp ea

TCP 6000 6,000 litres
1,585 USgal
25 m3/hr
110 USgpm
2 22 kW ea

30 hp ea

1 11 kW

15 hp

TCP 4000 4,000 litres
1,055 USgal
22 m3/hr
95 USgpm
2 22 kW ea

30 hp ea

1 7.5 kW

10 hp

TCP 3000 3,000 litres
790 USgal
20 m3/hr
88 USgpm
2 22 kW ea

30 hp ea

1 5.6 kW

7.5 hp

TCP 2000 2,000 litres
530 USgal
15 m3/hr
66 USgpm
2 22 kW ea

30 hp ea

1 5.6 kW

7.5 hp

TCP 1500 1,500 litres
400 USgal
13 m3/hr
55 USgpm
1 22 kW

30 hp

1 3.7 kW

5 hp

TCP 1000 1,000 litres
265 USgal
10 m3/hr
44 USgpm
1 22 kW

30 hp

1 3.7 kW

5 hp

 

Notes:

  1. Output of mixer is dependent on ingredient feed rates including water flow and screw conveyor capacity as well as discharge rates, i.e. the use of colloidal mill(s) or a separate pump.