CLARIFICATION

REACTOR

THE CONCEPT

THE MAGRA HIGH-RATE THICKENERWAS DEVELOPED TO FULFILL THE ROLE OF ATHICKENER, REACTOR AND CLARIFIER

THE ADVANTAGES

MOST AFFORDABLE & VERSATILE HIGH-RATE THICKENER ON THE MARKET

BEST PERFORMANCE PER UNIT AREA AND SMALLEST FOOTPRINT OF ANY THICKENER

THICKENING COMBINED WITH CLARIFICATION

NO MOVING PARTS

MINIMAL MAINTENANCE AND LOWEST OPERATING COST OF ALL THICKENERS

QUICK RESPONSE AND LITTLE RESIDENCE TIME WITH ZERO LOCK-UP

PATENT PROTECTED

THICKENING

PASTE WITHOUT PAINPASTE WITHOUT PAIN MAGRA HIGH PERFORANCE MAGRA HIGH PERFORANCE THICKENER/REACTOR/CLARIFIERTHICKENER/REACTOR/CLARIFIER

THE DESIGN

1. CYLINDRICAL CONICAL TANK TO MAINTAIN HIGH-RATE THICKENING, PURE OVERFLOW CLARITY AND HIGH UNDERFLOW DENSITY 2. FEED PIPE CULMINATING IN “BULLHORNS” FOR REDUCED DISCHARGE VELOCITY

3. SLOPED HEIGHT ADJUSTABLE OVERFLOW LAUNDER PROVIDES SELF CLEANING

4. MIXING CHAMBER DESIGNED FOR NON DESRUCTIVE,THOROUGH SLURRY AND FLOCCULANT MIXING

5. CENTRAL DEWATERING PIPE & COLLECTOR CONE FOR INTERNAL DILUTION CYCLE

6. CONICAL BAFFLE TO SUSPEND FLOC BED AND PROVIDE AN INCLINED SURFACE FOR CONSOLIDATION

7 CONSOLIDATION CONE FOR EFFICIENT AND RAPID DEWATERING

8. DRAW OFF BOX DESIGNED FOR SUSTAINED UNDERFLOW WITHDRAWAL AND EASE OF MAINTENANCE

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HOW IT COMES TOGETHER – LOW DENSITY FEED

A suspension of solid particles in the carrier liquid at low density enters the mixing chamber and mixes with the flocculant. The mixing chamber extends down to the free settling zone. The downward velocity of the suspension suddenly decreases passing from the mixing chamber (small diameter) to the thickener tank (larger diameter).

The sudden decrease in the downward velocity allows the

large particles to settle out.

The small particles are carried upward and accelerate through the annular throat creating turbulence and collisions. The settling velocity of the fines particles increases as the particles grow larger. The upward flow velocity above the throat decreases until the top of the conical baffle is reached. When the settling velocity of the particles exceeds the upward velocity, the particles start to drop downwards and on its downward path collisions occur with upward moving particles. This causes agglomeration and the particles finally become large and heavy enough to drop back through the annular throat into the free settling zone. The fines particles form a floc bed which act as a filter and a clarified zone is formed above the floc bed. Clarified liquid overflows into the overflow launder.

The fines particles dropping down from the floc bed mixes with the feed exiting from the mixing chamber diverted by the collector cone. Coagulation of fines now takes place and fewer fines are carried upward through the throat. This increases the capacity of the Magra Thickener far beyond any other known unit. FLOW DIAGRAM FOR

LOW DENSITY FEED

The passage of solids particles exiting the mixing chamber and annular throat are intercepted by the inclined surfaces of the consolidation cone. Consolidation takes place and the particles slide or roll down the inclined surfaces. Liquid separating the solids is displaced and collects below the collector cone. Some liquid returns to the free settling zone resulting in continuous dilution of the free settling zone leading to faster settling of solids particles.

Liquid collected under the collector cone move up the dewatering pipe. Upward movement of the liquid in the dewatering pipe is caused by the difference in pressure at position 1 (liquid pressure) and position 2 (pressure due to liquid zone above floc bed plus floc bed density and feed density). The liquid in the dewatering pipe contains unspent flocculant which overflows into the mixing chamber and thereby acts to dilute and flocculate the feed. A continuous internal dilution cycle is created. Dilution further reduces flocculant consumption and settling rate is increased.

Density increases with consolidation and compaction due to the inter-granular contact pressure between the particles. The depth of the compaction zone can be used to control the underflow density. With an increase in height, the residence time increases and together with the additional pressure being exerted on the compaction zone allows for liquid to escape from the compaction zone thereby further increasing the density.

FLOW DIAGRAM FORLOW DENSITY FEED

HIGH DENSITY FEED – UP TO 55% SOLIDS!!

UNDERFLOW DENSITY – UP TO 73% SOLIDS

A suspension of solids particles in the carrier liquid at high density enters the mixing chamber and mixes with the flocculant. Because of the high density of the suspension there will be a level displacement in the mixing chamber. The top edge of the mixing chamber is modified to include V-notches similar in shape to the overflow launder V-notches. A portion of the overflow is diverted into the mixing chamber.

A second internal dilution cycle is now created with an increase in the upward flow velocity.

Much less dewatering is required at high feed density compared with low feed density to obtain the same underflow density. Increasing the up flow velocity to the previous low density condition will not affect the operation or the overflow clarity.

The thickener again operates like a low feed density unit. Flocculant consumption is at the same level as a low feed density unit.

The Magra High-Rate Thickener is self regulatory and both the internal dewatering cycles adjust automatically to accommodate feed conditions and provide for reliable operation.

FLOW DIAGRAM FORHIGH FEED DENSITY