Formation of copper(II), zinc(II), silver(I) and lead(II) ferrocyanides

Bellomo, Athos

doi:10.1016/0039-9140(70)80103-5

Cited by 49 publications

(17 citation statements)

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“…Leaching of cyanide from blast furnace sludge deposits may cause contamination of ground water. The solubility product of potassium zinc hexacyanoferrate(II) nonahydrate is comparatively low,

\begin{matrix} K_{sol} = 5.5 \times 10^{- 39} \end{matrix}

(Bellomo, 1970). Its solubility depends on pH as shown in Reaction [6].…”

Section: Resultsmentioning

confidence: 99%

Identification of a Crystalline Cyanide‐Containing Compound in Blast Furnace Sludge Deposits

Mansfeldt

Dohrmann

2001

J of Env Quality

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During blast furnace operation, a cyanide-containing muddy waste referred to as blast furnace sludge is generated in large amounts. In Germany it was and is still common practice to pump this sludge into surface deposits. Depending on species, cyanide has very different toxicity. To this day there is no information about the type of cyanide occurring in blast furnace sludge deposits. In order to identify the type of cyanide we investigated by means of wet chemical and powder X-ray diffraction analyses 37 samples of three blast furnace deposits. Wet chemical results indicate that both the extremely toxic free cyanide (HCN and CN ) and toxic weak metal-cyanide complexes, for example [Zn(CN)4]2-, are not present in the sludge. By powder X-ray diffraction we identified the crystalline cyanide-containing compound potassium zinc hexacyanoferrate(II) nonahydrate, K2Zn3[Fe(CN)6]2 x 9H2O, as the cyanide-bearing compound. Our study is the first that identifies potassium zinc hexacyanoferrate(II) nonahydrate in the environment. As the iron-cyanide complex [Fe(CN)6] is not acutely toxic, any direct hazard comes from cyanide occurring in the investigated wastes. Under the predominant pH milieu of the sludge (pH about 8) the solubility of potassium zinc hexacyanoferrate(II) nonahydrate is low, thus minimizing the mobility of cyanide.

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“…Leaching of cyanide from blast furnace sludge deposits may cause contamination of ground water. The solubility product of potassium zinc hexacyanoferrate(II) nonahydrate is comparatively low,

\begin{matrix} K_{sol} = 5.5 \times 10^{- 39} \end{matrix}

(Bellomo, 1970). Its solubility depends on pH as shown in Reaction [6].…”

Section: Resultsmentioning

confidence: 99%

Identification of a Crystalline Cyanide‐Containing Compound in Blast Furnace Sludge Deposits

Mansfeldt

Dohrmann

2001

J of Env Quality

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“…This was prepared by adding dropwise, under continuous stirring, the stoichiometric amount of a 0.1 M aqueous solution of CuSO4 to 100 ml of an aqueous solution of K4Fe(CN)6(0.2 M) + K2SO4(0.5 M) [5]. This was prepared by adding dropwise, under continuous stirring, the stoichiometric amount of a 0.1 M aqueous solution of CuSO4 to 100 ml of an aqueous solution of K4Fe(CN)6(0.2 M) + K2SO4(0.5 M) [5].…”

Section: Methodsmentioning

confidence: 99%

“…This was prepared, washed and dried in the same way as K2Cu3[Fe(CN)6]2.xH20 , but by using ZnSO4 as precipitating reactant [5]. This was prepared, washed and dried in the same way as K2Cu3[Fe(CN)6]2.xH20 , but by using ZnSO4 as precipitating reactant [5].…”

Section: Methodsmentioning

confidence: 99%

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Thermal analysis of some cyano compounds

Marco

1989

Journal of Thermal Analysis

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The thermal behaviour of the cyano compounds NaCN, K,,Fe(CN)6.3H20, KaFe(CN)6 , K3Co(CN)6 and K2Hg(CN)4 has been investigated by using conventional thermal analysis techniques and infrared spectroscopy. The results indicate the absence of "decomplexing'" reactions for all the complexes, and "internal" redox reactions for the compounds KaFe(CN)6, K3Co(CN) 6 and K2Hg(CN)4. In all the investigated cases, the formation of cyanate and carbonate is demonstrated.In aqueous solution the cyanide ion binds to transition metal ions to form complexes of high thermodynamic stability [1][2][3]. Some of them are inert too and they readily give rise to heteropolynuclear complexes with variable stoichiometry, depending on the experimental conditions of formation [4--6]. Compounds such as Ag4Fe(CN) 6, KAg3Fe(CN)6 and Hg2Fe(CN)6 (white) alter swiftly in air, while others, such as K2Zna[Fe(CN)6]2 or KLaFe(CN)6 (white), are stable for a long time. Very different behaviour is evident as regards "internal" and/or "external" reactions, depending on the nature both of the central ion of the cyano complex (inside the anion moiety of the compound) and of the counter cations [7]. On the whole, the presence of highly polarizing cations favours the oxidative decomposition of cyanide compounds [9].Seifer [10][11][12][13][14][15] has investigated the thermal behaviour of hexacyanoferrates(II) in an inert atmosphere by using compounds where the cation moiety was constitued by "free" or at most hydrated ions. The results showed a very complicated set of endo-and excthermic effects, but the interpretation given by Seifer allows one to outline a scheme of behaviour.* Supported by the Italian MPI. Presented at "Journ6es

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“…Here, we designated this AC treated with a silver solution as AC-Ag-R-FC. Two reactions may occur on the AC as following equation (Bellomo, 1970) onto AC-Ag-R-FC from AuðS 2 O 3 Þ 3À 2 solution were carried out by the following procedure. First, 1 g of AC-Ag-R-FC or other adsorbents were added to a conical flask that had already been filled with 100 ml of AuðS 2 O 3 Þ 3À 2 solution at a given initial gold concentration.…”

Section: Methodsmentioning

confidence: 99%

Adsorption of gold from thiosulfate solutions with chemically modified activated carbon

et al. 2017

Adsorption Science & Technology

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Adsorption of the gold-thiosulfate complex ion (AuðS 2 O 3 Þ 3À 2 ) on silver ferrocyanide (AgFC)-impregnated activated carbon in aqueous solution has been studied in order to find an effectual adsorbent for the thiosulfate extracting gold from ores. This study was performed using AgFCimpregnated activated carbon (AC-Ag-R-FC: AC: activated carbon, Ag: silver nitrate, R: heating, FC: potassium ferrocyanide) and an artificial aqueous solution of AuðS 2 O 3 Þ 3À 2 . Gold-thiosulfate complex adsorption kinetics and isotherm studies were carried out at pH ¼ 9.0 on modified materials. It has been also found that the adsorption fits the intraparticle diffusion and Freundlich isotherm well. In order to understand the adsorption mechanism, raw and modified materials were characterized by N 2 adsorption-desorption measurements at 77 K, scanning electron microscopy and X-ray photoelectron spectroscopy. The maximum adsorption capability of AuðS 2 O 3 Þ 3À 2 on AC-Ag-R-FC is 3.55 kgt À1. Clearly, the extraordinary adsorption capacity of AC for AuðS 2 O 3 Þ 3À 2 offers a new approach to address challenging gold-thiosulfate complex separation and could promote the future development of thiosulfate leaching gold process.

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Formation of copper(II), zinc(II), silver(I) and lead(II) ferrocyanides

Cited by 49 publications

References 1 publication

Identification of a Crystalline Cyanide‐Containing Compound in Blast Furnace Sludge Deposits

Identification of a Crystalline Cyanide‐Containing Compound in Blast Furnace Sludge Deposits

Thermal analysis of some cyano compounds

Adsorption of gold from thiosulfate solutions with chemically modified activated carbon

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