A. Van Sandwijk's research while affiliated with HagaZiekenhuis van Den Haag and other places

Publications (27)

Article
In the present paper, a detailed study of the redox behavior of zirconium in the eutectic LiF-NaF system was carried out on an inert molybdenum electrode at 750 °C. Several transient electrochemical methods were used such as cyclic voltammetry, square wave voltammetry, chronopotentiometry, and open circuit voltammetry. The reduction of Zr (IV) was...
Article
Chemical grade zirconium contains about 1-3 wt% hafnium which is harmful for nuclear applications due to its high neutron-capture cross-section. In the present paper, Zr-Hf separation in Sn-Cu-Zr-Hf and Cu-Zr-Hf alloy systems using molten salt containing CuCl2 or CuF2 were thermodynamically evaluated and lab scale experiments on zirconium and hafni...
Article
In this paper, a detailed study of the electrochemical behavior of zirconium in the molten LiF-KF-ZrF4 system on an inert molybdenum electrode was carried out at 600 °C. Several electrochemical techniques were employed such as cyclic voltammetry, chronoamperometry and square wave voltammetry. The reduction of zirconium was found to be a multi-step...
Chapter
Pure zirconium metal is widely used as a construction material in nuclear reactors in the form of alloys such as zircaloy. For nuclear reactor materials, the metal zirconium should have a very low hafnium content of less than 0.01 wt%. So far, there are no efficient processes which dominate the industrial production of nuclear grade zirconium. In t...
Article
Full-text available
Zirconium is an ideal material for nuclear reactors due to its low absorption cross-section for thermal neutrons, whereas the typically contained hafnium with strong neutron-absorption is very harmful for zirconium. This paper provides an overview of the processes for separating hafnium from zirconium. The separation processes are roughly classifie...
Chapter
Zirconium is an ideal material for nuclear reactors due to its low absorption cross-section for thermal neutrons, whereas the typically contained hafnium with strong neutron-absorption is very harmful for zirconium. This paper provides an overview of the processes for separating hafnium from zirconium. The separation processes are roughly classifie...
Article
In order to investigate an alternative process for the production of primary aluminum via a sulfide intermediate, the electrochemical behavior of Al2S3 in molten salt has been studied on a laboratory scale. The effects of electrolyte composition, temperature, and cell design on the cell performance have been investigated. Temperature and cryolite a...
Article
Full-text available
In order to investigate an alternative process for the production of primary aluminum via a sulfide intermediate, the electrochemical behavior of Al2S3 in molten salt has been studied on a laboratory scale. The effects of electrolyte composition, temperature, and cell design on the cell performance have been investigated. Temperature and cryolite a...
Article
Full-text available
The electrowinning of zinc from zinc chloride with a molten chloride electrolyte was investigated. The electrolysis of zinc chloride shows ohmic limitations. The energy consumption is to a large extent determined by the anodic reaction, the evolution of chlorine. The chlorine gas plume was visualised in a see-through furnace and images were analyse...
Article
Electrodialysis of a sodium fluoride solution in a membrane cell reactor was studied as part of a process to bleed magnesium from process liquors of electrolytic zinc plants. Because, in industrial practice, the long-term stability of membranes is a must, performance of the membranes over a long time was studied. Scaling of one of the membranes occ...
Article
Full-text available
An experimental study was conducted to investigate the sulfidation kinetics of Al2O3 with CS2 gas. The experiments were carried out in a laboratory scale fluidized bed reactor at various temperatures. The objective was to investigate the feasibility of an alternative process for the production of primary aluminum using a sulfide intermediate. The r...
Article
The conversion of magnesium fluoride to magnesium hydroxide was studied as part of a process to bleed magnesium from zinc sulphate electrolyte. Most electrolytic zinc plants have to deal with accumulating magnesium in their process liquors as the natural magnesium bleed usually does not balance input from concentrates. The most common forced magnes...
Article
Low-grade sulphidic molybdenum ores were treated by using a combined processing route for a comprehensive recovery of molybdenum, copper, and other minor elements. As the first step, oxidation roasting was used to convert most of sulphides into metal oxides, during which 85–90% of sulphur was removed. Then both water and dilute sulphuric acid leach...
Article
Full-text available
Most electrolytic zinc plants have to deal with dissolved magnesium in their process liquors, as zinc sulphide concentrates contain small amounts of magnesium. Applied magnesium bleed methods are generally expensive and environmentally unfriendly. Recently, a new approach was suggested and discussed, which involves selective magnesium fluoride prec...
Article
Most electrolytic zinc plants have to deal with dissolved magnesium in their process liquors as zinc sulphide concentrates contain small amounts of magnesium. Applied magnesium bleed method are generally expensive and environmetally unfriendly. Recently, a new approach was suggested and discussed in which magnesium fluoride is selectively precipita...
Article
Although FeAsO4 can be precipitated at temperatures less then 473.15 with initial solution of As(V) and Fe(III), experimental testwork has showed that a stable crystalline ferric arsenate is not synthesized at temperatures below 483.15 from liquors containing Fe(III) and as(III), through in-situ oxidation. Precipitations have been conducted at temp...
Article
Most electrolytic zinc plants have to deal with dissolved magnesium in their process liquors, as zinc sulphide concentrates contain small amounts of magnesium. Applied magnesium bleed methods are generally expensive and environmentally unfriendly. In this paper, a new approach is suggested and discussed in which magnesium fluoride is selectively pr...
Article
Full-text available
An investigation into the cementation of iron chloride from a zinc-chloride melt at 400 °C has been carried out with zinc powder. The variables studied include preparation of the chloride melt and the amount of zinc added. The effect of lead, copper, and cadmium on cementation of iron has also been investigated. According to the results, it is poss...
Article
Cathodic regeneration of nitrous acid by electrochemical reduction of nitrates could yield a catholyte which is useful in the processing of manganiferous ores. The purpose of the present investigations was to study the cathodic reaction in an electrolytic cell with an acidic nitrate electrolyte. Electrochemical reduction of nitrate has been investi...
Article
Cathodic and anodic reactions in an acidic nitrate medium were studied in reference to the production of electrolytic manganese dioxide from pyrolusite (MnO2) ores by reductive leaching. Two USA ores were investigated. The reductant for the pyrolusite ore is produced cathodically in an electrolytic cell and can either be nitrous acid (HNO2) or nitr...
Article
A new approach to regenerating chloride in the form of HCl, to avoid the anodic production of chlorine during the electrowinning of metal chlorides, is investigated. The investigation utilizes a membrane cell to electrowin copper and nickel chloride. The chloride is recovered in the form of HCl in the catholyte with a single membrane cell and in th...
Article
A three-compartment electrowinning cell has been evaluated for the regeneration of HCl from metal chloride catholyte. By segregating the catholyte with an anion exchange membrane, and the anolyte with a cation exchange membrane from the middle electrolyte(ampholyte) compartment, HCl could be produced in the ampholyte electrochemically up to one mol...
Article
The invention is directed to a process for separating a mixture comprising hafnium and zirconium. The process of the present invention comprises a step in which a molten metal phase comprising zirconium and hafnium dissolved in a first metal M1 and a second metal M2 is contacted with a molten salt phase comprising at least one metal halide M3Z, whe...

Citations

... It is necessary to keep in mind that the chemicals to be used in such quantities cannot be kept ultrapure, and an industrial-grade purity level will have to be sufficient. In the context of this consideration, another group of authors has focused on, for example, purification or precipitation from, or pyroprocessing and even surface treatment of industrially-attractive compounds by fluoride melts [9,[17][18][19][20][21][22][23]. The literature describes various reprocessing problems connected with the natural humidity of potassium fluoride, [24,25] ranging from different moisture content [26,27] to problems with purifying using hydrofluorination [28,29]. ...
... Metallic zirconium may contain 1-4.5% of hafnium. For nuclear application, a hafnium separation should be made [4]. This process is expensive, so the hafnium separation process is not performed in the manufacture of the powders. ...
... This result was evidence of Nd deposition during the cathodic process, although its typical peak was indistinguishable from the CV curve. A similar phenomenon was reported by Hua et al. [18] in forming Mg-Nd alloy. ...
... The degassing of magma could reflect possible larger volatility of Hf-bearing species compared to Zr gaseous species. Recent results of experimental Zr and Hf separation from mixed melted salts reveal that HfCl 4 gas species are significantly more volatile compared to ZrCl 4 gas species (Xu et al., 2016). We propose that the observed fractionation in Tolbachik and Erta-Ale fumaroles can result from the strong affinity of Hf toward Cl-compared to Zr toward Cl − in agreement with different acid-base properties of these two metal ions (Shikina et al., 2015). ...
... Leaching of sulfide minerals with seawater is associated with leaching in chloride solution due to the presence of chloride in seawater. Chloride hydrometallurgy has been extensively studied in the literature (Winand, 1991), including leaching (Liddicoat and Dreisinger, 2007;Senanayake, 2009;Watling, 2013;Watling, 2014), solvent extraction (Szymanowski, 1996;Dreisinger, 2013a, 2013b), and reagent recovery (Vanweert and Peek, 1992;Liao et al., 1996). The study of chloride hydrometallurgy is beyond the scope of this review. ...
... Another contamination that is always present are Hf impurities in Zr precursors, since natural zirconium ores always contain around 1-3% of hafnium [24]. Hafnium and zirconium are chemically very similar, which makes the separation of this two materials even more expensive and complicated [25]. For example, in September 2020, the price for standard ZrO 2 (containing up to 2% hafnium) was around 150 € per kg, while for the purer one (< 100 ppm hafnium), the price reached 500 € per kg [26]. ...
... 17−19 Despite their chemical similarity, major uses of both Hf and Zr in industry exploit the very different neutron capture cross sections of their respective nuclei. Used as a nuclear fuel cladding material, Zr (e.g., Zircaloy) must contain less than 100 ppm of Hf/Zr, due to the high neutron absorption cross section of Hf. 20,21 This necessitates efficient separation to meet nuclear requirements, as well as to provide pure Hf for neutron capture applications, i.e., control rods for nuclear reactors. 22 The industrial process for Zr/Hf separation developed ∼70 years ago begins with mined Zr(Hf)SiO 4 (Hf ∼2 wt %). ...
... However, even if Zr-Hf fractionation through the magmatic degassing generates sub-chondritic Zr/Hf values, possible extensive interactions between Zr-depleted uprising volcanic fluids and pristine magmatic rocks of chondritic signature may progressively enhance the Zr/Hf ratio of fluids (Agashev et al., 2008;Yaxley et al., 1998). Furthermore, interactions between uprising magmatic fluids and host-rocks generate progressive fluid cooling with possible volatility changing that may destabilize Zr and Hf gaseous complex-ions (Larsen, 1970;Pastor, 1999;Pershina et al., 2002;Postma et al., 2015Postma et al., , 2017Shikina et al., 2015;Xiao et al., 2014;Xu et al., 2016). These two processes may explain variations of the linear of Zr/Hf temperature trend tentatively displayed in dished line (1) of Figure 3. ...
... The production of CS 2 is a proven technology and possibilities of electrowinning Al from Al 2 S 3 is addressed by Lans et al. (Lans, Bohte et al., 2003;Xiao, Soons et al., 2003;Xiao, Van Der Plas et al., 2004). By this process, the current efficiency of 60% was obtained compared to the average values of 90-95% in the modern Hall-Heroult process for aluminium production (Xiao, van der Plas et al., 2007). ...
... Dumasp's research showed that the use of Ar as an ion source to assist gas deposition increased the bulk density of MgF 2 films, but excessive particle energy led to a change in the stoichiometric ratio of Mg and F, resulting in F atom vacancies, which led to the absorption of ultraviolet and visible parts [12,13]. These studies further show that excessive Ar + ion energy can lead to more serious moisture absorption problems when MgF 2 thin films are evaporated by an electron gun [14]. ...