GB/T 2441.7-2010 English PDF (GBT2441.7-2010)

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GB/T 2441.7-2010: Determination of urea -- Part 7: Particle size -- Sieve method
GB/T 2441.7-2010
GB
ICS 65.080
G 20
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Determination of urea -
Part 7. Particle size - Sieve method
ISSUED ON. JUNE 30, 2010
IMPLEMENTED ON. JANUARY 1, 2011
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People’s Republic of China;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3 
1  Scope ... 4 
2  Normative References ... 4 
3  Principle ... 4 
4  Instruments ... 4 
5  Analysis steps ... 5 
6  Results presentation ... 5 
Foreword
GB/T 2441 “Determination of Urea” is divided into 7 parts as follows.
Part 1. Determination of urea - Part 1. Total nitrogen content
Part 2. Determination of urea - Part 2. Biuret content - Spectrophotometric method
Part 3. Determination of urea - Part 3. Water content - Karl Fischer method
Part 4. Determination of urea - Part 4. Iron content - 1,10-Phenanthroline
spectrophotometric method
Part 5. Determination of urea - Part 5. Alkalinity - Titrimetric method
Part 6. Determination of urea - Part 6. Water insoluble matter content - Weight method
Part 7. Determination of urea - Part 7. Particle size - Sieve method
This part is part 7 of GB/T 2441.
This part replaces GB/T 2441.7-2001 "Determination of urea - Determination of particle
size – Sieve method".
Compared with GB/T 2441.7-2001, the main changes of this part is. In analysis steps, add
manual screening.
This part was proposed by the China Petroleum and Chemical Industry Association.
This part shall be centralized by the National Standardization Technical Committee of
Fertilizer and Soil Conditioner (SAC/TC 105).
Drafting organizations of this part. National Fertilizer Quality Supervision and Inspection
Center (Shanghai).
Main drafters of this part. Zhang Qiuzhen, and Sun Dan.
The previous versions replaced by this part are as follows.
- GB/T 2448-1981, GB/T 2448-1991, and GB/T 2441.7-2001.
5 Analysis steps
5.1 According to the tested materials, and according to the particle size d (0.85 mm - 2.8
mm, 1.18 mm - 3.35 mm, 2.00 mm - 4.75 mm, 4.00 mm - 8.00 mm) to select a set of (2)
corresponding test sieves.
5.2 According to the size of hole-diameter, pile up the sieves in the sequence from
large-size to small-size (large-size at upper, small-size at lower). Mount on the chassis.
Weigh about 100 g of laboratory sample (accurate to 0.5 g). Place the sample onto the
sieves that have been piled up. Cover the sieves. Place on the oscillator. Clamp well.
Oscillate for 3 min; or manually sieve-screen it. Weigh the samples that have gone
through the large-hole sieve and have not gone through the small-hole sieve. The
particles stuck in sieve-hole are counted as not-go-through.
6 Results presentation
Particle size w, expressed in mass fraction (%), shall be calculated according to formula
(1).
Where.
m1 – The mass value of samples that have gone through the large-hole sieve and have
not gone through the small-hole sieve, in units of grams (g);
m – The mass value of the sample, in units of grams (g).
The calculation result is expressed to 1 decimal place.