磷钾伴生矿生产化肥过程中铝元素的资源化利用

发布时间：2018-04-26 00:15

  本文选题：磷钾伴生矿 + 三聚磷酸铝　； 参考：《武汉工程大学》2015年硕士论文

【摘要】：我国可溶性钾盐资源缺乏且磷矿绝大部分属于中低品味,致使农业施用化肥多氮少磷缺钾现象严重。而以钾长石(K2O·Al2O3·6SiO2)为代表的难溶性钾资源却分布广泛、储量极其丰富。湖北宜昌地区磷钾伴生矿储量丰富,其组成主要包括胶磷矿、钾长石和石英等物质组成。合理开发、利用该地区磷钾伴生矿资源,有利于缓解我国水溶性钾资源的不足和提升磷资源综合利用率。利用磷钾伴生矿酸浸液生产化肥,除杂得到的粗氢氧化铝若作为废料丢弃是一种资源的浪费,且会对环境造成危害,对其回收利用,有利于提高磷钾伴生矿综合利用的经济性。本文探索了一条回收利用酸浸液生产化肥除杂产生的粗氢氧化铝,提纯制备氢氧化铝,合成防锈颜料三聚磷酸铝的工艺线路。主要工作包括:磷钾伴生矿酸浸液净化得到粗氢氧化铝、粗氢氧化铝碱溶提纯制备氢氧化铝以及利用提纯的氢氧化铝与磷酸合成防锈颜料三聚磷酸铝。并结合化学分析、X-射线衍射仪(XRD)以及傅里叶红外光谱仪(FT-IR)对合成的产品进行了表征分析。主要结论如下:(1)利用磷钾伴生矿酸浸液生产化肥,直接用氨水调节中和,溶液中杂质离子以及氟硅酸盐与氨水反应,形成沉淀进入粗氢氧化铝中,导致粗氢氧化铝中氧化铝与二氧化硅的质量比(A/S)较小、且酸浸液中含有大量的氯离子,不利于后续铝元素的回收利用以及低氯氮磷钾复合肥的制备,因此需要对酸浸液进行除氯和除硅的处理。本文采用添加硫酸蒸馏除氯的方法,磷钾伴生矿反应后的酸浸液,加入计量后的硫酸在70℃、0.09 MPa(真空度)下蒸馏50 min,此时酸浸液体积剩余8%左右,经测定酸浸液中80%左右的氯离子被去除。除氯后的酸浸液,加入一定量的蒸馏水和双氧水,采用氧化絮凝法除硅。结果表明经过除硅后,粗氢氧化铝中Al2O3含量由17.68%提高至23.04%,SiO2含量由10.28%下降到4.63%,A/S由1.71提高至4.97。(2)研究了碱溶工艺条件对氧化铝溶出率的影响,结果表明:粗氢氧化铝与3mol/L氢氧化钠按液固比5在90℃下反应40 min,氧化铝的溶出率可达到72%。铝酸钠溶液利用CaO对进行脱硅处理,净化后的铝酸钠溶液分别采用NaAlO2-HNO3法和制备的氢氧化铝。研究结果表明,NaAlO2-HNO3法和铝酸钠溶液种分法制备氢氧化铝纯度均≥96%。(3)以制备的氢氧化铝和分析纯磷酸为原料,对影响合成防锈颜料三聚磷酸铝的主要因素进行了研究,得到优化条件为:原料(P2O5与Al2O3摩尔比)为3.0,中和反应时间为60 min,中和反应温度为70℃,缩合反应温度290℃,缩合反应时间为4 h。化学分析结果、FT-IR、XRD表明制备的产品是三聚磷酸铝且主组分含量符合Q/HGY07-1999的要求。
[Abstract]:The lack of soluble potassium salt resources in China and the fact that most of the phosphate rocks belong to medium and low taste have caused a serious phenomenon of the agricultural application of chemical fertilizer with more nitrogen and less phosphorus and less potassium. The insoluble potassium resources, represented by K _ 2O Al2O3 _ 6SiO _ 2, are widely distributed and rich in reserves. Phosphorus and potassium associated deposits are abundant in Yichang area of Hubei Province, and their composition mainly includes mineral composition of colloid phosphate, potassium feldspar and quartz. Reasonable exploitation and utilization of phosphorus and potassium associated mineral resources in this area will help to alleviate the shortage of water-soluble potassium resources and improve the comprehensive utilization rate of phosphorus resources in China. It is a waste of resources to produce chemical fertilizer by acid leaching solution associated with phosphorus and potassium, and if the coarse aluminum hydroxide is discarded as waste material, it will cause harm to the environment, and the recovery and utilization of it will help to improve the economy of comprehensive utilization of phosphorus and potassium associated minerals. In this paper, a technological route of recovering crude aluminum hydroxide from chemical fertilizer and impurity removal, purifying and preparing aluminum hydroxide, and synthesizing antirust pigment aluminum triphosphate has been explored. The main work includes: purification of phosphorus-potassium acid-leaching solution to obtain coarse aluminum hydroxide, alkali purification of crude aluminum hydroxide to prepare aluminum hydroxide, and synthesis of antirust pigment aluminum triphosphate from purified aluminum hydroxide and phosphoric acid. The synthesized products were characterized and analyzed by chemical analysis X- ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FT-IR). The main conclusions are as follows: (1) the chemical fertilizer is produced from phosphorus-potassium acid-leaching solution, which is directly neutralized with ammonia water, and impurity ions in the solution and fluorosilicate react with ammonia to form precipitates into coarse aluminum hydroxide. As a result, the mass ratio of alumina to silica in crude aluminum hydroxide is smaller than A / S, and there is a large amount of chlorine ions in the acid extract, which is not conducive to the subsequent recovery of aluminum and the preparation of low chloro nitrogen, phosphorus and potassium compound fertilizer. Therefore, it is necessary to remove chlorine and silicon from acid leachate. In this paper, by adding sulfuric acid distillation to remove chlorine, the acid leachate of phosphorus and potassium associated with ore reaction is distilled for 50 min at 70 鈩，

本文编号：1803618