 DEAS 907: 2023  
ICS 65.080  
 
© EAC 2023                                                                                                                          Second  Edition 2023   
 DRAFT EAST AFRICAN STANDARD  
Fertilizers — Potassium sulphate (sulphate of potash)  — Specification  
EAST AFRICAN COMMUNITY  DEAS 907:2023  
ii © EAC  2023  – All rights reserved  
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© EAC 2023  – All rights reserved  iii 
 Foreword  
Development of the  East African Standards has been necessitated by the need for harmonizing requirements 
governing quality of products and services in the East African Community. It is envisaged that through 
harmonized standardization, trade barriers that are encountered wh en goods and services are exchanged 
within the Community will be removed.  
The Community has established an East African Standards Committee  (EASC)  mandated to develop and 
issue East African Standards  (EAS) . The Committee is composed of representatives of the National 
Standards Bodies in Partner States, together with the representatives from the public and private sector 
organizations  in the community .  
East African Standards are developed through  Technical Committees that are representative of key 
stakehol ders including government, academia, consumer groups, private sector and other interested parties. 
Draft East African Standards are circulated to stakeholders through the National Standards Bodies in the 
Partner States. The comments received are discussed and incorporated before finalization of standards, in 
accordance with the Principles and procedures for develop ment of East African Standards . 
East African Standards are subject to review, to keep pace with technological advances. Users of the East 
African  Standards are therefore expected to ensure that they always have the latest versions of the standards 
they are implementing .  
The committee responsible  for this document is Technical Committee EASC /TC 020, Agriculture and 
agrochemicals . 
 
 DRAFT EAST AFRICAN STANDARD  DEAS 907: 2023  
 
© EAC 2023  – All rights reserved  1 
 Fertilizers — Potassium Sulphate ( Sulphate of Potash)  — Specification  
1 Scope   
This Draft East African  Standard specifies  requirements , sampling and test methods for potassium sulphate 
(sulphate of potash) fertilizer.  
2 Normative references   
The following documents are r eferred to in the text in such a way that some or all of their content constitutes 
requirements of this document.  For dated references, only the edition cited applies. For undated references, 
the latest edition of the referenced document (including any ame ndments) applies.  
AOAC 928.02,  Chlorine (Water -soluble) in fertilizers  
AOAC 965.08, Water (free) in fertilizers — Vacuum -desiccatio n  
AOAC 974.01 , Sodium in fertilizers. Flame photometric  
AOAC 2006.03, Arsenic, Cadmium, Cobalt, Chromium, Lead, Molybdenum, N ickel and Selenium in fertilizers  
ISO 8157 , Fertilizer s, soil conditioners  and beneficial substances  — Vocabulary  
ISO 8397 , Solid fertilizers and soil conditioners — Test sieving  
ISO 10084 , Solid fertilizers – Determination of mineral – acid- soluble sulph ate content - Gravimetric method  
ISO 17318 , Fertilizers and soil conditioners — Determination of arsenic, cadmium, chromium, lead and 
mercury contents  
ISO 17319,  Fertilizers and soil conditioners ― Determination of water -soluble potassium content ― 
Potassiu m tetraphenylborate gravimetric method  
ISO 14820 -1, Fertilizers and liming materials - Sampling and sample preparation - Part 1: Sampling  
 ISO 148 20-2, Fertilizers and liming materials - Sampling and sample preparation - Part 2: Sample preparation  
ISO 7409 , Fertilizers  -Marking - Presentation and declarations  
 
3 Terms and definitions   
For the purposes of this document, the terms and definitions given in ISO 8157  apply.  
ISO and IEC maintain terminological databases for use in standardization at the following  addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp   
2 © EAC  2023  – All rights reserved  
  
4 Requirements  
4.1 General requirements  
4.1.1  The material shall be crystalline , prills, granular or powder , uniform  in colour  and free from any 
foreign matter.  
4.1.2  The particle size shall be such that at least 90 % by weight of the material shall be of particles in the 
size range of 1 mm to 4 mm for prills and 2 mm to 4 mm for granules or not less than 65 % particles in the 
size range o f 0.25 mm to 1.7 mm for powdered crystals. The fertilizer material shall be tested in accordance 
with ISO 8397 .  
4.2 Specific requirements  
Potassium sulphate (sulphate of potash)  fertilizer shall comply with the requirements given  in Table 1  when 
tested in  accordance with the test methods prescribed therein . 
Table  1 — Specific r equirements for potassium sulphate (sulphate of potash)  fertilizer  
S/N Characteristic  Requirement , 
% by mass  Test method  
i.  Potash content (as K 2O), min.  50 ISO 17319  
ii.  Sulphur (as S) , min.  17.5 ISO 10084  
iii.  Total chloride (as Cl), max.  2.5 AOAC 928.02  
iv.  Sodium content (as NaCl), max.  2.0 AOAC 974.01  
v.  Moisture content, max.  1.5 AOAC 965.08  
 
5 Contaminants  
5.1 Heavy metal contaminants in potassium sulphate (sulphate of potash)  fertili zer shall conform to the 
limits given in Table 2 when tested in accordance with the test methods prescribed therein . 
Table 2 — Requirements for heavy metal contaminants  in potassium sulphate (sulphate of potash)  
fertilizer   
S/N Heavy metal  Maximum r equirem ent, 
mg/kg  Test method  
i.  Arsenic  (As) 20 
ISO 17318  ii.  Cadmium  (Cd) 30  
iii.  Mercury  (Hg) 0.1 
iv.  Lead  (Pb) 30 
v.  Chromium  (Cr) 500 
vi.  Selenium  (Se)  1.0 AOAC 2006.03  
  
© EAC 2023  – All rights reserved  3 
 7 Packaging  
The fertilizer shall be packaged in materials that are clean and non -defective t hat protect the product from 
physical, chemical and moisture contamination and withstand multiple stages of handling (transportation and 
storage ). 
8 Labelling  
Each package shall be legibly and indelibly labeled in accordance with ISO 7409 in English and/or  any other 
official language  of the destination country  with the following information:  
a) name of the fertili zer; “Potassium sulphate (sulphate of potash ) fertilizer ”  
b)  brand name  if any ; 
c) name and address of the manufacturer/packer ; 
d) net content by mass, in metric units ;  
e) nutrient content as percent  by mass ; 
f) country of origin ; 
g) handling  instructions, including the words “ Use no hooks” ; 
h) production date   
i) expiry date ; 
j) batch number ; and  
k) storage conditions . 
9 Sampling  
Sampling and sample preparation of phosphate roc k powder  fertilizers shall be carried out as prescribed in 
ISO 14820 -1 and ISO 148 20-2 respectively . 
 
 
 
 
. DEAS 907: 2023    
 
© EAC 2023  – All rights reserved  
  
  