【作者】 刘杰；

【导师】 韩跃新； 印万忠；

【作者基本信息】 东北大学 ， 矿物加工工程， 2009， 博士

【摘要】 钾肥是农业中不可缺少的常用三大肥料之一。我国可溶性钾矿资源储量少,且分布极不平衡。相对来说,不溶性钾矿资源却比较丰富,而且分布广泛。利用不溶性含钾盐矿制造钾肥,开发新型钾盐加工和提取技术,因地制宜的开发利用不溶性钾矿资源生产钾肥或在矿产综合利用中制取钾肥,一直是国内外较为重要的研究课题。这不仅是一条解决目前我国缺少可溶钾资源现状的有效途径,还可以收到良好的经济效益和社会效益。运用现代大型测试分析仪器,如扫描电镜、EDS能谱分析、X射线衍射、热分析、ICP等,对辽宁省朝阳地区的富钾页岩进行了鉴定和分析。并采用MLA对富钾页岩的工艺矿物学性质进行了系统深入的研究。分析得出此种页岩中的含钾矿物主要以独立矿物的形式存在,其中主要的含钾矿物为钾长石,其次为白云母(绢云母)、伊利石和黑云母及少量的绿泥石,还含有石英等脉石矿物。其中约80%的钾赋存于钾长石之中,约20%的钾赋存于白云母、伊利石和黑云母等云母类矿物之中。利用晶体化学的基本原理,并结合价键理论对富钾页岩中主要含钾硅酸盐矿物的化学键特征参数进行了理论计算。依照价键理论分析可知构成微斜长石和白云母骨架结构的Si-O和Al-O键的化学性质稳定。硅酸盐晶体结构的研究和分析结果表明具有架状结构的钾长石和层状结构的云母类矿物的晶体结构相对稳定,其晶体结构中的钾与氧主要以离子键的形式相结合,这种结合力相对比较稳定。分别采用热分解法和高温高压水热法提取该页岩中的钾,并对这两种工艺的提钾过程进行了深入系统的研究和探讨。用实际晶体最强衍射峰的主要相关参数来定性地表征富钾页岩中主要含钾矿物经热分解法或高温高压水热法处理后其晶体结构的变化趋势。本文主要研究了两种热分解提钾工艺：富钾页岩经NaOH溶液预处理后焙烧酸浸提钾工艺和以KOH为焙烧助剂直接焙烧酸浸提钾工艺。通过对影响这两种焙烧酸浸提钾过程的主要因素的研究和分析,确定了在适宜的反应条件下,钾的浸出率分别为88.08%和99.99%。在适宜的条件下,以KOH为焙烧助剂,页岩经焙烧酸浸后,浸渣中铝的去除率为97.6%,同时获得微观性能较好的白炭黑产品。利用XRD.SEM和热分析等手段,对经质量配比为m(NaOH):m(页岩)=0.7的NaOH预处理后的混和物料的焙烧过程和以质量配比为m(NaOH):m(页岩)=1的KOH为焙烧助剂的富钾页岩的焙烧过程的反应机理进行了深入系统的研究。研究结果表明,在碱性条件下,焙烧提钾的反应机理是在强碱的作用下含钾硅酸盐矿物逐步分化的过程。在这两种不同热分解工艺中,碱的处理方式和碱的相对含量不同,焙烧过程中页岩中主要含钾硅酸盐矿物的分解产物不同。页岩经NaOH溶液预处理后的焙烧提钾过程的主要反应机理是在高温和碱性条件下,不溶性的钾长石和云母等含钾矿物转变为酸溶性的钾霞石的过程。而以KOH为焙烧助剂的热分解过程的主要反应机理是KOH熔融分化钾长石和云母等含钾矿物,并转变为K2SiO3、K2Al2O4等成分。同时,对以上两种焙烧酸浸过程中可能发生的主要反应进行热力学计算和分析,确定了反应发生的可能性。对以上两种热分解过程的动力学研究表明以上两种碱性条件下的热分解过程均符合金斯特林格扩散控制动力学模型。利用XRD和SEM等手段对热分解后焙烧产物的酸浸提钾过程的反应机理进行研究。经NaOH预处理后,600℃焙烧产物的酸浸过程是焙烧产物中的主要含钾物相钾霞石的酸解过程。同时,结合扩散双电层等理论对以KOH为焙烧助剂700℃焙烧产物的酸浸机理进行分析,研究表明此酸浸过程的主要反应机理为焙烧产物中的K2SiO3在过量的硫酸作用下形成原硅酸溶胶,溶胶进一步沉聚或絮凝生成SiO2·nH2O沉淀。通过考察各因素对高温高压水热法提钾过程的影响,在适宜的水热条件下钾的浸出率可以达到95%以上。通过对其浸渣的XRD和SEM分析并结合过渡态理论,确定了水热反应提钾过程的主要反应机理是CaO逐渐“浸蚀”并分解富钾页岩中的主要含钾物相,进而转变为新生成物相,使钾以K+离子的形式进入溶液中。同时,对水热系统中可能发生的主要反应进行了热力学分析和计算,确定了主要反应发生的可能性。动力学研究表明高温高压水热反应动力学过程符合化学反应控制模型。在对整个提钾过程研究的基础上,本文分别设计了热分解法和高温高压水热法综合利用富钾页岩的工艺模型。首次提出了以KOH为焙烧助剂焙烧酸浸法综合利用富钾页岩的工艺流程,通过此流程可获得符合国家标准的白炭黑、K2SO4、Al(OH)3和Fe2O3产品。同时,利用高温高压水热法处理富钾页岩可得到碳酸钾产品并可综合利用其尾渣生产水泥填料。本研究弄清了辽宁朝阳富钾页岩的特性,对从富钾页岩中提钾进行了卓有成效的探讨,本研究成果对我国钾资源的可持续开发与利用具有一定的指导意义。更多还原

【Abstract】 Potash fertilizer is the one of three kinds of necessary fertilizers in agriculture widely. The reserve of soluble potash resources is lack and the distribution of that is imbalance seriously in China. Comparatively, there are abundant and comprehensive insoluble potash resources in our country. It is important to research and develop new processes and technologies of potassium extraction from local insoluble ore with potassium and utilize the main components in ores comprehensively, which can solve current serious problems of the shortage of soluble potash resources in China effectively and bring economic and social benefits.Chemical composition, mineral components and contents, mineral association and mineral grain size distribution of potassium-rich shale from Chaoyang of Liaoning was studied by means of scanning electronic microscope (SEM), EDS, x-ray diffraction (XRD), thermal analysis (DTA), ICP, infrared spectrum(FT-IR), and mineral liberation analyzer (MLA). Occurrence state of potassium in potassium-rich shale was determined. Main minerals with potassium in the shale were potassium feldspar, muscovite, illite, biotite and a small number chlorite and the main gangue mineral was quartz. About 80% of potassium in the shale exited in the potassium feldspar and there was 20% of potassium in such mica with potassium as muscovite, illite and biotite.According to the basic principle of crystal chemistry and valence-bond theory, characteristic parameter of chemical bond and crystal structure of main silicate minerals with potassium in the shale were calculated and analyzed. The results showed that chemical properties of the Si-O bond and Al-O bond of the skeletal structure of microcline and muscovite were stable relatively. Potassium in silicate crystal structure was stably attached to oxidize by ionic bond.Processes of potassium extraction from potassium-rich shale were studied in the pyrolytic system and the hydro-thermal system respectively. Furthermore, mechanisms of potassium exraction were determined.Two different kinds of pyrolytic techniques were used on the base of different alkali-treated mode-roasting the mixed materials after preprocessing potassium-rich shale with NaOH and roasting potassium-rich shale directly with KOH. Main influence factors on potassium extracting rate in the both of pyrolytic procedures were studied. The results showed that the former potassium extraction ratio was 88.08% and the latter was up to 99.99% under optimum conditions. And under the latter optimum conditions, aluminum removal ratio of filter residue was 97.6% and silica hydrated with good micro-properties was obtained.The mechanism of potassium extraction in the both of roasting techniques, roasting mixed materials after preprocessing potassium-rich shale with NaOH at mass ratio of NaOH to shales being 0.7 and roasting mixed materials at mass ratio of KOH to shales being 1, was studied by XRD, SEM and TG-DSC, respectively. The research results showed that the mechanism of potassium extraction in pyrolytic process was disintegrative course of silicate minerals with potassium gradually under the action of alkali. The decomposition products of silicate minerals with potassium were diverse, due to different alkali-treated modes and use level of alkali in the both of pyrolytic techniques. The former mechanism was that such insoluble minerals with potassium as potassium feldspar and mica in the shale were turned into acid-soluble kaliophilite under high temperature and a little bit alkali, and kaliophilite became the main phase in roasted products. However, the latter mechanism was that potassium feldspar and mica with potassium in the shale were melted and disintegrated to form such soluble phase with potassium as K2SiO3 and K2Al2O4. Calculation and analysis of thermodynamics showed that main chemical reactions in two different kinds of pyrolytic processes could perhaps occur. The analysis of kinetics determined that both of pyrolytic processes were controlled by diffusion and model equations were in accordance with dynamical equation of Crank-Ginstling-Braunshtein.The acidic mechanism of roasted products in both of pyrolytic techniques during the process of acid-leaching was studied by XRD and SEM. The acidic mechanism of roasted products after roasting mixed materials with NaOH at 600℃was that under acidic condition, kaliophilite with potassium was dissolved to form K+, Al3+etc. And, by the theory of double electrode layer, The acidic mechanism of roasted products after roasting mixed materials with KOH at 700℃was that under the action of Excessive acid, K2Si03 turned into colloidal silica, and then colloidal silica was agglomerated to produce precipitate of SiO2·nH2O.The research results of influnces of main factors on potassium extraction in hydro-thermal system showed that potassium extraction ratio was up to 95%under optimum conditions. By XRD and SEM analysis for leaching residue and transition state theory, the mechanism of potassium extraction in hydrothermal system was that minerals with potassium in potassium-rich shale were decomposed and turned into new products and potassium in raw samples entered into solution as K+. Calculation and analysis of thermodynamics showed that main chemical reactions in the system could perhaps occur. The analysis of kinetics determined that the model equation to be controlled by chemical reaction was abtained.According to the above experimental results and mechanism analysis, this paper put forward the technical proposal of comprehensive application of potassium-rich shale in both of pyrolytic and hydro-thermal system. Silica hydrated, K2SO4, Al(OH)3 and Fe2O3 could be produced in the processes of comprehensive application of potassium-rich shale with KOH by pyrolytic method, which met the requirements of national standards. During processes of hydrothermal reaction, potassium in potassium-rich shale could form K2CO3 product and the leaching residue was a kind of cement padding.In this paper, the characteristics of potassium-rich shale from Chaoyang of Liaoyang and the processes of potassium extraction were determined. The research results were important to develop and practise continuable utilization of resources with potassium.更多还原