湖南省建筑用水泥的辐射安全评价

目的 对水泥中的镭、钍、钾、天然放射性含量进行分析。方法 依据国家相关标准。结果 建筑物内的辐射剂量率为0.42×10^-8 Gy·h^-1。结论 湖南省生产的水泥放射性含量未超过国家标准限值,使用不受限制。     

居室环境放射性现状评价

目的 为了掌握居室环境放射性水平,并对当前室内环境的放射性水平做出评价。方法 使用自制的"室内环境放射性评价测量盒"(专利号:ZL200620082698.7)对室内环境中²²²Rn活度浓度、²²⁰Rn活度浓度、²²⁰Rn子体的平衡当量浓度(EEC_Tn)以及γ外照射剂量率进行测量。结果 测量济南市室内²²²Rn共411间次,活度浓度范围为18~203Bq·m^-3,呈对数正态分布,几何均值为45Bq·m^-3;测量室内²²⁰Rn共203间次,其活度浓度范围为1~167Bq·m^-3,几何均值为16Bq·m^-3;测量室内²²⁰Rn子体的平衡当量浓度共204间次,其活度浓度范围为0.015~10.230Bq·m^-3,几何均值为1.082Bq·m^-3;测量室内γ外照射剂量率共412间次,其γ外照射剂量率范围为0.041~0.167μSv·h^-1,呈正态分布,算术均值为0.106μSv·h^-1。结论 居民由²²²Rn及其子体造成的内照射剂量为1.189mSv/a;由²²⁰Rn及其子体造成的内照射剂量为0.255mSv/a;由γ外照射外照射剂量为0.743mSv/a;年均总剂量为2.187mSv,最大年均剂量已超过5mSv。     

某扩容γ辐照加工装置辐射安全分析与评价

目的 评价某γ辐照加工装置扩容后的辐射防护效果及运行安全性,保障环境辐射安全。方法 通过测量辐照装置工作场所及周围环境瞬时γ辐射剂量率、外照射累积剂量、贮源井水放射性核素含量、工作人员个人剂量等放射性指标,统计分析及核查运行系统故障率及安全保障系统的有效性等运行指标,评价该γ辐照加工装置扩容后运行的辐射防护效果和运行安全效果。结果 结果表明,扩容后辐照装置工作场所及周围环境瞬时γ辐射剂量率为0.042~0.55 μGy·h^-1,γ外照射年累积剂量水平在0.07~0.97 mSv之间,贮源井水中⁶⁰Co活度浓度未检出,工作人员年个人有效剂量在0.079~1.58 mSv·a^-1,工艺系统运行故障率保持在0.5%~1.0%的水平,所有安全保障设施正常有效。结论 该设施扩容后辐射屏蔽设施防护水平可以满足国家相关标准要求,公众人员和辐射工作人员年有效剂量满足低于1mSv·a^-1和20 mSv·a^-1的限值要求。     

某稀土企业环境放射性水平调查

目的 调查和掌握某稀土企业环境放射性水平,为放射性污染防治提供对策。方法 对稀土厂环境γ外照射剂量率、土壤放射性核素比活度、地下水总α、总β比活度进行检测。结果 部分工作场所环境γ外照射明显高于环境本底水平,土壤天然放射性核素比活度略高于江苏省平均值,地下水总α、总β比活度无明显变化。结论 加强对稀土生产企业的管理,降低环境放射性水平。     

湛江市建筑材料放射性水平调查

目的 调查湛江市6类建材成品的放射性水平。方法 按照国家标准GB6566-86。结果 γ辐射水平的均值为11.79×10^-8 Gy·h^-1,天然放射性核素比活度均值为:²²⁶Ra:53.32 Bq·kg^-1、²³²Th:46.13 Bq·kg^-1、⁴⁰K:613.81 Bq·kg^-1。结论 我市建材成品均属正常天然辐射范围。     

武汉地区核医学放射防护现状及存在问题探讨

目的 调查了解武汉地区核医学放射防护现状,探讨解决和改进放射防护中存在问题的方法和措施。方法 采用事前不通知的方式突击监督检查,调查实验基本采用现场监测仪器直接读数法。结果 1.临床核医学医疗照射主要用于甲状腺的检查和治疗,核医学医疗照射的年频率有逐年增长的趋势。核医学工作单位比较规范,工作人员基本持有《放射工作人员证》,但实习学生未办证情况较为普遍。2.非密封型工作场所及操作人员操作时的γ外照射水平及β表面污染情况以淋洗环节最高,γ外照射水平最高达28μGy·h^-1,均值为24μGy·h^-1;β表面污染最高达296.62 Bq·cm-2,均值为40.51 Bq·cm-2。3.核医学放射工作人员2003-2004年个人剂量监测结果表明分装操作人员0.31~14.60 mSv·a^-1;护士为1.70~14.20 mSv·a^-1;测量人员0.12~3.31 mSv·a^-1;医师0.02~0.83 mSv·a^-1。4.70%的核医学工作单位通风柜达到防护要求。5.46.67%的单位有专门核医学废物库,多数单位是在实验室内存放或暂存废物。废物堆表面γ照射剂量率最高为55.00 μGy·h^-1,平均值为10.16 μGy·h^-1。结论:武汉地区核医学放射防护情况总的较好,但对注射了核素的患者管理和放射性废物的防护与管理工作有待加强。     

海南部分地区土壤样品中放射性水平调查

目的 对海南部分地区土壤样品中的放射性水平进行评估。方法 在2012年期间,为了评估土壤中放射性,在中国海南省收集表层土壤样品。用低本底高纯锗γ谱仪测量了15个土壤样品中的放射性。结果 样品中²²⁶Ra、²³²Th和⁴⁰K的平均放射性浓度分别为(26.3±1.0),(23.7±0.90)和(366.1±13.4) Bq·kg^-1。而¹³⁷Cs的活度浓度变化范围值< 0.35 Bq·kg^-1(最小可探测活度浓度)到2.25 Bq·kg^-1。通过使用土壤样品中²²⁶Ra、²³²Th和⁴⁰K的数据结果推算户外空气中γ剂量率值为(41.7±1.5) nGy·h^-1。土壤中放射性核素所致居民人均外照射年有效剂量为0.05 mSv。结论 土壤样品分析结果表明,所有调查点的测量结果属正常环境水平,未见异常。     

DMC 450同位素测厚系统放射卫生防护评价

目的 调查对工作场所及环境的影响,进行放射卫生防护安全性评价,提高放射防护水平,保护工作人员及公众健康。方法 在DMC同位素测厚仪所能影响的范围内布点测量,在测厚仪放射源正常工作状态下,3 d内测量3次,取其平均值其结果扣除放射性本底,工作状态时车间内辐射水平为0.015~5.15 μSv·h^-1。结果 非工作状态时,源箱外辐射水平5 cm处平均为1.28 μSv·h^-1,100 cm处平均为0.29 μSv·h^-1。结论 该DMC 450同位素钢板测厚仪使用时对工作场所及环境的放射卫生防护符合GB 16354-1996要求。     

新疆大学校园辐射环境水平调查

目的 调查新疆大学校园辐射环境水平。方法 以新疆大学校园辐射环境水平为研究对象,初步调查校园环境外照射辐射剂量、氡气浓度以及土壤和水体中的天然放射性核素浓度。结果 校园内环境γ吸收剂量率范围为71.9~90.8nGg/h,氡气浓度13~29Bq/m³,土壤和水体中的天然放射性核素浓度也均在当地本底范围内。结论 新疆大学校园内辐射环境水平处于新疆本底值范围内,未见异常。     

福清核电站运行前环境γ辐射水平及所致居民剂量估算

目的 调查福清核电站运行前环境地表γ辐射剂量率及其所致居民暴露剂量。方法 按照《环境地表γ辐射剂量率测定规范》(GB/T 14583-1993)和《辐射环境监测技术规范》(HJ/T 61-2001)的要求,用GPS全球定位器确定监测点位置,选择17个监测点作为调查区,用Radalert 100 Nuclear放射性检测仪测量环境γ辐射空气吸收剂量率,估算居民暴露剂量。结果 核电站周围17个监测点的环境地表γ辐射空气吸收剂量率居室内变化范围为96~238nGy/h,平均值为191 nGy/h,居室外变化范围为73~177 nGy/h,平均值为144 nGy/h,由环境辐射外照射致福清市居民人均年有效剂量为1113.6 μSv,集体年有效剂量为1375.1 man·Sv。结论 福清核电站周围地表γ辐射空气吸收剂量率水平属于福建省正常环境放射性本底水平。     

Research on Bayer Red Mud Slurry Electrolysis

Bulletin of Environmental Contamination and Toxicology - The Bayer red mud is the solid waste generated during the production of alumina by the Bayer process. At present, the stock of red mud in...     

Applications of Red Mud as a Masonry Material: A Review

Red mud (RM) is a highly alkaline by-product produced by the aluminium industry. The total stockpile of RM in the world is evaluated to be close 4 billion tons, which caused serious soil and water pollution. The use of RM in masonry materials has proven to be a prospective strategy to alleviate the environmental problems caused by RM. During the past decades, various economical treatment methods have been developed for utilization of RM as a masonry material. There are two general categories of products using RM in masonry materials: sintered products and non-sintered products. In this review, the physicochemical properties of RM are introduced, and the different application scenarios for RM in masonry materials are summarized, which is valuable for solving the environmental problems caused by the accumulation of bauxite residue. Moreover, the potential environmental risks of utilizing RM are described. Finally, suggestions for solving the RM problem are proposed.

     

Calcification-Carbonation Method for Bayer Red Mud Treatment: Carbonation Performance of Hydrogarnets

Bulletin of Environmental Contamination and Toxicology - Hydrogarnets are vital intermediate products in the calcification- carbonation method, which is designed for Bayer red mud treatment. Their...     

Transformation Behavior of Iron Minerals in High-Iron Red Mud During High-Pressure Hydrothermal Reduction

Nowadays, the comprehensive utilization of red mud is still a difficult problem. Using starch as the reducing agent, the "high-pressure hydrothermal reduction method" is used to separate and recover sodium, aluminum, and iron in high-iron red mud in one step in an alkaline hydrothermal system. This article focuses on the hydrothermal reduction behavior of the iron ore phase. The results showed that starch formed a strong reduction system through degradation under alkaline hydrothermal conditions, in which Fe₂O₃ was first partially dissolved and reduced to form Fe[OH]⁺, then Fe[OH]⁺ further reacted with Fe₂O₃ to form Fe₃O₄. At a temperature of 260°C, a C/S (calcium to silicon ratio) of 3.5, a Na₂O concentration of 250 g/L, W_{high-iron red mud}/W_starch?=?10, the Fe reduction rate was 98.46%, and the transformation slag at a magnetic field strength of 1800 Gs resulted in a magnetic iron concentrate powder with a TFe grade of 65.75%.

     

Study on Preparation and Properties of Red Mud Magnesium Oxysulfate Cement Foamed Concrete

Bulletin of Environmental Contamination and Toxicology -     

Experimental Research on Vortex Melting Reduction of High-Iron Red Mud (Bauxite Residue)

Bulletin of Environmental Contamination and Toxicology - In this study, the advantages of the vortex melting reduction treatment of red mud were verified. Vortex melting reduction can improve the...     

Phase Transformation Behavior of the Aluminosilicate Phase During High-Pressure Hydrothermal Reduction of High-Iron Red Mud

One-step separation and recovery of sodium, aluminum and iron in high-iron red mud in a high-calcium alkaline hydrothermal system is realized by a high-pressure hydrothermal reduction process. The transformation behavior of the aluminasilica phase in high-iron red mud is mainly investigated. The results show that under the optimized conditions, a temperature of 290℃, a Na₂O concentration of 240 g/L, a calcium to silicon ratio of 3.5, and a liquid–solid ratio of 5, the Na₂O content in the transition slag is reduced to 0.12%, the dealkalization rate can reach 98%, and the alumina dissolution rate is 73%. When the starch-free reductant is added, the transition slag mainly consists of hematite and hydroandradite, and when the starch reductant is added (the addition amount is 1/4 that of ω(Fe₂O₃) in the red mud), all Fe₂O₃ in the transition slag is completely reduced to Fe₃O₄, and the main phases are magnetite and hydrogrossular.

     

Mortar Designed from Red Mud with Iron Tailings and Moulded by 3D Printing

A specific mortar material (abbreviated as RFT) was designed from industrial solid wastes, such as red mud, fly ash, and iron tailings. It was mainly developed for 3D printing in this work. Mechanical properties, microstructure and heavy metal leaching properties were discussed. The RFT composed of 15% red mud, 45% iron tailings, 9% fly ash, 30% cement, and 1% FDN water reducing agent attained good mechanical properties. Hydration products including Ca(OH)₂, ettringite and C-S-H gel were found in RFT through SEM observation. Iron tailings mainly acted as fine aggregates in RFT, and they were wrapped by the C-S-H gels, producing a strong bonding effect between aggregates and cementitious matrix. The leaching toxicity test results proved that the developed RFT mortar materials were environmentally acceptable. Finally, RFT was subjected to a 3D printing test to verify its feasibility as 3D printable construction material.

     

Preparation and Characterization of Red Mud/Fly Ash Composite Material (RFCM) for Phosphate Removal

Bulletin of Environmental Contamination and Toxicology - In this study, a new red mud/fly ash composite material (RFCM) for phosphate removal was prepared by granulation and activation methods,...     

Performance of Red Mud/Biochar Composite Material (RMBC) as Heavy Metal Passivator in Pb-Contaminated Soil

Bulletin of Environmental Contamination and Toxicology - Red mud/biochar composite material (RMBC), which was applied as heavy metal passivator in this research, was prepared with red mud (the...