Rhenium(VII) Compounds as Inorganic Precursors for the Synthesis of Organic Reaction Catalysts.

Rhenium is an element that exhibits a broad range of oxidation states. Synthesis paths of selected rhenium compounds in its seventh oxidation state, which are common precursors for organic reaction catalysts, were presented in this paper. Production technologies for copper perrhenate, aluminum perrhenate as well as the ammonia complex of cobalt perrhenate, are thoroughly described. An ion exchange method, based on Al or Cu metal ion sorption and subsequent elution by aqueous perrhenic acid solutions, was used to obtain perrhenates. The produced solutions were neutralized to afford the targeted aluminum perrhenate and copper perrhenate products in high purity. The developed technologies allow one to manage the wastes from the production of these perrhenates as most streams were recycled. Hexaamminecobalt(III) perrhenate was produced by a newly developed method enabling us to produce a high purity compound in a reaction of spent hexaamminecobalt(III) chloride solution with a perrhenic acid. All prepared compounds are the basis for precursor preparation in organic catalysis.

Application of ion-exchange dynamic conditions in the recovery of precious metals from refining waste.

The objective of this study was to assess the potential for recovering precious metals from technological solutions using an ion-exchange dynamic method. Precious metals like platinum, palladium, rhodium, and gold are essential materials in various industries such as: automotive, electronics, pharmaceuticals, and jewellery. Due to their limited occurrence in primary sources, there is a growing trend in the market to extract these metals from secondary sources. The research involved conducting sorption and elution tests under different parameters to investigate their impact on the process in dynamic conditions. Additionally, an attempt was made to calculate the operational and total capacity of the resins, which has not been done previously for industrial solutions. The results showed that using Puromet MTS9200, Puromet MTS9850, and Lewatit MonoPlus MP600 resins, the sorption process could be effectively carried out in dynamic conditions with a contact time of 5 min between the technological solution and the resin bed. For optimal elution, the contact time between the eluent solution and the bed should range between 10 and 30 min. To improve rhodium sorption efficiency, it was found that neutralizing the technological solution to a pH of approximately 7 and using Lewatit MonoPlus MP600 resin could be beneficial.

Solvent Extraction as a Method of Recovery and Separation of Platinum Group Metals.

Platinum group metals (PGMs) are a group of six metals with high market value and key importance to many industrial sectors. Due to their low prevalence in the Earth's crust and high demand, these metals have been recognized as critical materials for many years. Along with economic development, the natural resources of the platinum group metals are gradually depleting, which is accompanied by the need to recover PGMs from secondary sources. The solutions resulting from the processing of such materials are characterized by high content of impurities and low content of precious metals. For this reason, in order to obtain pure metals, it is extremely important to choose an effective, selective method for the recovery and separation of the platinum group metals. This review focuses on the most important aspects of the characteristics of the PGMs, including their properties and occurrence, the processing of natural and secondary raw materials and the role of liquid-liquid extraction in the selective separation of metals from this group, not only on a laboratory scale but, above all, on an industrial scale. In addition, this study collects information on the most commonly used, commercially available extractants, based on current reports, taken from the scientific literature.

The Use of ZrO2 Waste for the Electrolytic Production of Composite Ni-P-ZrO2 Powder.

Ni-P-ZrO2 composite powder was obtained from a galvanic nickel bath with ZrO2 powder. Production was conducted under galvanostatic conditions. The Ni-P-ZrO2 composite powder was characterized by the presence of ZrO2 particles covered with electrolytical nanocrystalline Ni-P coating. The chemical composition (XRF method), phase structure (XRD method) and morphology (SEM) of Ni-P-ZrO2 and the distribution of elements in the powder were all investigated. Based on the analyses, it was found that the obtained powder contained about 50 weight % Zr and 40 weight % Ni. Phase structure analysis showed that the basic crystalline component of the tested powder is a mixed oxide of zirconium and yttrium Zr0.92Y0.08O1.96. In addition, the sample contains very large amounts of amorphous compounds (Ni-P). The mechanism to produce the composite powder particles is explained on the basis of Ni2+ ions adsorption process on the metal oxide particles. Current flow through the cell forces the movement of particles in the bath. Oxide grains with adsorbed nickel ions were transported to the cathode surface. Ni2+ ions were discharged. The oxide particles were covered with a Ni-P layer and the heavy composite grains of Ni-P-ZrO2 flowed down to the bottom of the cell.

Treatment of solitary bone cysts with allogenic bone graft and platelet-rich plasma. A preliminary report.

The treatment of solitary bone cysts remains controversial. The high recurrence rate after operative treatment calls for the search of new effective treatment methods. The aim of this study was to evaluate the outcomes of treatment of solitary bone cysts with platelet-rich plasma (PRP) and allogenic bone grafts. The study group consisted of 9 patients (4 males and 5 females) with the diagnosis of solitary bone cyst. Their mean age was 12 years and 2 months (range: 6 to 17 years). All patients were symptomatic in routine daily activities. There was a coexisting fracture within the cyst wall in three patients. The operative procedure included removal of the cyst wall soft-tissue lining and filling of the cavity with deep frozen, gamma irradiated morselized allogenic bone grafts mixed with PRP. The PRP was prepared preoperatively with the GPS System (Gravitational Platelet Separation System, Biomet Merck). In six patients with an existing or impending fracture in particularly large cysts, fixation was used. For the cysts located close to the epiphysis (2 femurs, 1 humerus) we used an IM nail or DHS. For three cysts located in the diaphyseal region of the humerus we used an Ilizarov fixator. Three cysts with lower risk of impending fracture were left without fixation. The mean follow-up period was 19.5 months (range: 12 to 30). We noted no procedure-related complications and no refracture during the observation period. Bleeding from the wound was minimal, possibly as a result of PPP use. The wounds healed without swelling or excessive scar formation. After 12 months all the cysts were completely filled with new bone and were staged as Neer stage I. All the patients were asymptomatic. The use of PRP with allogenic bone grafts appears as a promising method for the treatment of solitary bone cysts. Further studies on larger patients series with longer follow-up will be necessary to answer the question whether this method will provide a lower recurrence rate compared to other forms of treatment.

Technology to Produce High-Purity Anhydrous Rubidium Perrhenate on an Industrial Scale.

Technology used to produce high purity anhydrous rubidium perrhenate on an industrial scale from high purity perrhenic acid and rubidium nitrate by the ion-exchange method is described in this paper. This material is dedicated to catalyst preparation, therefore, strict purity requirements have to be fulfilled. These are satisfied by combining rubidium ion sorption on an ion exchange column and the subsequent elution of the high purity perrhenic acid solution, followed by crystallization, evaporation, purification, and drying. In the current study, rubidium and rhenium contents were found to be 22.5 wt.% and 55.4 wt.%, respectively, while contaminations were as follows: <2 ppm As, <2 ppm Bi, <5 ppm Ca, <5 ppm Cu, <3 ppm Fe, <10 ppm K, <3 ppm Mg, <5 ppm Mo, <2 ppm Na, <5 ppm Pb, and <3 ppm Zn.

Production of High-Purity Anhydrous Nickel(II) Perrhenate for Tungsten-Based Sintered Heavy Alloys.

This paper presents a method for the production of high-purity anhydrous nickel(II) perrhenate. The method comprises sorption of nickel(II) ions from aqueous nickel(II) nitrate solutions, using strongly acidic C160 cation exchange resin, and subsequent elution of sorbed nickel(II) ions using concentrated perrhenic acid solutions. After the neutralization of the resulting rhenium-nickel solutions, hydrated nickel(II) perrhenate is then separated and then dried at 160 °C to obtain the anhydrous form. The resulting compound is reduced in an atmosphere of dissociated ammonia in order to produce a Re-Ni alloy powder. This study provides information on the selected properties of the resulting Re-Ni powder. This powder was used as a starting material for the production of 77W-20Re-3Ni heavy alloys. Microstructure examination results and selected properties of the produced sintered heavy alloys were compared to sintered alloys produced using elemental W, Re, and Ni powders. This study showed that the application of anhydrous nickel(II) perrhenate in the production of 77W-20Re-3Ni results in better properties of the sintered alloys compared to those made from elemental powders.

Advances in radionuclide imaging for bone metastases.

Bone scan remains the most frequently requested investigation in any nuclear medicine department. The main reason for this is the exquisite sensivity of the bone scan for lesion detection, combined with clear visualisation of the whole skeleton. The isotope bone scan is now generally accepted as initial investigation of choice in the search for bone metastases from most tumours. 13583 bone scans for metastases were performed in our institution in 1998-2002 years. The frequency of bone metastases was highest in breast, prostate and lung cancer (53,9%, 58,6% and 29,5% respectively). Future progress depends on further advances in specificity of radiotracers and improvements of image acquisition and processing.