Zinc metal (EC 231-175-3)
Zinc Substances > Zinc Substances

Substance description/characteristics

1. Name and other identifiers of the substance:

The substance zinc is an element having the following characteristics and physical–chemical properties (see the IUCLID dataset for further details).

The following public name is used: zinc metal

1.1 Substance identity

EC number: 231-175-3
EC name: zinc
CAS number (EC inventory): 7440-66-6
CAS number: 7440-66-6
IUPAC name: zinc
Synonyms: zinc
Molecular formula: Zn
Molecular weight range: 65.408


Structural formula:   Zn

1.2 Composition of the substance

Overall information on composition:

Composition Related composition(s)

zinc (boundary composition of the substance)

 

Zinc powder (boundary composition of the substance)

 

Name: zinc

(boundary composition of the substance)

State/form: solid: bulk

Degree of purity: >97.5 - <99.995 % (w/w)

Description: zinc metal in different forms - this describes primary zinc (Z1, Z2, Z3, Z4 and Z5) and secondary zinc (ZSA, ZS1, and ZS2) For galvanising applications, cf. ISO 1461: zinc bath must contain less than 1.5% alloying elements (excl. Sn and Fe) and 2% (incl. Sn and Fe) Methods of manufacture of substance: Manufacture of zinc metal by RLE In the hydrometallurgical, or “RLE” (= Roasting, Leaching, Electrolysis) process, zinc bearing material (e.g. ore concentrate containing zinc sulphide) is roasted to ZnO, which is then dissolved in sulphuric acid to make zinc sulphate solution. This solution is purified in several steps and, subsequently subjected to electrolysis. Electro-winning - The Zinc sulphate solution circulates continuously between the electrolytic-cells in the cell-house and the atmospheric coolers outside the building - The temperature is kept around ~37°C and current is applied between the series of Pb-anodes and Al-cathodes - Zinc deposits at the cathode and O2 evolves at the anode - A foaming agent is added in order to have a blanket of foam at the solution surface in the cells, and occasionally a cover on the cells, i.o.t. prevent aerosols emissions - The zinc deposit is removed mechanically from the cathodes, washed and melted in automated furnaces - The anodes need also to be cleaned from occasional deposits (PbO2/MnO2/…) every 2-3 weeks and replaced by new anodes every ~18 months - The cells need to be cleaned up regularly from accumulating cellmud - The zinc cathodes are melted to produce the final ingots. The acid solution is recycled in the process. Manufacture of zinc metal by ISF Distillation process - zinc bearing materials (recycling stream, sintered calcines, zinc cakes, briquettes, ...) are fed to the furnace, molten and distilled. - the zinc vapor is further cooled in the condenser zone; the liquid zinc stream is optionally refined again in distillation columns. - Zn-slabs or ingots are then cast and packed Manufacture of zinc metal by electroplating Electrogalvanized (electroplated) coatings are created by applying zinc to steel sheet and strip by electrodeposition. The operation is continuous and coating thickness is controlled. Applied in a steel mill, sheet or strip is fed through entry equipment into a series of washes and rinses then into the zinc plating bath. The most common zinc electrolyte-anode arrangement uses lead-silver, or other insoluble anodes and electrolytes of zinc sulfates. The coating develops as positively charged zinc ions in the solution are electrically reduced to zinc metal and deposited on the positively charged cathode (sheet steel).

 

Table 1.2 Constituents (zinc)

Constituent Typical concentration Concentration range Remarks
zinc EC no.: 231-175-3 <=99.995 % (w/w) >98.5 - <=99.995 % (w/w)  

 

Table 1.3 Impurities (zinc) 

Constituent                          Typical concentration Concentration range Remarks
lead EC no.: 231-100-4 <=0.003 % (w/w) >0 - <1.5 % (w/w)  
cadmium EC no.: 231-152-8 <=0.003 % (w/w) >0 - <0.05 % (w/w)  
iron EC no.: 231-096-4 <=0.002 % (w/w)

>0 - <=0.12 % (w/w)

 
tin EC no.: 231-141-8 <=0.001 % (w/w) >0 - <=0.7 % (w/w)  
copper EC no.: 231-159-6 <=0.002 % (w/w) >0 - <=0.1 % (w/w)  
aluminium EC no.: 231-072-3 <=0.001 % (w/w) >0 - <=0.1 % (w/w)  

 

Name: Zinc powder

(boundary composition of the substance)

State/form: solid: particulate/powder

Description: Zn metal in the liquid phase can be quenched (depending on the morphology of the desired powder) in water or in inert gas streams - both processes occur in closed containers - The desired powder fraction, after careful drying and “classification” (sorting), is packed for further use. Shapes of gas atomization powders By varying the several parameters: design and configurations of the jets, pressure and volume of the atomizing fluid, thickness of the stream of metal etc. - it is possible to control the particle size distribution over a wide range. The particle shape is determined largely by the rate of solidification and varies from spherical, if a low heat capacity gas is employed, to highly irregular if water is used. In principle the technique is applicable to all metals that can be melted, and is commercially used for the production of iron, copper, including tool steels, alloy steels, brass, bronze and the low-melting-point metals, such as aluminium, tin, lead, zinc, cadmium.

 

Table 1.6 Constituents (Zinc powder)

Constituent Typical concentration Concentration range Remarks
zinc EC no.: 231-175-3 ca.96 % (w/w) >=94 - <100 % (w/w)  
zinc oxide EC no.: 215-222-5 ca.4 % (w/w) >=0.01 - <6 % (w/w)  

 

Table 1.7 Impurities (Zinc Powder)

Constituent Typical concentration Concentration range Remarks
iron EC no.: 231-096-4 ca.0.001 >=0 - <0.005 % (w/w)  
cadmium EC no.: 231-152-8 0.01 % (w/w) >=0 - 0.04 % (w/w)  
lead EC no.: 231-100-4 0.01 % (w/w) 0 - 0.1 % (w/w)  

 

Classification includes Zinc massive, zinc powder stabilised and zinc powder pyrophoric. This document mentions ONLY the endpoints for which the substance, in its differents forms, is classified.
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