本文選題：高鉍鉛陽(yáng)極泥　切入點(diǎn)：焙燒預(yù)氧化　出處：《昆明理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：高鉍鉛陽(yáng)極泥是粗鉛電解精煉過程中在陽(yáng)極區(qū)產(chǎn)生的一種副產(chǎn)品,含鉍、砷、銻、鉛、錫及貴金屬等多種元素,也是回收金屬鉍的重要原料。由于砷及其化合物具有揮發(fā)性,采用傳統(tǒng)的火法工藝處理鉛陽(yáng)極泥時(shí)容易產(chǎn)生含砷煙塵給環(huán)境帶來(lái)砷害,濕法處理工藝流程長(zhǎng),容易造成砷的分散及二次污染。銻與鉍的電極電位接近,采用電解法進(jìn)行鉍的提取時(shí),陰極上會(huì)出現(xiàn)銻和鉍的共析,給陰極鉍的質(zhì)量帶來(lái)影響。本文針對(duì)高鉍鉛陽(yáng)極泥砷銻含量高的特點(diǎn),提出了“焙燒預(yù)氧化—堿性浸出脫砷”和“加壓氧化堿性浸出脫砷銻”工藝來(lái)處理高鉍鉛陽(yáng)極泥,為后續(xù)金屬鉍及有價(jià)金屬的富集與提取奠定基礎(chǔ)。本研究所用的原料是鉍含量45%、Bi/As為4.9、Bi/Sb為4.3的鉛陽(yáng)極泥。首先進(jìn)行了鉛陽(yáng)極泥脫砷方案的實(shí)驗(yàn)初探,包括常壓水溶液氧化浸出和預(yù)氧化—堿性水溶液浸出,分別對(duì)氧化劑的種類、浸出劑及預(yù)氧化方式對(duì)脫砷效果的影響進(jìn)行了實(shí)驗(yàn)探索,確定了以亞硝酸鈉作氧化劑,采用焙燒預(yù)氧化—堿性浸出工藝進(jìn)行鉛陽(yáng)極泥脫砷處理的技術(shù)路線。詳細(xì)考察了焙燒預(yù)氧化—堿性浸出過程中焙燒溫度、液固比、碳酸鈉用量、氧化劑用量及氫氧化鈉濃度對(duì)脫砷率的影響,獲得了較佳工藝條件：焙燒溫度400℃,焙燒時(shí)間2h、液固比5：1,碳酸鈉用量為鉛陽(yáng)極泥質(zhì)量的40%、氧化劑(NaNO2)用量為鉛陽(yáng)極泥質(zhì)量的15%,氫氧化鈉濃度120g/L,堿浸溫度80℃,堿浸時(shí)間1h,該工藝條件下,砷的浸出率達(dá)到了95%以上,脫砷效果較好,但銻的浸出率僅在4%左右,因此還需進(jìn)行脫銻研究。采用加壓氧化堿性浸出工藝對(duì)鉛陽(yáng)極泥進(jìn)行了一步法脫除砷銻的實(shí)驗(yàn)研究,確定了以硝酸鈉作氧化劑,氫氧化鈉體系加壓氧化浸出處理鉛陽(yáng)極泥的技術(shù)方案。對(duì)實(shí)驗(yàn)中影響脫砷銻的各因素,如氧化劑用量、氫氧化鈉濃度、液固比、浸出溫度及反應(yīng)時(shí)間進(jìn)行了詳細(xì)考察,獲得了較佳的工藝條件：氧化劑用量為鉛陽(yáng)極泥質(zhì)量的15%、NaOH濃度150g/L、液固比7：1、浸出溫度180℃、反應(yīng)時(shí)間2h,該工藝條件下,砷、銻的浸出率分別達(dá)到了95.16%和80.51%,浸出渣中Bi/As、Bi/Sb分別達(dá)到了72和25,金銀含量也由原來(lái)的24.30g/t、3408g/t富集到了38.20g/t和5878g/t,達(dá)到了預(yù)期的效果。分別采用靜置冷卻沉砷及向沉砷后液中加雙氧水沉銻的方法進(jìn)行堿浸液的凈化處理,砷、銻、鉛分別以砷酸鈉、焦銻酸鈉和銻酸鉛的形式予以回收,凈化后液經(jīng)補(bǔ)加定量的氫氧化鈉能夠返回浸出工序。在小實(shí)驗(yàn)的基礎(chǔ)上,進(jìn)行了公斤級(jí)實(shí)驗(yàn),實(shí)驗(yàn)重復(fù)性好,渣率、金屬浸出率、堿浸液凈化效果及循環(huán)利用率穩(wěn)定可靠。
[Abstract]:High bismuth lead anode slime is a by-product produced in the anode region in the process of coarse lead electrorefining. It contains many elements, such as bismuth, arsenic, antimony, lead, tin and precious metal, and is also an important raw material for recovering metal bismuth. It is easy to produce arsenic-containing dust in the treatment of lead anode slime by traditional pyrotechnics. The wet treatment process is long, and it is easy to cause arsenic dispersion and secondary pollution. The electrode potential of antimony and bismuth is close to that of bismuth. When bismuth is extracted by electrolysis, antimony and bismuth eutectoid will appear on the cathode, which will affect the quality of bismuth cathode. The processes of "calcination preoxidation-alkaline leaching for arsenic removal" and "pressure-oxidized alkaline leaching for arsenic and antimony removal" were proposed to treat high bismuth lead anode slime. In this study, the raw material used in this study is the lead anode slime with bismuth content of 45% and Bi / as = 4.9% SB = 4.3. First, the experiment of arsenic removal from lead anode slime was carried out. Including atmospheric pressure aqueous solution oxidation leaching and preoxidation alkaline aqueous solution leaching, the effects of oxidizing agent, leaching agent and pre-oxidation method on arsenic removal efficiency were investigated respectively. Sodium nitrite was used as oxidant, and sodium nitrite was used as oxidant. The technological route of removing arsenic from lead anode slime by roasting preoxidation and alkaline leaching process was introduced. The calcination temperature, the ratio of liquid to solid, the amount of sodium carbonate in the process of roasting preoxidation and alkaline leaching were investigated in detail. The effect of the amount of oxidant and the concentration of sodium hydroxide on the arsenic removal rate was studied. The optimum technological conditions were obtained as follows: calcination temperature 400 鈩，

本文編號(hào)：1561682