土壤氧化铁的高梯度磁场分离技术的研究

STUDY OF HIGH-GRADIENT MAGNETIC SEPARATION (HGMS) IN SOIL IRON OXIDES

以中南地区几种主要地带性土壤为材料，探讨了高梯度磁场（ＨＧＭＳ）分离土壤氧化铁的技术。结果表明：土壤胶体经ＨＧＭＳ处理，氧化铁的浓缩倍数与提取率呈负相关。以２％的ＮａＯＨ溶液为分散剂，在较低磁场强度下（０．９Ｔ），以４００ｍｌ／ｍｉｎ的流速将胶体悬液通过双面塑料载丝盒，氧化铁的浓缩倍数较大；以２％Ｎａ２ＣＯ３溶液为分散剂，或以２％ＮａＯＨ溶液为分散剂，在较强的磁场强度下（１．２Ｔ），以１００ｍｌ／ｍｉｎ流速将胶体悬液通过双面铁片载丝盒，磁性部分的提取率较大。氧化铁含量低的土壤胶体，用ＨＧＭＳ处理。

Optimum conditions of using HGMS for scveral zonal soils in central and southern China were investigated by means of XRD and chemical analysis methods. Results indicated that the concentrating times of iron oxides by HGMS treatment was negatively correlated to the ratio of magnetic fraction extracted. Concentrating times of iron oxides was high in samples which were dispersed in dilute NaOH solution and were passed through the filter with two sheets of plastic in a flow rate of 400 ml/min and under magnetic flux density(MFD)of 0. 9 Tesla. By contrast, the ratio of magnetic fraction extracted in samples which were dispersed in dilute Na2CO3 or NaOH solution and were passed through the filter in two sheets of silicon-steel in a flow of 100 ml/min and under MFD of 1.2 T was high. For the soil with low content of iron oxides,the concentrating times of iron oxides was relatively bigger.