The SPINDEN Reactor for MCP/DCP Production

The SPINDEN is used to agglomerate solid raw materials with a minimum amount of liquid phase resulting in a very low recycle ratio.

The special flexible casing permits the agglomeration of the thixotropic phosphate compounds that are common to both fertilizers and animal feed products.

The original concept of the SPINDEN was derived from the need to minigranulate a modified single (normal) superphosphate to produce a patented product "Multi-Phosphate Magneriano". Manah S.A. in Brazil owns this patent and has been using the SPINDEN to produce approximately 400,000 tpy of this material. The SPINDEN is available under license from KEMWorks for MCP/DCP animal feed ingredient production.


Features

Flexible Casing

A flexible casing is used to avoid the build up that occurs when agglomerating thixotropic compounds. An agglomerator with a rigid casing uses excessive power and at the same time is limited to relatively low tip speeds on the paddles or pins. In the SPINDEN, thixotropic compounds build up to a certain thickness (related to the type of rubber used to make the casing) before the movement of the casing causes the build-up to break off. The SPINDEN stays in operation with low power requirements.

Variable - High Speed

Since the D50 particle size is inversely proportional to the tip speed, traditional low speed rigid cased blungers (or pug mills) tend to produce a D50 of 2.0 to 4.0mm. The D50 for a SPINDEN can be varied from 0.8mm to 3.5mm by varying the shaft speed. This enables the product size to be "tuned" easily to compensate for changes in raw materials or product demand.

Pin-Paddles

The SPINDEN has hybrid pin-paddles with special angle of attack to maximize the effects of compression and coalescence that are directly responsible for the agglomeration of the raw materials.

Result - Low Recycle Ratio

The special pin-paddles coupled with the liquid distribution system and the production of the correct sized D50 help reduce the recycle ratio to a minimum.

With the classic pug mill system the recycle ratios for the production of minigranular Dicalcium Phosphate or Monocalcium Phosphates range from 5:1 up to 12:1. The main reason for this is that the D50 for the product is 1.00mm but from a blunger/pug mill the D50 is typically greater than 2.5mm. This means that a large amount of material has to be crushed and then recycled.

The recycle ratio for minigranular DCP when using the SPINDEN is 2 or 3:1 and for MCP it is about 3 to 4:1. This is because the D50 particle size leaving the SPINDEN is only about 1.2mm. The higher tip speed also results in a much more uniform size distribution. This means that the percentage of on-size product is also greater, and with the same screen efficiency the recycle ratio is also reduced.

Reference List

Client	Date	Product	Capacity Design/Actual	Features
Serrana Fosfatos S.A. Cajati S.P. Brazil	1997/8	Mini-granular Dicalcium Phosphate	35 tph	SPINDEN
Cargill Crop Nutrition  Riverview, Florida, USA	1996	Mini-granular Monocalcium & Dicalcium Phosphate	20 stph	KEMWorks Batch Defluorination
IAP S.A. Cubatao S.P. Brazil	1995	Mini-granular Dicalcium Phosphate	15 tph	SPINDEN
Manah S.A. Uberaba M.G. Brazil	1989	Multi Phosphate Magneriano	25 / 38 tph	SPINDEN
Manah S.A. Rio Grande R.S. Brazil	1987	Multi Phosphate Magneriano	20/ 25 tph	SPINDEN
Manah S.A. Cubatao S.P. Brazil	1986	Multi Phosphate Magneriano	20 / 35 tph	SPINDEN