【作者】 黄珂；

【导师】 王光龙；

【作者基本信息】 郑州大学 ， 化学工艺， 2012， 硕士

【摘要】 在我国这样一个钾资源非常缺乏的国家,能够合理利用以钾长石为主的非水溶性钾矿资源,具有非常重要的经济意义。本文主要研究了低温条件下钾长石共酸提钾的工艺,采用纯试剂模拟磷矿与钾长石共酸提钾,在排除磷矿反应活性、成矿原因等因素导致结果差异的情况下,对磷矿的普遍适用性进行研究,并初步探讨钾长石共酸提钾过程的机理与动力学,将钾长石系统钾含量分析的两种方法做了对比,以硫酸脲代替硫酸作为酸解液,与钾长石反应,对该体系工艺进行了优化。通过采用纯化学试剂模拟磷矿与钾长石共同反应,分析各种组分对钾的溶出率的影响,初步探讨其过程机理,实验结果为：各因素对钾溶出率的影响顺序由大到小为：氟化钙质量、氧化镁氧化钙质量比、磷酸三钙质量,较优化的各成分比例为：钾长石：磷矿0.8：1、磷矿：磷酸三钙：氟化钙1：0.5：0.1,氧化镁和氧化钙质量比在1：1时钾溶出率比较理想。在常见磷矿氟含量范围内,钾的溶出率随氟含量的增大呈现单调增长的趋势。通过对磷矿的普遍性的探讨可得出,钾长石提钾机理分为两步：第一步为模拟磷矿和硫酸反应产生氢氟酸将钾长石结构破坏；第二步为钙镁离子进入钾长石内部发生置换反应进行钾的提取。动力学分析表明：用纯试剂与钾长石共酸提钾的过程与磷矿同钾长石共酸体系提钾的动力学分析相一致,此反应既不是简单的物理控制过程或化学反应控制,而是属于固相扩散控制过程。鉴于该工艺系统的特殊性,对钾含量分析的两种方法在这种体系中的适用性进行对比实验,通过对所得样品分别进行两种方法的分析,结果表明四苯硼钠重量法测得的结果比容量法测得的结果偏高,重量法测钾比较准确,平行实验之间的差距很小。EDTA加入量对重量法和容量法分析结果的影响均较大,重量法中若EDTA的量偏少,就会引起实验结果偏大,在溶出率较高(大于95%)的情况下,若EDTA加入量不足,甚至可能出现溶出率大于100%的情形,容量法中EDTA加入量不足会导致滴定至变色后,过一段时间又恢复至先前的颜色,使结果分析失败。基于酸法工艺的现状和对该系统机理探讨的基础上,从节能环保的角度出发,通过对硫酸脲溶液与钾长石反应工艺条件优化,分别考察了反应时间、反应温度、硫酸用量与质量分数,尿素硫酸比对钾溶出率的影响,获得了硫酸脲与钾长石反应的较优的工艺条件,虽然与钾长石-磷矿-硫酸体系相比,钾长石-磷矿-硫酸脲体系所得到的钾溶出率有所降低,但具有使硫酸与磷矿反应缓和,氟含量排放减少,降低环境污染,降低能耗的优点。更多还原

【Abstract】 In our country it is very lack of potassium mineral resources, so the rational use of non-water-soluble potassium mineral resources especially the potash feldspar has a very important economic significance. This paper mainly studies research about potassium extraction from potash feldspar with acids at the low temperature, using the pure chemical reagents to imitate phosphorite for potassium extraction from potash feldspar with acids, in the case of exclusion of reactivity,metallogenic reason of phosphorite etc on leads to the results of differences, study the universal applicability of the phosphorite, conducted a preliminary study on the mechanism and kinetics of the process of extracting potassium from potash feldspar, the two methods of the potassium content analysis of potash feldspar system are compared, instead of sulfuric acid as the acid hydrolyzate, and K-feldspar reaction to sulfuric acid urea,the system process was optimized.Through the use of pure chemical reagents and potash feldspar reaction, analysis of the effect about various components on the dissolution rates of potassium, the mechanism of the process is preliminary discussed, the experimental results:the order of descending of various factors on the potassium dissolution rates is:the quality of calcium fluoride, mass ratio of magnesium oxide and calcium oxide, the quality of tricalcium phosphate, more optimized composition ratio is:K-feldspar: phosphorite0.8:1,phosphorite:tricalcium phosphate:calcium fluoride1:0.5:1, the mass ratio of magnesium oxide and calcium oxide is1:1. Within the scope of the common fluoride content of phosphorite, the dissolution rate of potassium showing monotone increasing trend with increasing fluoride content.Through the discussion of the universality of phosphorite it can obtain that:the mechanism of potassium extraction from potash feldspar can be divided into two steps:the first step is the reaction of phosphorite and sulfuric acid which produces hydrofluoric acid and then hydrofluoric acid destroy potassium feldspar’s structural; the second step is the replacement reaction that calcium and magnesium ions into the potash feldspar internal replaces potassium ions. Dynamics analysis shows that:use pure reagent or phosphorite for potassium extraction from potash feldspar with acids the dynamics analysis is consistent, neither a simple physical control process or chemical reaction control, but belongs to the solid-phase diffusion-controlled process.Given the special nature of the process, the comparative experiment is conducted for the applicability of such a system of potassium content analysis,through the analysis with two methods of the samples, the results show that the measured results of the sodium tetraphenylborate gravimetric method is higher than the volumetric method’s, the sodium tetraphenylborate gravimetric method is more accurate, the gap between the parallel experiment is very small. The addition amount of EDTA has a bigger impact on the analysis results of gravimetric method and volumetric method, if the addition amount of EDTA is less than normal gravimetric method, it will cause larger experimental results, when the dissolution rate is higher (more than95%), if the addition amount of EDTA is insufficient, perhaps even the dissolution rate is greater than100%, if the addition amount of EDTA is not enough for volumetric method, it can lead to the end color return to the previous color after a period of time and then the analysis is failure,Based on the status of the acid process and mechanism discussion of the system, starting from the point of view of energy saving and environmental protection, through the optimization of the process conditions of the urea solution of sulfuric acid and potassium feldspar reaction, reaction time, reaction temperature, amount of sulfuric acid and the mass fraction of urea, mole ratio of urea and sulfuric acid were investigated to the influence potassium dissolution rate, access to the optimal process conditions,compared with the system of potash feldspar-phosphorite-sulfuric acid, though the dissolution rate of the system of potash feldspar-phosphorite-urea sulfuric acid decreased, it has some advantages such as:the reaction of sulfuric acid and phosphorite became ease, the emission of fluorine, content environmental pollution and the energy consumption are reduced.更多还原