Abstract SYMPHOS 2011

LAKE TEST METHODS
Moisture Analysis. Are done gravimetrically using a Precisa XM 10 SE Moisture Analyzer. A single layer of the
fertilizer sample is place in a shallow 100 mm diameter metal sample dish (supplied with analyzer). Moisture loss
is determined at 105°C and the end point is determined automatically as per the “ADAPTSTOP” settings on the
instrument. Analyses are performed in quadruplicate with the average reported.
Granule Breaking Strength A Mecmecin Compact Force Gauge (Digital), rated to 200 N (20 kg) is used to
determined the fertilizer granule strength. The average breaking strength values of 20 granules are used to
calculate the final breaking strength for the specific fertilizer sample received.
Post coating residual powder analysis The free powder analysis is based on the standard IFDC S-122 method. A
measured sample (250 g) is passed through the column five times to remove the maximum amount of powder. The
amount of powder is expressed as a ppm value for the specific fertilizer sample.
Coating Application Depending on sample size the Biofix coatings are either applied using a modified cement
mixer or a 5 L rotating coating drum. Biofix sample are spayed onto the sample at room temperature (22 – 25°C),
unless otherwise stated, using a handheld DIY spray-gun fitted to a nitrogen cylinder regulated to between 100
and 200 kPa.
Attrition. With Lake’s attrition test, the wear of fertilizer granules is simulated. Samples of approximately 150 g
are sealed in a high strength plastic bag and placed in the handling simulator. The instrument rotates is run for 5
minutes at 30 rpm after which the latent powder value of the tested fertilizer is determined using Lake’s standard
powder analysis method.
I - Assuming e.g. 5% addition
II - IFS Proceeding 584 New Developments in Fertiliser Coatings EA Bijpost and JG Korver. 2006
136