Reach Zinc - Cement copper (EC 266-964-1)

Cement copper (EC 266-964-1)

Substance description/characteristics

Name and other identifiers of the substance:

The substance Cement copper is a UVCB (origin: inorganic)

Public name: High Grade Cement Copper

Substance identity:
EC number:	266-964-1
EC name:	Cement copper
CAS number (EC inventory):	67711-88-0
IUPAC name:	Insoluble copper-containing residue after precipitation of copper bearing solutions
Description:	During the zinc refining process, cement copper is obtained when adding - a reducing agent i.e. Zinc powder, Fe-powder, Al-powder, H2, ...- to the Copper loaded Zinc Sulphate solution and precipitation (cementation) of a Copper-rich precipitate. - a neutralizing agent (e.g. Zinc oxide, Na(OH), ...).to the Copper loaded Zinc Sulphate solution and precipitation (hydrolysis) of a Copper-rich precipitate. - Cu+ containing solution to a Cl- containing Zinc Sulphate solution, or a reducing agent if the Zinc Sulphate solution is Cu++ rich, and precipitation of a CuCl rich precipitate After settling step, the precipitate is optionally re-pulped in a second reaction tank with a slightly acidic sulphate solution i.o.t. dissolve the excess of unreacted zinc powder and potentially co-precipitated Cadmium. The Copper-rich precipitate can be washed and filtered out of the suspension using press-filters
Molecular formula:	n.a.
Molecular weight range:	n.a.
Physical state:	Solid at 20°C and 1013 hPa

Source, process and conclusion

Source	The copper loaded Zinc Sulphate solution (ZnSO4 solution, EC 273-723-4) obtained from the leaching -intermediate step undergoes redox reactions to purify it from copper content. In the redox reactions reducing agent (i.e. Zinc powder, Fe-powder, Al-powder, H2, ...) and neutralizing agent (e.g. Zinc oxide, Na(OH), ...) are used with the Cu+ and Cl- containing Zinc Sulphate solution. Ratios of redox agents are adapted depending on the elemental composition o f the copper loaded zinc sulphate solution (EC 273-723-4), to ensure efficient purification from copper, allowing extraction of Cu and Cu-compounds from the feed.
Process	Cementation is a precipitation process in which ions are reduced to zero valence at a solid metallic interface and is used to refine the zinc leach solutions from the copper. During the hydrometallurgical production of metal and/or metal-compounds, redox-potential variations (cementation) result in the selective precipitation of a'copper-precipitate’ that concentrate copper and copper-compounds. Cement copper is obtained when adding: - a reducing agent i.e. Zinc powder, Fe-powder, Al-powder, H2, ...- to the Copper loaded Zinc Sulphate solution and precipitation (cementation) of a Copper-rich precipitate. - a neutralizing agent (e.g. Zinc oxide, Na(OH), ...).to the Copper loaded Zinc Sulphate solution and precipitation (hydrolysis) of a Copper-rich precipitate. - Cu+ containing solution to a Cl- containing Zinc Sulphate solution, or a reducing agent if the Zinc Sulphate solution is Cu++ rich, and precipitation of a CuCl rich precipitate After settling step, the precipitate is optionally re-pulped in a second reaction tank with a slightly acidic sulphate solution in order to dissolve the excess of unreacted zinc powder and potentially co-precipitated cadmium. The cement copper is further sent to industrial copper installations for further extraction of copper.
Conclusion	Insoluble copper intermediate, obtained by purification of zinc sulphate solution via cementation (redox process) and further used to extract copper. Source material is always the zinc sulphate solution intermediate ( EC 273-723-4), purified from its copper content by means of reducing or neutralizing agents (depending on the solution elemental composition) to obtain a copper intermediate that will be further processed in the Cu industry (for Cu extraction).

Classification

The boundary composition of Cement copper is detailed here below.

Elemental composition - boundary:

Core	min (% w/w)	max (% w/w)	typical (% w/w)
Cu	10	80	49.2
Zn	5	20	49.2
Cd	0.1	20	0.67
CaSO4	0	13.9	7
Fe	0.1	10	0.21
Pb	0.1	10	0.33
Ni	0	7	0.06
Co	0	10	0.01
Si	0	3	0.14
As	0.1	12	3.15
Sb	0.01	5	0.03
Cl	0.1	10	0.34
MgO	0	3	1.46
Mn	0	2	1.04

Mineralogical composition - boundary:

Core	min (% w/w)	max (% w/w)	typical (% w/w)
CuO	11.68	60	38.45
Cu	0.01	1	0.05
Cu3As	3.14	20	11.1
Cu2S	0.1	2	0.52
(CuZn)5(CO3)2(OH)6	13.24	52.96	21.5
ZnSO4	0.62	2.47	1.84
CdSO4	0.19	37	1.24
Ca(Zn(OH)3)2	1.5	25	12.59
Fe(OH)3	0.2	19.13	0.44
PbCl2	0.13	13.33	0.44
MgSiO3	0	3	1.46
Mg(OH)2	0.1	6.4	3.21
MgCl2	0.01	0.6	0.3
MgO	0.1	1.24	0.62
Sb2O3	0.013	6.67	0.04
Co2O3	0.03	27.8	0.014
NiO	0.01	8.9	0.08
As2O3	0.0001	0.13	0.01
Mn	0	2	1.04

4. Classification

The classification is always based on the worst case. For the cement copper, this corresponds to:
Acute toxicity - oral	Acute tox oral 2
Acute toxicity - inhalation	Acute tox inhal. 2
Skin corrosion / irritation	Skin corr. 1B
Serious eye damage / eye irritation	Eye damage 1
Respiratory sensitisation	Resp. sens. 1
Skin sensitisation	Skin. sens. 1
Germ cell mutagenicity	Muta. 2
Carcinogenicity	Carc. 1A
Reproductive toxicity	Repr. 1A
Specific target organ toxicity - repeated (STOT-RE)	STOT RE 1
Hazardous to the aquatic environment (acute / short-term)	Aquatic Acute 1
Hazardous to the aquatic environment (long-term)	Aquatic Chronic 1