节点文献
个旧霞石正长岩综合利用的放射性研究
【作者】 李永佳；
【作者基本信息】 昆明理工大学 ， 有色冶金， 2013， 博士
【摘要】 个旧霞石正长岩是全国十余个同类矿物资源中含钾较高,又是我国地质工作程度最高、处理工艺研究最深的矿床,在首勘矿段内探获矿石储量5000余万吨,为工业化生产建设提供了充分的资源保证。若开发利用则可带动冶金、化工、建材等行业协同发展,形成滇南地区新的支柱产业,但是前期个旧霞石资源地质工作中保存下来的钻探岩心样,按新的放射性核素标准送检时,发现矿石除含有相当数量的放射性元素铀、钍之外,还含有较高的放射性同位素K40,且K40的放射性比活度高达3000Bq/Kg。为了明确个旧霞石矿处理过程中,各放射性核素比活度的强度和放射性核素在工艺处理过程中的走向与变化规律,论文采用国家《放射性废物的分类》标准,国家对长期接受放射性核素照射人员采用的人体接受放射性照射剂量标准,以及类比我国现有的稀土矿山及其加工厂的放射性评价标准,对个旧霞石正长岩矿床的放射性核素比活度及其对人体的危害进行了研究,同时进行了全流程工艺试验研究,重点研究的工序为：备料、烧成、溶出、脱硅、碳分、煅烧产出氧化铝。对进料样与出料样进行了放射性核素比活度鉴定,据检验结果确定各放射性核素在工艺处理过程中的行为与走向,论文的主要成果如下：(1)个旧霞石正长岩矿床中主要的放射性核素是210pb、238U、235U、232Th、2266Ra、40K和137Cs等七种,无论按矿石的总放射性强度、个别核素的放射性比活度、人体连续接触耐受的放射性计量标准来衡量,甚至按照国家对水泥规定的内、外照射指标来衡量,个旧霞石正长岩矿床都属于放射性较低的资源,不需要进行防护。(2)个旧霞石正长岩矿床放射性强度以及放射性比活度的分布规律,大体验证了前期据总伽马测量得出的结论,即在面上和沿纵深,绝大部分区域属于放射性强度的正常区,放射性核素与放射性强度的异常区,呈孤立的点状分布特征。(3)矿石加工处理过程中,各中间物料的放射性比活度和总放射性强度,都未达到放射性设防标准,亦即霞石烧结法整个工艺处理过程不须采取放射性防护措施,产品氧化铝的放射性比活度不高,属正常冶金产品,产品碳酸钠、碳酸钾,总α分别为2.75×103和3.33×104,均远远低于GB9133-1995低放射性废物总α=4×106的规定,属于不须防护的正常化工产品；产品水泥的内照指数IRa为0.69~0.75,外照指数Ir,为0.89~0.95,符合国家对建筑装饰材料规定的IRa≤1.0和I,≤1.0的标准,可以作为建筑的主体材料进行使用,使用范围不受限制,属正常水泥产品。(4)矿石加工处理过程中,放射性核素的走向各不相同,其中,最主要的放射性核素铀、钍、镭和钾的走向,决定着中间物料与最终产品的放射性强度变化规律：①铀,经烧成、溶出后,约一半略弱的留存在霞石泥中从而进入水泥系统,最终进入水泥产品中；约一半略强的进入溶液,溶液中的铀在脱硅、碳分处理时,大部留存在溶液中而进入制碱系统,制碱时,约3/4进入碳酸钾产品中,1/4进入碳酸钠产品中;②镭,经烧成、溶出后,约3/4的留存在霞石泥中从而进入水泥系统,最终进入水泥产品中；仅有约1/4进入溶液,溶液中的镭在脱硅、碳分处理时,大部留存在溶液中而进入制碱系统,制碱时,约3/4进入碳酸钾产品中,1/4进入碳酸钠产品中;③钍,经烧成、溶出后,约1/3的留存在霞石泥中从而进入水泥系统,最终进入水泥产品中；约2/3的进入溶液,溶液中的钍在脱硅、碳分处理时,大部留存在溶液中而进入制碱系统,制碱时,约3/4进入碳酸钾产品中,1/4进入碳酸钠产品中；④40K,经烧成、溶出后,近90%的溶入溶液,溶液中的40K在脱硅、碳分处理时,大部留存在溶液中而进入制碱系统,制碱时,约92%进入碳酸钾产品中,8%分散于碳酸钠产品中。论文的主要创新点为：对霞石正长岩矿床进行放射性研究,明确在矿石利用过程中可能产生的放射性影响,为霞石资源的开发提供依据。同时跟据放射性核素比活度测定结果,确定了各放射性核素在工艺处理过程中的行为与走向,明确矿石加工处理过程中,各中间物料(包括液体物料与固体物料)的主要放射性核素,并测定其比活度及总的放射性强度,对工艺流程中哪一些工序需要做放射性防护和做什么样级别的防护,给出了明确的结论,论文的完成为综合利用霞石正长岩资源提供了保证,有重要的现实意义和理论价值。
【Abstract】 Gejiu nepheline syenite is the kind of mineral resources in a dozen high potassium, but also the highest level of geological work in China, the deepest level of processing technology of deposits, mineral exploration in the first paragraph probe was5000million tons of ore reserves for industrial production and construction resources to provide a full guarantee. If exploitation can lead metallurgy, chemicals, building materials industry joint development, the formation of a new pillar industry in southern Yunnan region, but the early geological work in the old nepheline resources preserved drill core samples, according to a new standard for inspection of radioactive nuclides, we found that in addition to the ore contains a considerable amount of radioactive elements uranium, thorium, but also contains a high radioisotope K40, and K40of radioactivity up to3000Bq/Kg.In order to clarify Gejiu nepheline syenite processing, the intensity of radionuclide specific activity of radionuclides in the process and the process of direction and changes of use in this paper states " the classification of radioactive waste " standard, the state who receive long-term exposure to radionuclides in the human body to accept the use of the standard radiation dose, and the analogy of our existing radioactive rare earth mining and processing of evaluation criteria, the Gejiu nepheline syenite deposit, and the specific activity of radionuclides the study of health hazards, at the same time the whole process flow pilot study. Focus on the process of: preparation, firing, stripping, removal of silicon, carbon points, calcined alumina output. Sample of the feed material samples with a specific activity of radioactive nuclide identification, according to test results to determine the radionuclide in the process of the processing behavior and direction, the conclusion is as follows:(1) Gejiu nepheline syenite deposits are the main radionuclides210Pb,238U,235U,232Th,226Ra,40K and137Cs seven kinds, regardless of the total radioactivity by the ore, the radioactivity of the individual radionuclide, tolerance of human exposure to radioactive continuous measurement standards, and even cement in accordance with the provisions of the state’s internal and external exposure indicators to measure, old nepheline syenite deposits belong to the low radioactivity of resources, do not need protection;(2) Gejiu nepheline syenite deposits of radioactive intensity and distribution of radioactivity, according to generally verify the pre-measured total gamma conclusion that, in the surface and along the depth, most regions are radioactive intensity of the normal zone, radionuclides and radioactive intensity anomalies, was isolated point-like distribution;(3) Ore processing process, the intermediate material and the total radioactivity radioactivity, failed to meet minimum security standards for radioactivity, which nepheline sintering process is not the whole process of radioactive protective measures to be taken, the product of alumina radioactivity is not high, normal metallurgical products, sodium carbonate, potassium carbonate, total a were2.75×103and3.33×104, are far below the GB9133-1995low-level radioactive waste total a=4×106requirements requirements, are not normal to be protective chemical products; Products within the cement according to index I Ra of0.69to0.75, according to index I y outside the0.89to0.95, in line with national requirements for building and furnishing materials I Ra≤1.0and I γ≤1.0standard, can be used as the main material for building use, use of unrestricted. Normal cement products;(4) Ore processing process, the radionuclides to vary, in which the most important radionuclides of uranium, thorium, radium and potassium to determine the intermediate and final products of radioactive material intensity variation:①uranium, after firing, dissolution, about half of the slightly weaker retained in nepheline mud to enter the cement system and eventually into the cement product; about half of the slightly stronger into the solution, the solution of uranium in the de-silicon and carbon sub-processing, retained most of alkali in the solution and into the system, soda, about3/4into the potash products,1/4into the sodium carbonate products;②radium, after firing, dissolution, about3/4retained in nepheline mud to enter the cement system and eventually into the cement product; only about1/4into the solution, the solution of radium in the removal of silicon, carbon sub-processing, but most retained in solution into the alkali systems, soda, about3/4into the potash products,1/4into the sodium carbonate products;③thorium, after firing, dissolution, about1/3of remaining in nepheline mud to enter the cement system and eventually into the cement product; about2/3into the solution, the solution of thorium in the removal of silicon, carbon sub-processing, retained most of alkali in the solution and into the system, soda, about3/4into the potash products,1/4into the sodium carbonate products;④40K, after firing, dissolution, nearly90%of the dissolved solution, the solution of40K in the de-silicon, carbon sub-processing, but most retained in solution into the alkali systems, alkali, about92%into the potash products,8%dispersed in sodium carbonate product.Main innovation of this paper are:deposits of nepheline syenite for radiationresearch, specifically in the ore that may arise during the use of radioactive impact, as nepheline provide the basis for resource development. According to both the specific activity of radionuclides measured results to determine the radionuclide in the process of dealing with the behavior of the process and direction, a clear process of ore processing, the intermediate materials (including liquid material and solid material), the main radionuclides factors, and determine its specific activity and total radioactivity of the process in which some of the processes needs to be done and what kind of radiation protection level of protection, given the clear conclusion,this paper to complete utilization of nepheline syenite for the resources to provide a guarantee.