GB/T 8571-2008Preparation of laboratory samples for compound fertilizers (English PDF)

Foreword

This standard is one of compound fertilizer series of standard test methods, which are listed below national standards.

--- GB/T 8571 "compound fertilizer laboratory sample preparation";

--- GB/T 8572 "After distillation of total nitrogen content for compound fertilizers - Titrimetric method";

--- GB/T 8573 "Determination of phosphorus content in compound fertilizer quinoline phosphomolybdate gravimetric method";

--- GB/T 8574 "Determination of potassium content for compound fertilizers - Potassium tetraphenylborate gravimetric method";

--- GB/T 8576 "free water for compound fertilizers - Determination vacuum oven method";

--- GB/T 8577 "free water for compound fertilizers - Determination Karl Fischer method." This standard replaces GB/T 8571-2002 "compound fertilizer laboratory sample preparation." This standard and GB/T 8571-2002 The main differences are. the standard format has been rewritten. The standard proposed by China Petroleum and Chemical Industry Association.

1 Scope

This standard specifies using a condensing points, grinding and other operations, the acquired original granular fertilizer into the sample preparation laboratory samples for analysis using.

This standard applies only to chemical or compound fertilizers obtained by the nitrogen, phosphate and potash-based fertilizer made by secondary processing complex Mixed fertilizer.

Principle 2 Riffle or by quartering the sample into two equal parts, to the part of the sample and the sample by mixing section to discard the sample down to Requirement, then milled through the sieve to a predetermined, to obtain a uniform, representative for the analysis of laboratory samples (samples known) used.

3 Instrument

3.1 grid slot riffle. Figure 1, or other riffle have the same effect.

3.2 grinder or mortar.

3.3 test sieve. aperture of 0.5mm, 1.00mm, with chassis and screen lid;

3.4 enamel pan or shovel. its width and grid slots should riffle (3.1) is equal to the width of the hopper.

4 Sample points reduction

5 Sample mill

The bottle will be 4.3 times reduction of sub-samples were taken after about 100g, milling or grinding mortar to all through 0.50mm aperture Screen (for wet manure by 1.00mm aperture sieve), mixed, placed in a clean, dry bottle, for composition analysis. Grinding operation to Quickly, in order to avoid loss of water during grinding or moisture, and to prevent overheating of the sample. The remaining laboratory samples for particle size measurement.