石煤钠盐焙烧气氛对钒转化的研究

STUDIES OF ATMOSPHERE EFFECT ON TRANSFORM OF VANADIUM IN SALT ROASTING OF STONE COAL

石煤钠盐焙烧是复杂的气、液、固多相化学反应,焙烧气氛对钒焙烧转化率有重要影响。本文在钒价态研究工作的基础上,研究了在氧化—氯化焙烧下,提高气相中HCl或Cl_2分压,使钒转化率有不同程度的提高,小试表明能提高5～20％,半工业生产试验提高5.4％。该技术简易可行,实用性强,具有较好的经济效益。 本文对氧化—氯化焙烧的技术条件、焙烧温度、时间、含碳量及钠盐配比等作了全面研究。通过气体成分分析,焙砂浸出液成分分析和物相分析鉴定,对氧化—氯化焙烧提高钒焙烧转化率的机理作了探讨。

The salt roasting of stone coal is a complex multiphase chemical reactions. The atmosphere in roasting process has an important effect on the roasting efficiency of vanadium. In this paper, based on the studies of the oxidation of vanadium in roasting, the roasting temperature and time, the quantity of carbon contained, the mixture ratio of NaCl, the atmospheric condition and other factors that may affect the roasting efficiency have been investigated more sufficiently. The experimental results show that, the PHCL and Pcl2 under the oxidution-chloration atmosphere are several times over that under the oxidation atmosphere, and the roasting ef-ficiency of vanadium, at the same time, increases by 5~ 20%. By means of analysis of the chloration gas, the leached solution and the phase of residue, it is supposed that the obvious increase of PHCLand Pcl2 is favourable to raise the roasting efficiency of vanadium in two ways: 1. It can accelerate oxidizing reaction of vanadium and prevent the forming of sodium and calcium silicate eutectoid that may tie up the vanadium. 2. It can chloridize the vanadium and change V2O5 from collective state to free state that is advantageous to extract. Further pilot-plant test has also approved the oxidation-chloration roasting method, with this method, the roasting efficiency of vanadium increases by a factor of 5.4%. The oxidation-chloration roasting technique is simple and feasible, it has good economical benefit and application prospect.