【摘要】 本文报告用 N-苯甲酰-N-苯基胲(BPHA)氯仿溶液萃取微克量锆,继用二甲酚橙乙醇溶液在有机相中测定之。水相中酸度和氯仿中 BPHA 量均影响萃取百分率。如 BPHA 浓度小于6毫克/毫升,酸度低(0.3—1N)时可萃取至少97%。酸度渐增,萃取率先下降,在4—5N 盐酸介质中达最低点,继又上升。如 BPHA 浓度为6毫克/毫升,则从0.3—10N 均能定量萃取锆。如另加入硫氰酸铵或硝酸铵0.1克亦能在较低浓度(2毫克/毫升)定量萃取5—100微克锆。少用 BPHA 有利于随后之光度测定。如同一锆量,其二甲酚橙络合物的颜色与 BPHA 量有关。因此作光度测定和校正曲线时应采用同量的 BPHA,二甲酚橙量亦应固定。锆能从0.3—10N 盐酸介质定量萃取,因此有可能借调节酸度而减少干扰。铝、钍、铀、铁、钴、硫酸根、酒石酸根不干扰。毫克量的氟离子和草酸根干扰严重。更多还原

【Abstract】 The method proposed in this communication consists of the separation of microgram amounts of zirconium by extraction with N-benzoyl-N-phenylhydroxylamine(BPHA) in chloroform and the direct determination of zirconium with ethanolic Xylenol Orangesolution in the organic phase.The effect of acidity of aqueous media and amount of BPHA used upon the per-centage of extraction of zirconium can be seen in Fig.2(in the Chinese text).From0.3 to 1 N hydrochloric acid media,at least 97 percent of zirconium is extracted.ForBPHA concentration less than 6 mg/ml,the percentage of extraction decreases with in-creasing acidity,reaches a minimum when the hydrochloric acid concentration is 4—5 N,and then increases again.For BPHA concentration of 6 mg/ml,zirconium can be quan-titatively extracted into organic layer from 0.3 to 10N hydrochloric acid media.Thesame holds also for lower BPHA concentration(for example 2 mg/ml),provided am-monium thiocyanate or nitrate(0.1 gm)is also present in the aqueous phase(Fig.2).The addition of these ammonium salts is favoured because they reduce the amount ofBPHA required,which,in turn,is advantageous for the subsequent photometric deter-mination of zirconium.It has been also verified experimentally that 5 to 100 μg ofzirconium can be quantitatively extracted into (a)5 ml of BPHA (1mg/ml)solution from10 ml of 1 N hydrochloric acid media,(b)5 ml of BPHA (2 mg/ml)solution from 10 mlof 4 N hydrochloric acid media containing 0.1 gram of ammonium thiocyanate,and (c)as b but containing 0.1 gram of ammonium nitrate instead of thiocyanate.For the same amount of zirconium,the optical density of its Xylenol Orange com-plex varies with the amount of BPHA in chloroform layer(Fig.1).The more BPHAin organic phase,the less the optical density,while the time needed to develop thecolour is also prolonged.Therefore it is necessary to use the same(and preferably small)amount of BPHA for extraction in the case of unknown and in making the calibrationcurve.The amount of Xylenol Orange used in photometric determination must be keptconstant too. As the percentage extraction of titanium and niobium increases with increasingacidity,it is preferable to use low acidity to extract zirconium in the presence of theseelements.There are also elements which are extracted from low acidity media.If ex-traction takes place from 1 N hydrochloric acid media,the amount of tin(Ⅳ)allowedto be present is 30 μg,while from 6 N hydrochloric acid media,300 μg will be allowed.The extraction of zirconium with BPHA is possible over a wide range of acidity(0.3—10 N hydrochloric acid),hence the optimum acidity can be chosen according to the natureof foreign ions present.In extraction of microgram amounts of zirconium from 1 Nhydrochloric acid media,the presence of twice so much of titanium and niobium as zir-conium is allowed.Larger amounts of aluminium,cobalt,copper(masked with thio-urea),iron(Ⅲ)(reduced with ascorbic acid),thorium,uranium,sulfate and tartrate donot interfere.Milligram amounts of fluoride and oxalate interfere seriously.更多还原