(1. 中南大學(xué) 資源與安全工程學(xué)院，長(zhǎng)沙 410083;
2. 南華大學(xué) 鈾礦冶生物技術(shù)國(guó)防重點(diǎn)學(xué)科實(shí)驗(yàn)室，衡陽 421001)
摘 要: 堆浸鈾尾渣中鈾含量普遍高于0.02%，為了降低鈾尾渣中的鈾含量，采用頻率為2450 MHz工業(yè)微波對(duì)鈾尾渣進(jìn)行了預(yù)處理，考察微波功率、輻照時(shí)間和尾渣質(zhì)量對(duì)鈾尾渣浸出行為的影響，探討微波預(yù)處理提高鈾尾渣中鈾的浸出率的機(jī)理。結(jié)果表明:微波預(yù)處理的最佳條件為2.5 kg鈾尾渣在50 kW功率下輻照30 s，此時(shí)鈾浸出率達(dá)到80.12%，相比未經(jīng)預(yù)處理時(shí)的鈾浸出率75.63%提高了4.49%。一定條件下的微波輻照促使鈾尾渣中鈾的價(jià)態(tài)和賦存形態(tài)向有利于浸出的方向轉(zhuǎn)化，經(jīng)30 kW功率微波輻照30 s后，相比對(duì)照組尾渣中U(Ⅳ)比例下降了17.78%；經(jīng)20 kW功率微波輻照30 s后, 相比對(duì)照組尾渣中弱酸提取態(tài)鈾比例提高了15.55%。MLA分析表明，經(jīng)微波預(yù)處理的尾渣中單體顆粒明顯增加，鈾的單體解離度提高有利于浸出。
關(guān)鍵字: 堆浸鈾尾渣；微波預(yù)處理；礦物解離；價(jià)態(tài)；賦存形態(tài)
（1.School of Resources and Safety Engineering, Central South University, Changsha, 410083, China;
2. Key Discipline Laboratory for National Defence for Biotechnology in Uranium Mining and
Hydrometallurgy, University of South China, Hengyang 421001, China）
Abstract:Heap-leached uranium tailings usually contain uranium more than 0.02%. In order to lower the content of uranium, the uranium tailings were pretreated by 2450 MHz industrial microwave. The factors, including microwave power, irradiation time and tailings mass, which influence on the leaching behavior of uranium tailings, were investigated, and the mechanism of microwave pretreatment on improving extraction of uranium from uranium tailings was discussed. The results show that the optimal pretreatment condition are the microwave power of 50 kW, the irradiation time of 30 s, the tailings mass of 2.5 kg. And under this condition, the leaching rate of uranium increases to 80.12%, which is 4.49% higher than that of the control group(75.63%) under the condition without microwave pretreatment. Under a certain condition, the microwave pretreatment can help uranium valence state and occurrence form to beneficially transform to leaching. After irradiating for 30 s at 30 kW, the total amount of U(Ⅳ) decreases by 17.78% compared with that of the control group, while after irradiating for 20 s at 30 kW, the total amount of weak acid soluble uranium increases by 15.55% compared with the control group. The MLA analysis shows that the mono mineral particle of uranium significantly increases after microwave pretreatment, hence the increase of uranium mineral liberation is beneficial to leaching.
Key words: heap-leached uranium tailings; microwave pretreatment; mineral liberation; valence; occurrence form
