This standard was first issued in 1981. This standard replaces GB/T 13256-1991 from the date of implementation. This standard is a revision of GB/T 13256-1991 "Determination of sulfate content in industrial urea - Visual turbidimetric method". This standard specifies the determination of sulfate content in urea by visual turbidimetric method. This standard is applicable to the determination of sulfate content in industrial urea synthesized from ammonia and carbon dioxide. The main technical differences between this standard and GB/T 13256-1991 are: the basic standard HG/T 2843-1997 for the chemical industry is cited, and the GB/T 601 series standards are no longer cited. This standard is Part 8 of GB/T 2441 "Determination Method of Urea". GB/T 2441.8-2001 Determination method of urea - Determination of sulfate content - Visual turbidimetric method GB/T2441.8-2001 Standard download decompression password: www.bzxz.net

GB/T 2441. 8--2001www.bzxz.net
This standard is a revision of GB/T13256-1991 "Determination of Sulfate Content in Industrial Urea - Visual Turbidimetry". The main technical differences between this standard and GB/T13256-1991 are: the basic standard HG/T2843-1997 for the chemical industry is cited, and the GB/T601 series standards are no longer cited. This standard is Part 8 of GB/T2441 "Determination Method for Urea". GB/T2441 also includes the following parts:
Part 1 GB/T2441.1-—2001
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
Part 9
GB/T 2441.2--2001
GB/T 2441. 3--2001
GB/T 2441.4—-2001
GB/T 2441.5—2001
GB/T 2441.6—2001
GB/T 2441. 7--2001
GB/T 2441.9--2001
Urea determination method
Urea determination method
Urea determination method
Urea determination method
Urea determination method
Urea determination method
Urea determination method
This standard shall replace GB/T13256-1991 from the date of implementation. This standard is proposed by the State Administration of Petroleum and Chemical Industry. Determination of total nitrogen content
Determination of diammonium content Spectrophotometric method
Determination of water content Karl Fischer method
Determination of iron content o-phenanthroline spectrophotometric method Determination of alkalinity Volumetric method
Determination of water insoluble matter content
Gravimetric method
Determination of particle size Sieving method
Determination of methylene diammonium content
Spectrophotometric method
This standard is under the jurisdiction of the National Technical Committee for Standardization of Fertilizers and Soil Conditioners and is responsible for interpretation. The drafting units of this standard are: National Fertilizer Quality Supervision and Inspection Center (Shanghai), PetroChina Urumqi Petrochemical Company Fertilizer Guangdong, Sinopec Jiujiang Branch, Hainan Fudao Chemical Co., Ltd. The main drafters of this standard are: Zhang Qiuzhen, Yang Jiqun, Sha Yanping, Li Xianjia. This standard was first issued in 1981.
1 Scope
National Standard of the People's Republic of China
Determination of urea
Determination of sulphate content-Visible turbidimetric method
Determination of urea
Determination of sulphate content-Visible turbidimetric method This standard specifies the determination of sulfate content in urea by visual turbidimetric method. GB/T 2441.8-2001
Generation GB/T13256—1991
This standard applies to the determination of sulfate content in industrial urea synthesized from ammonia and carbon dioxide. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. HG/T2843-1997 Commonly used standard titration solutions, standard solutions, reagent solutions and indicator solutions in chemical analysis of fertilizer products 3 Principle
In an acidic medium, add barium chloride solution and generate white suspended particles of barium sulfate with sulfate ions. The turbidity formed is compared with the standard turbidity.
4 Reagents and solutions
Unless otherwise specified, the reagents, solutions and water used in this test method shall comply with the requirements of HG/T2843-1997. 4.1 Barium chloride solution, 50g/L;
4.2 Hydrochloric acid solution, 1+3;
4.3 Sulfate (SO2-) standard solution, 0.1 mg/mL. 5 Instruments
General laboratory instruments and
5.150ml. Colorimetric tube.
6 Analysis steps
6.1 Preparation of standard turbidity solution
Into 8 50mL colorimetric tubes, add 0, 0.50mL, 1.00mL, 1.50mL, 2.00mL, 2.50mL, 3.00mL, 3.50mL of sulfate standard solution respectively, add 5mL of hydrochloric acid solution, add water to 40mL, and set aside. 6.2 Determination
Weigh about 10g of laboratory sample (accurate to 0.1g), dissolve the sample in 2530ml hot water, add 20mL hydrochloric acid solution, heat and boil for 1~2min. If the solution is turbid, filter it with tight filter paper and wash it with hot water for 3~4 times. Collect the filtrate and washing liquid in a 100ml volumetric flask, cool it, dilute it with water to the scale, and mix it. Pipette 25.0ml of test solution into a 50ml colorimetric tube, add water to 40ml, and at the same time as the standard turbidimetric tube in 6.1, add 5ml of barium chloride solution under constant shaking, dilute it with water to the scale, shake it well and let it stand for 20min, and compare it with the standard tube. Expression of analysis results
The sulfate content (X) in the sample is expressed as the mass fraction (%) of sulfate radical (SO-), calculated as follows: 4V×0.0001×100
V(0.1/1000)
(25/100)m
×100 =
Wherein: V is the volume of the sulfate standard solution in the standard turbidimetric solution with the same turbidity as the test part, mI; m is the mass of the sample, g.
The obtained result is expressed to four decimal places.
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