Zirconium cleaning

Zirconium is a highly active metal which, like aluminum, seems quite passive because of its stable, cohesive, protective oxide film which is always present in air or water. Massive zirconium does not bum in air, but oxidizes rapidly above 600°C in air. Clean zirconium plate ignites spontaneously in oxygen of ca 2 MPa (300 psi) the autoignition pressure drops as the metal thickness decreases. Zirconium powder ignites quite easily. Powder (<44 fim or—325 mesh) prepared in an inert atmosphere by the hydride—dehydride process ignites spontaneously upon contact with air unless its surface has been conditioned, ie, preoxidized by slow addition of air to the inert atmosphere. Heated zirconium is readily oxidized by carbon dioxide, sulfur dioxide, or water vapor. 

Test method for sandwich corrosion test Recommended practice for preparing, cleaning, and evaluating corrosion test specimens Practice for aqueous corrosion testing of samples of zirconium and zirconium alloys Test method for corrosion testing of products of zirconium, hafnium and their alloys in water at 633 K or in steam at 673 K [metric] Recommended practice for conventions applicable to electrochemical measurements in corrosion testing... 

Alkynylzinc bromides 133 are also cleanly hydrozirconated with Cp2Zr(H)Cl leading to 1,1-bimetalloalkenes of zinc and zirconium (134), which react smoothly with aldehydes to afford allenes in satisfactory yields (Scheme 7.40) [232,233]. 

The bulk flotation can be accomplished with the addition of small doses of oleic acid plus oxidized emulsion of fuel oil. The fuel oil is treated with 10% solution of NaOH at a temperature of 60-80°C for 1 h. The following method was used for rutile-zircon separation the concentrate was thickened, followed by heat conditioning to 60°C. After the heat treatment, the zircon was floated without the addition of collector. The zirconium tailing is the rutile concentrate. The zircon concentrate was thickened, followed by gravity cleaning. In some cases, the heat-treated pulp is washed before zircon flotation. The following metallurgical results were obtained ... 

Degraded TBP process solvent is typically cleaned by washing with sodium carbonate or sodium hydroxide solutions, or both. Such washes eliminate retained uranium and plutonium as well as HDBP and H2MBP. Part of the low-molecular-weight neutral molecules such as butanol and nitrobutane, entrained in the aqueous phase, and 90-95% of the fission products ruthenium and zirconium are also removed by the alkaline washes. Alkaline washing is not sufficient, however, to completely restore the interfacial properties of the TBP solvent, because some surfactants still remain in the organic phase. 

Zirconium columns kits for preparing affinity columns have been recently released by ZirChrom. They contain an activated linker that can be reacted with the target compound in the prepacked column to prepare the affinity column in situ. Generally, when an affinity column is made, the column must be dedicated to only that one separation. If you have six different affinity separations to make, you must buy six columns. But with these zirconium column kits, the affinity head can be stripped off in the column, the column cleaned, the linker reactivated, and a new affinity column created with a new affinity target without unpacking and repacking the column. This should open create new interest in affinity separations. 

A variety of new ligand designs and ligand combinations were used in attempts to mimic some properties of the ubiquitous bent metallocene environment at the early metal centers consequently, some of these systems were used in the further development of butadiene zirconium chemistry. The pyridine based chelate zirconium dichloride complex 43 cleanly formed the butadiene complex 44 upon treatment with butadiene-magnesium. Its structure shows that the C4H6 is arranged perpendicular to the chelate ligand plane. Complex 44 inserts one equivalent of an alkene or alkyne to form the metallacyclic 7i-allyl system 4545 (Scheme 13). 

Metal salts may be used in the treatment of wool. Flame methods for the determination of aluminium [185], barium, chromium, copper, mercury, strontium, tin, zinc [186] and zirconium [187] in wool have been published. Standard additions to wool cleaned by soaking and washing it with disodium EDTA (800 ml of 0.5 M for 30g wool with soaking for 3 days and double washing) was used as the calibration technique. This compensated for interferences from hydrochloric acid and amino-acids. The samples were equilibrated to a constant humidity for 24 h and then 0.3 g sealed with 5 ml of constant boiling point hydrochloric acid in a glass tube. The tubes were placed in an oven at 110UC for 20 h. The nitrous oxide/acetylene flame was used for the determination of aluminium and zirconium. Sulphate, phosphate, citrate and silicate have been found to interfere in the determination of titanium and zirconium in fire-proofed wool [188], These flame... 

The reactivity of zirconium imido complexes supported by a dibenzotetraaza[14]annulene (taa) macrocycle ligand toward a range of unsaturated substrates has been examined. Reaction with t-butyl isocyanate cleanly generated the cycloaddition product Zr N(2,6-( -Pr)2C6H3)C(0)N(t-Bu) (Me4taa) (equation 21). ... 

---