GB 34458-2017Feed additive - Dipotassium hydrogen phosphate (English PDF)

3.1 Appearance and properties

A white powder or crystalline granular material, readily soluble in water.

3.2 Technical indicators

The technical indicators shall comply with the requirements of Table 1.

Table 1 lists nine controlled items with their limits: the dipotassium hydrogen phosphate content expressed as the salt, as phosphorus and as potassium, all on a dry basis, and the maximum admissible contents of fluorine, lead, arsenic and chromium, together with the loss on drying and the water-insoluble matter.

4.1 Sensory examination

The appearance and the odour of the product are examined visually and by smell.

4.2 Identification test

The identification is carried out in two parts: the phosphate ion is identified by the yellow precipitate formed with silver nitrate solution, which dissolves in excess ammonia solution or in nitric acid solution; the potassium ion is identified by the flame test, the flame being observed through cobalt glass.

4.3 Determination of dipotassium hydrogen phosphate

The principle is gravimetric: in an acid medium quinoline molybdate is used as the precipitant to throw the whole of the phosphate in the test solution as quinoline phosphomolybdate, and the precipitate is filtered, dried and weighed, from which the dipotassium hydrogen phosphate content of the sample is calculated.

4.4 Determination of the potassium content

The potassium is precipitated as potassium tetraphenylborate, and the precipitate collected in a sintered glass crucible is dried and weighed. The mean of two parallel determinations is taken as the result.

4.5 Determination of the fluorine content

The sample is dissolved in hydrochloric acid solution and made up to volume, and the determination then follows GB/T 13083-2002.

4.6 Determination of the lead content

Determined in accordance with GB/T 13080.

4.7 Determination of the arsenic content

Determined in accordance with Clause 5 of GB/T 13079-2006.

4.8 Determination of the chromium content

Determined in accordance with GB/T 13088.

4.9 Determination of the loss on drying

Determined by the method of A.11 in Annex A of GB 25561-2010.

4.10 Determination of the water-insoluble matter

Determined by the method specified in A.5 of Annex A of GB 25561-2010.

5.1 Batching

Products of the same raw material and the same production process, produced continuously or in the same production shift, form one batch, subject to a ceiling on the mass of a single batch.

5.2 Sampling

Sampling is carried out in accordance with GB/T 14699.1.

5.3 Factory inspection

Of the items listed in Table 1, potassium, phosphorus, loss on drying and fluorine are the factory inspection items.

5.4 Type inspection

The type inspection items are all the requirements of Clause 3. In normal production a type inspection is carried out at least once every half year, and in addition in any of the following cases: a) when the product is being type-approved; b) when there is a major change in the production process or in the source of the raw materials that could affect product quality; c) when production is resumed after having been suspended for three months or more; d) when there is a substantial difference between the factory inspection result and the result of the previous type inspection.

5.5 Decision rules

If any one indicator of the inspection result fails to meet the requirements of this standard, a fresh sample shall be taken from double the number of packages and the determination repeated. If even one indicator still fails to meet the requirements of this standard, the whole batch is judged non-conforming.

6.1 Label

The label shall comply with GB 10648.

6.2 Packaging

The packaging material shall be non-toxic, harmless and moisture-proof.

6.3 Transport

During transport the packaging shall be protected from damage, from sunlight and from rain, and the product shall not be carried together with toxic or harmful substances.

6.4 Storage

During storage the product shall be protected from sunlight and rain, and shall not be stored together with toxic or harmful substances.