摘要
为解决铬矿熔样过程中难熔于熔剂、稀释比大以及产生气泡导致飞溅等问题，研究并绘制了三氧化二铬在不同熔剂体系中的溶解度曲线；考察了铬的不同价态对溶解度的影响。研究发现，铬矿难熔的原因主要是由于弱酸性三氧化二铬易熔于碱性熔剂，不易熔于酸性的硼酸盐熔剂；而六价铬由于碱性更强，更易熔于弱酸性的偏硼酸锂熔剂中。依据实验结果，提出采用质量比为3：1的四硼酸锂与硝酸钠混合熔剂，在1150℃熔融制样15min，用X射线荧光光谱仪（XRF）对铬矿中铬、铁、硅、铝、磷元素进行同时测定的方法。对两个铬矿标准样品进行测定，测定值与认定值一致，相对标准偏差（n=6）为0．36％～1．4％。较传统制样方法，实验用熔样方法降低了稀释比，克服了偏磷酸盐熔样无法测定磷，硼酸盐熔样易结晶、无法精确测定铬等问题。
There were some problems during the fusion of chromium ore sample such as low solubility in flux,large dilution ratio and splashing caused by bubbles.In order to solve these problems,the solubility curve of chromic oxide in different flux systems was investigated and prepared.The effect of chromium valence on the solubility was studied.It was found that the infusibility of chromium ore was due to that the weakly acidic chromic oxide was easily fusible in alkaline flux but infusible in acidic borate flux,while the hexavalent chromium was fusible in weakly acidic lithium metaborate due to its stronger alkalinity.Based on the experimental results,the following sample fusion condition was proposed:the mixed flux of lithium tetraborate and sodium nitrate(in mass ratio of 3∶1)was used;the sample was fused at 1 150 ℃ for15min;finally,the content of chromium,iron,silicon,aluminum and phosphorus in chromium ore was simultaneous determined by X-ray fluorescence spectrometry(XRF).Two standard samples of chromium ore were determined,and the found results were consistent with the certified values.The relative standard deviations(RSD,n=6)was between 0.36% and 1.4%.Compared to the traditional sample preparation method,the dilution ratio in proposed method was reduced.It solved some problems,for example,incapable determination of phosphorus for metaphosphate flux,easy crystallization of borate flux,and inaccurate determination of chromium.
出处
《冶金分析》
CAS
CSCD
北大核心
2015年第7期27-31,共5页
Metallurgical Analysis
基金
河北省科技条件建设项目(12966912D)
关键词
铬矿
熔融制样
X射线荧光光谱法
溶解度曲线
酸度指数
chromium ore
fusion sample preparation
X-ray fluorescence spectrometry
solubility curve
acidity index
