(中南大學(xué) 冶金與環(huán)境學(xué)院，長沙 410083)
摘 要: 輝鉬礦經(jīng)氧化焙燒轉(zhuǎn)化成MoO3的過程中，伴生的銅鉛鐵等硫化礦亦被氧化，并與MoO3生成難溶鉬酸鹽。為減少因難溶鉬酸鹽帶來的鉬損失，需要對這些鉬酸鹽進行再浸出處理。針對這些鉬酸鹽濕法浸出過程進行熱力學(xué)分析，繪制了25 ℃時Me-Mo-H2O(Me：Cu，Pb，F(xiàn)e)系組分的濃度對數(shù)-pH圖。利用熱力學(xué)平衡圖對氫氧化鈉分解鉬酸鹽進行熱力學(xué)分析。結(jié)果表明：整個pH值范圍可分為H2MoO4的穩(wěn)定區(qū)、難溶鉬酸鹽的穩(wěn)定區(qū)、Me(OH)n的穩(wěn)定區(qū)。高pH區(qū)鉬酸鹽中的Me轉(zhuǎn)變?yōu)榉�(wěn)定的Me(OH)n物相，即實現(xiàn)了鉬酸鹽的堿分解。而Fe2(MoO4)3、CuMoO4和PbMoO4的堿浸出難度依次遞增，達到一定堿度時這3種難溶鹽都能很好地分解，并實現(xiàn)Me與Mo的分離。但過高的堿度又使大量的金屬以羥基配合物離子的形式進入溶液，增加了后續(xù)除雜難度。
關(guān)鍵字: 鉬酸高鐵；鉬酸銅；熱力學(xué)；氫氧化鈉；浸出
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:When molybdnite was roasted, MoS2 converts to MoO3. Meanwhile, sulfides associated with concentrate are oxidized to copper oxide and lead oxide and iron oxide or partial copper sulfate and lead sulfate and iron sulfate, which will react with MoO3 to form sparingly soluble molybdate. Aiming to decrease the loss of molybdenum in the slag, these sparingly soluble salts have to be handled with. According to the laws of conservation of mass and simultaneous equilibria, the logarithm concentration-pH diagram of Me-Mo-H2O (Me: Cu, Pb, Fe) system was established on the basis of thermodynamic data at 25 ℃. Thermodynamic analysis was carried out to discuss the technology of sodium hydroxide disintegrating sparingly soluble molybdate. The results show that the whole pH value of the system is divided into three areas. The first one is the stable area of H2MoO4, the second area is the stable area of sparingly soluble molybdate, the third one is the stable area of Me(OH)n. In the third area, Me(OH)n is gradually supersaturated in solution with the increase of pH value, so the Me(OH)n is deposited as sediment, and MoO42- goes into solution. As a result, the processing of sparingly soluble molybdate leached by sodium hydroxide is carried out. The incremental difficulty of alkali leaching order is as follows: Fe2(MoO4)3, CuMoO4, PbMoO4. Over a certain alkalinity, copper, lead and iron could be leached out of molybdenum. But these metals will be dissolved numerously as hydroxyl complexes in the case of excessive basicity, which increases the difficulty of subsequent purification.
Key words: ferrimolybdate; copper molybdate; thermodynamics; sodium hydroxide; leaching
