【作者】 丁亚卓；

【导师】 印万忠；

【作者基本信息】 东北大学 ， 矿物加工工程， 2010， 博士

【摘要】 石英是一种物理性质和化学性质均十分稳定,用途十分广泛的矿产资源。普通石英砂应用在玻璃、陶瓷、橡胶、铸造等领域。而高纯度的石英砂SiO2含量在99.95%以上或者更高,主要应用在高新技术产业如航空航天、生物工程、高频率技术、电子技术、光纤通信和军工等领域。自然界中只有优质水晶(一级、二级水晶)可以满足要求,而本身储量有限,加上全球光纤通讯和半导体工业的飞速发展,使之逐渐趋向枯竭。因此利用各种分选提纯的手段从石英砂资源中分离高纯度的石英砂日前成为研究的重点。石英的提纯是一项重要的浮选理论与实践课题。石英常与其它硅酸盐矿物伴生,主要为长石类矿物,由于同属于架状硅酸盐矿物,解离后的表面特性也很相似,因此长石和石英之间的浮选分离技术难度较大。目前,对这一体系的浮选研究主要侧重于阴阳离子混合捕收剂在酸性条件下对长石捕收作用研究,和混合酸对石英矿的浸出研究,而对于获得较高纯度的石英,均需要挑选高品位的原矿用于提纯,这样就限制了高纯度石英的原料。为了从普通石英砂中制备高纯度石英,就需要对这一体系进行系统的试验研究。研究中首先通过大量的试验,以长石和石英的纯矿物为研究对象,在阳离子捕收剂十二胺体系中,寻找长石和石英的选择性活化剂和抑制剂。主要针对有机小分子抑制剂进行了筛选,找到了十二胺体系下,长石和石英分选的高效选择性抑制剂——草酸。并在单矿物以及人工混合矿浮选分离中取得了较好的指标。在试验中首次发现了细粒长石对长石和石英浮选分离的交互式影响,并通过合理的药剂制度减轻了这种交互式影响所带来的不利后果,提高了浮选的指标。对实际矿石的研究结果表明：以朝阳某地原矿SiO2品位93.01%的石英矿为原料,以草酸为调整剂,十二胺为捕收剂的简单药剂制度对于-0.5mm+0.1mm粒级物料,取得了SiO2品位>98.5%,回收率>93%的指标,对于-0.1mm+0.037mm粒级物料,取得了SiO2品位>99.3%,回收率>85%的指标,对于全粒级物料,在磨矿细度-0.044mm占85%的条件下,达到了SiO2品位>99.3%,回收率>75%的指标。以吉林某地原矿SiO2品位97.32%的石英矿为原料,通过棒磨擦洗-分级脱泥可除去大部分铁杂质,并在-0.074mm85%的磨矿细度下,以草酸做调整剂,十二胺做捕收剂,得到了SiO2品位>99.8%,回收率>85%的浮选精矿。以赤峰某地原矿SiO2品位97.45%的石英矿：在-0.044mm75%的磨矿细度下,以草酸做调整剂,十二胺做捕收剂,得到了SiO2品位>99.2%回收率>70%的浮选精矿。借助现代测试技术,首次发现了影响石英浮选精矿品位的原因是石英浮选精矿表面仍吸附有部分细粒级的长石颗粒。并利用石英纯矿物和细粒长石人工配制成石英浮选模拟精矿,进行了深度脱泥试验。以超声波与表面活性剂联合作用,消除了模拟精矿表面吸附的细粒长石,指导了实际石英矿的提纯。用上述开发的物理法提纯新工艺以及新开发的药剂制度对吉林、内蒙、辽宁三种不同产地的低品位石英矿进行了放大试验和深度脱泥试验,最大限度地提高了三种石英矿的品位。其中,吉林石英矿属于易选矿石,经过棒磨擦洗-磨矿-浮选-深度脱泥工艺,SiO2品位达到了99.9%以上,其他杂质含量也较低；辽宁朝阳石英矿嵌布粒度较细,经过磨矿-分级脱泥-浮选和深度脱泥工艺,SiO2品位达到了99.9%以上,其他杂质含量也较低；内蒙石英矿经过浮选和深度脱泥工艺,SiO2品位可达到了99.76%,仍有一部分杂质无法去除,推断有一部分微细粒长石包裹在石英颗粒内部,磨碎时没有充分解离,如果想进一步通过物理法提纯得到更高品位的SiO2存在较大的难度。对石英的浸出提纯进行了有益的探索,利用浓硫酸沸点高的特性,首次将浓硫酸常压高温酸浸引入石英提纯。取得了如下结果：常规浸出对-0.5mm+0.1mm粒级石英原矿的效果不理想,浸出精矿Al2O3品位在1%以上；对浮选精矿的常规浸出效果也不理想,最终优化条件试验得到SiO2品位在99.6%左右的石英精矿,Al2O3品位在0.3%左右；98.3%浓硫酸在沸点338℃以下对SiO2品位99.4%的石英浮选精矿中的杂质浸出有一定的效果,经过深度洗涤,可得到SiO2品位99.8%以上的石英砂产品。80%浓硫酸的强氧化性稍弱,对石英浮选精矿的浸出提纯也有一定的效果,也可得到SiO2品位99.8%以上的石英砂产品,可作为电子级石英砂产品。长石纯矿物的浸出试验表明,浓硫酸的常压高温酸浸不能完全将长石中的Al2O3完全浸出,其原因是长石颗粒表面的Al被浸出后,架状结构并没有被破坏,内部的Al并没有裸露出来,因此浸出不完全,但是经过浸出,降低了细粒级长石在石英表面的吸附能力,通过反复洗涤,可以最终提高石英精矿的品位。最后,借助于晶体化学理论、浮选溶液化学理论以及现代表面测试技术(X射线光电子能谱分析、傅立叶红外光谱分析及ζ电位测定等),对长石和石英矿物解离后的表面特性进行了系统的研究,认为长石的主要解离面是(010),经过计算其零电点为1.2,次解离面为(001)面,断裂面为(100)面。主解离面与其他两面表面特性有较大的差异,主解离面电负性强,与十二胺的作用也最强；长石与石英表面特性的不同是造成浮选过程中长石石英交互式影响的主要原因。长石的(010)面负电性最强,在pH2.5时,细粒级长石可以与石英发生静电作用力为主导的吸附作用,这样使石英表面出现了活化点,活化了石英的浮选,造成石英回收率的降低；草酸主要在长石的(001)和(100)面形成络合物,而与长石的(010)面作用不大,在加入草酸后,十二胺可以继续吸附在长石的(010)面,而使长石上浮；而草酸在石英整体表面的Si·正电区均可以发生吸附,形成络合物,阻止了十二胺的吸附。另外草酸的缓冲作用也使溶液pH值保持在石英的抑制范围,提高了石英的回收率。而超声波对粗细颗粒作用的差异是石英深度脱泥的主要原因,且表面活性剂的加入,使石英表面电负性更强,并且形成空间位阻作用,更有利于矿泥微细粒与石英颗粒的静电排斥作用。本研究的结果丰富了硅酸盐矿物浮选原理的理论体系,为其它复杂矿物浮选体系中矿物交互式作用的研究创立了新方法,对低品位石英矿的提纯具有一定的指导意义。更多还原

【Abstract】 Quartz is a kind of mineral resources with stably physical and chemical properties, used in very extensive fields. Ordinary quartz sand are used in glass, ceramics, rubber, foundry and other fields. The high purity quartz sand with SiO2 content more than 99.95%, is mainly used in high-tech industries such as aerospace, biotechnology, high-frequency technology, electronic technology, optical fiber communications, military and other fields. Only natural crystal (1,2 grade crystal) with limited reserves can meet their demands, additionally the rapid development of global semiconductor industry and optical fiber communication makes the resource trend to depletion. Therefore, it become the recent focus that to take use of various means to separation high purified quartz sand from common quartz sand.Quartz purification is an important flotation theoretical and practical task. Quartz often associates with other silicate minerals, mainly feldspars, both are silicate minerals with frame structure, and the surfaces of two minerals after dissociation have very similar characteristics, so the flotation separation of feldspar and quartz is difficult. Currently, the flotation researches of these two minerals are mainly focusing on cation/anion mixed collector to float feldspar from quartz under acidic condition and mixed acid leaching. To abtain high purity quartz, the selection of high grade ore for the purification is required, thus limiting the raw materials of high purity quartz. In order to abtain high purity quartz from ordinary quartz sand, systematic investigation is necessary.Firstly, the search for selectivity activator and inhibitor between feldspar and quartz was carried out through a large number of trials in laurylamine collector system by pure feldspar and quartz minerals flotation. Organic small molecule inhibitors were targeted and screened in laurylamine collector system. Oxalic acid, the high-selective inhibitor for the separation of feldspar and quartz, was found. Good indicators were both achieved under this new reagent system in flotation of artificial minerals and actual ore.It was first discovered that the interactive effects of fine fraction feldspar to feldspar and quartz separation. Rational reagent system was managed to decline the adverse impact caused by interactive function, and the flotation index was improved. Results of actual ore showed that: For the silica from Chaoyang with SiO2 grade 93% under the reagent system of oxalic acid as the regulator, dodecylamine as collector, the index of concentrates achieved: SiO2 grade>98.5% recovery rate>93.01% for the simple-0.5mm+0.1mm size fraction material, SiO2 grade>99.3% recovery rate>85% for-0.1mm+0.037mm size fraction material, SiO2 grade>99.3% recovery rate>75% for the full fraction material, at the grinding fineness-0.044mm 85%; For the silica from Jilin with SiO2 grade 97.32% under the reagent system of oxalic acid as the regulator, dodecylamine as collector, the index of concentrates achieved:SiO2 grade>99.8% recovery rate>85% at the grinding fineness-0.044mm 85%; For the silica from Chifeng with SiO2 grade 97.45% under the reagent system of oxalic acid as the regulator, dodecylamine as collector, the index of concentrates achieved:SiO2 grade>99.2% recovery rate>70% at the grinding fineness-0.044mm 75%.With the help of modern surface testing technology, it was first discovered that the ultimate impact factor on concentrate grade of silica flotation was due to the some fine feldspar adsorpted on the surface of quartz particles still. And the pure quartz minerals and fine feldspar minerals were used for simulating the flotation concentrates to carry out deeply deslime investigation. Ultrasonic treating combined surface active agent eliminated the adsorption of fine feldspar on the mimical quartz concentrate and this novel flow sheet can guide purification for the actual low-grade ore.Quartz ores from Jilin, Inner Mongolia, Liaoning three different origins were purified using the new reagent system and flow sheet. Jilin quartz ore was easy to purify, with the flow sheet of rod mill scrub-grinding-flotation-deep deslime, SiO2 grade of final concentrate reached 99.9%; Chaoyang quartz ore involved in finer dissemination, with the flow sheet of grinding-classification-flotation-deep deslime the SiO2 grade of final concentrate reached 99.9%; Inner Mogolia quartz ore, with the flow sheet of grinding-flotation-deep deslime, the SiO2 grade of final concentrate reached 99.76%. There maybe still a part of impurities can not be removed by this flow sheet, it could be infered that fine grained feldspar included in quartz particles not fully dissociated at this grinding fineness, it is more difficult to further a higher grade of SiO2.The leaching of quartz purification was explored making use of high boiling point properties of concentrated sulfuric acid. For the first time, high-temperature sulfuric acid leaching at atmospheric pressure was introduced into quartz purification, the following results were achieved: result of conventional leaching for-0.5mm+0.1 mm size fraction of quartz ore was not satisfactory, Al2O3 grade of ore leached was over 1%; the result of flotation concentrate leaching under conventional condition was also not satisfactory, the final concentrate with SiO2 grade 99.6%, Al2O3 grade 0.3%; the leaching experiment using 98.3% concentrated sulfuric acid under the boiling point of 338℃for quartz flotation concentrate with SiO2 grade 99.4% was carried out and SiO2 grade of 99.8% quartz sand products was obtained after deep washing, so was the 80% concentrated sulfuric acid leaching, and more than 99.8% SiO2 grade quartz products were obtained. Pure feldspar mineral leaching experiment showed that the atmospheric temperature sulfuric acid leaching can not leach completely Al2O3 from feldspar and the reason may be that after the Al on the surface of feldspar particles were leached, the internal Al did not turn out because of frame structure remained, Therefore, leaching was not complete, but the absorption ability of fine feldspar was destroyed during leaching. They can be ultimately wiped out from quartz particles by repeated washing.Finally, by means of crystal chemistry, flotation solution chemical theory and modern surface testing technology (X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy andξpotential measurement, etc.), surface characteristics of feldspar and quartz after dissociation was investigated thoroughly. The main dissociation surface of feldspar was (010), its zero-power point was calculated to be 1.2, the second dissociation surface surface was (001), and the fracture surface was (100). The surface characteristics of main dissociation surface are quite different from the other two surfaces. The main dissociation involved in strong electronegative and strongest function with dodecylamine; different surface properties of feldspar and quartz resulted in the interactive effects between feldspar and quartz flotation separation. (010) surface of feldspar charged strongest negative, at pH2.5, the fine feldspar and quartz can adsorb with each other by electrostatic force, so that the quartz surface turned out activation point, which activated the quartz flotation, resulting in reduced recovery of quartz; oxalic acid functioned mainly on (001) and (100) of feldspar forming complex and functioned very limitedly on (010) of feldspar, after added oxalic acid, dodecylamine can still adsorb on (010) surface of feldspar to float it; and oxalic acid can adsorb on all locations quartz surface forming complex, preventing the adsorption of dodecylamine. Another role of oxalic acid was to buffer solution pH value to maintain the inhibition range of quartz, which could improve the recovery rate of quartz. The different functions of ultrasonic between coarse and fine particles was the main reason for the deep deslime of quartz concentrate, moreover, the addition of surfactant made a more negative surface potential of quartz and formed steric effects, more conducive to electrostatic repulsion between micro-fine particles slime and quartz.The results of this investigation enriched the framework of flotation principles on silicate minerals, set up a series novle method on the research of interactive effect between complicated mineral flotation systems, and can guide the purification of low-grade quartz ore.更多还原