摘要
浙江省缙云沸石矿是我国最大的沸石矿之一。该矿主要由斜发沸石(Cp)和丝光沸石(Mdn)组成。两种沸石的交换性阳离子主要是Ca^(2+)和Na^+,其次是K^+,还含有少量的Mg^(2+)。不同阳离子型的斜发沸石对Ca^(2+)选择性大小的顺序是:Na-Cp>NH_4-Cp>K-Cp>Mg-Cp>Ba-Cp.K^+、Ca^(2+)在Na型斜发沸石上的竞争吸附可以用Gapon离子交换方程来描述,这时K^+-Ca^(2+)交换的Gapon系数约为14,表明斜发沸石对K^+具有特殊的选择性。
The extent of the promotive effect of zeolite on RP dissolution was determined by the selective adsorption power of the cations adsorbed on clinoptilolite for Ca, as well as the active phosphorus content of the RP. The effectiveness of increasing RP dissolution by clinoptilolite saturated with different exchanbeable cations follows in the decreasing order as listed below. H. AlCp>Na-Cp>NH4-Cp>K-Cp>Ncp>Mg-Cp>Ba-Cp>Ca-Cp. The above sequence was consistent with the selective adsorption power of the different cations adsorbed on the clinoptilolites for Ca ion RP. The effectiveness of applying NCp (natural clinoptilolite ) as an exchange fertilizer to increase the availability of RP at plants apparently depended both on the soil properties and on the chemical as well as the crystal characteristics of the RP used. It is worth while to note that samples of PR from different mining locations after equilibriura in wet condition with the same kind of Cp but saturated with different exchangeable cations -will yield great differences in the increments of water soluble P. It semed that the release from those having lower equilibrium pH systems released much more water soluble P than from alkaline systems ( compare data in Table 2 for PR-1 at pH V.70 with PR-2 at pH 8.58 and PR-3 at pH 8.00) . Volatilization of ammonia at alkaline media may impair the exchange of NH4 for Ca2+ in RP,so it may be considered as one of the indirect reasons to explain such a decrease of phosphate release.From the result of the laboratory experiments, it is also quite noticeable that NH4-Cp was able to increase plant available P(Bray-1) significantly in a neutral paddy soil ( Table 4. s-3 ) but on the other hand it did not show the same trend when the soil were either too acid(S-1 ) . Possible explanation for these results were postulated in the paper.
基金
国家自然科学基金
浙江省自然科学基金
关键词
斜发沸石
离子交换肥料
土壤有效磷
clinoptilolite
phosphate rock
dissolution ion-exchange fertilizer
