摘要：我国的稀土工业经历了过去三十多年的飞速发展，如今已成为目前世界上最大的稀土生产国、稀土消费国以及稀土出口国。由于稀土资源伴生着大量放射性核素，所以在对稀土资源的开发利用中，对环境和人类可能造成放射性危害。我国目前的稀土冶炼工艺，放射性核素主要集中在其废渣中。对于工艺产生的大量的各种稀土废渣，我国稀土行业急需妥善的处理、处置方法与管理制度。64559

由于酸碱性能影响稀土酸溶渣的浸出液，本文拟通过加入氢氧化钠、氧化钙等碱性物质来探究此法是否能降低酸溶渣浸出液的比活度。按比例配置各组分所需样品，模拟水浸出实验，探究各组分在不同条件下浸出液含渣量的变化规律；对比加入同种碱性物质的样本，探究其浸出液比活度随时间的变化规律；控制酸碱性一样,探究加入不同碱性物质的组分的浸出液的比活度变化差异。

实验结果表明在稀土酸溶渣中加入氢氧化钠与氧化钙都能有效降低其浸出液比活度，加入氧化钙的效果明显好于加入氢氧化钠的效果，并且由于氢氧化钠易随着浸出液排除,所以从效果上、经济上、资源的利用上、控制二次污染上综合考虑，氧化钙比氢氧化钠更适合用来处理稀土酸溶渣。而用氧化钙处理稀土酸溶渣时，仅混合少量氧化钙，就能做到长时间降低浸出液比活度，不但效果好，资源利用率高，更能减少对环境的二次污染。

毕业论文关键字：稀土工业 稀土渣 处理与处置 混合碱 氢氧化钠 氧化钙

Preliminary exploration of the treatment and disposal of low-level radioactive rare earth acid dross

Abstract: China has become the largest producer, consumer and exporter of rare earth due to the rapid development of rare earth industry in the recent 30 years. Since rare earth resources emit enormous radioactive nuclides, the exploitation and utilization of rare earth resources pose potential radiological hazards to the ecological system and human health. In China’s rare earth processing plants, radioactive nuclides are mainly transferred to waste residues for disposal. In order to properly dispose these radioactive rare earth residues, it is crucial to employ appropriate treatments, disposal methods and regulations. 

Since pH influences the specific activity of the rare earth acid dross extract, this experiment was to test if the addition of NaOH and CaO2 would lower the specific activity of the extract. The amount of rare earth residues extracted at varies controlled conditions of the prepared solutions was investigated. When the same alkaline sample, either sodium hydroxide or calcium peroxide was controlled, an experiment testing the change in specific activity of the extract versus time was conducted. When controlling pH, the change in specific activity of the extract versus the addition of different alkalis was conducted.

According to the results obtained, the addition of both sodium hydroxide and calcium peroxide were capable of lowering the specific activity of the extract. However, since sodium hydroxide might be leaked out along with the exact, sodium hydroxide is not a wise choice in terms of effectiveness, running cost, utilization of resources, and prevention of secondary pollution. On the other hand, calcium peroxide is the optimal chemical that should be used to treat rare earth acid dross for effective and safe continuous use.

Key words: Rare earth industry, rare earth residues, treatment and disposal, mixed alkalis, calcium peroxide.

目录

1  绪论 1

1.1 我国稀土工业的概况 5

1.1.1 什么是稀土元素 6

1.1.2 我国稀土矿的分布及类型