金回收: 使用TULSION® 杜笙離子交換樹脂從氰化物溶液中回收金.
Gold Recovery : From cyanide liquor USING TULSION® ION EXCHANGE RESIN.
簡介/ INTRODUCTION :
傳統(tǒng)上使用活性碳吸附金子。珍貴的金會被活性碳吸附于表面,再藉由洗滌或直接焚燒以回收金。
Conventionally activated carbon is used for extracting the gold from the mother liquor commonly contacted with beds of activated-carbon. The precious noble metal loaded on the activated carbon is recovered by elution or simply by incineration of the carrier at high temperature.
使用離子交換樹脂回收貴金屬比活性碳還具有多方面的優(yōu)勢, 因為藉由特殊制造過程中, 我們可以在其結(jié)構(gòu)上的有效官能基上置入具有選擇性的離子,以選擇性的吸附此貴重金屬。
Ion exchange resins are more versatile substrates than activated carbons can be used, because specific functional groups can be afixed on the resin matrix, for better selectivity, during the synthesis. These resin can be tailor-made to improve the gold carrier features such as selectivity, resistance to poisoning by calcium or organic materials and loading capacity.
因此, 由于具有經(jīng)濟考慮優(yōu)勢, 離子交換樹脂普遍被使用于貴金屬回收。而大部份使用陰離子交換樹脂來交換吸附貴金屬。
Therefore the ion exchange resins are economically adopted for the gold recovery. Mostly Anionic type of ion exchange resin are used that adsorb the gold.
用氰化物萃取金的過程中, 金會以陰離子的氰化金型式存在, 既Au(CN)2- ; 再經(jīng)由強堿或弱堿的陰離子交換樹脂交換回收。如Tulsion®A-23（強堿）,Tulsion®A-27mp（強堿）及Tulsion®A-2X mp (弱堿) 。
The gold extracted by cyanidation is in the form of anionic aurocyanide complex Au(CN)2 - and can be recovered from the pregnant solution by ionic exchange with strong or weak base anion exchange resin ,such as Tulsion®A-23,Tulsion® A-27MP and Tulsion®A-2XMP
(a) 強堿離子交換樹脂方面的應(yīng)用:
此型的強堿型陰離子樹脂具有四級銨的官能基,在高pH 值的溶液中,藉由交換氯離子的相反離子來吸附Au(CN)2
- ; 其反應(yīng)機構(gòu)如下:
(a) STRONG BASE ANION:
These resins contain quaternary ammonium functionality which, when contacted with the high pH leachate stream, adsorb the aurocyanide anion via exchange for the resin's chloride counter-ion:
XxxNR3 *X + Au(CN)2 xxx NR3 * Au(CN)2 + X
再藉由更強的陰離子樹脂或是用其它的化學(xué)反應(yīng), 將吸附的金洗滌出。通常最經(jīng)濟實惠的替代反應(yīng)是用氰化鋅或是用硫代氰酸鹽將金洗出, 如下:
Elution of the adsorbed gold complex can be accomplished by displacement with a more strongly adsorbed anion or by chemical reaction. Competitive displacement is typically done with either zinc cyanide or thiocyanate:
XxxNR3*Au(CN)2 + SCN+ xxxNR3*SCN + Au(CN)2
XxxNR3*Au(CN)2 + Zn(CN)42+ [xxxNR3*]2 Zn(CN)4 + 2 Au(CN)2
不管以上是用何種方法洗滌出金錯化物,此強酸型陰離子樹脂最終都必須用硫酸或硫酸鐵將其轉(zhuǎn)換回硫酸鹽型式,以利下一次的金吸附的反應(yīng)機構(gòu)模式。其回復(fù)的反應(yīng)機構(gòu)如下:
In either case, the resin must then be converted back to the sulfate form prior to return to adsorption service, typically with sulfuric acid or ferric sulfate. however, the preferred method of elution is by chemical reaction with thiourea:
XxxNR3*Au(CN)2 + SC(NH2)2 + 2H2SO4 xxxNR3*HSO4 + 2 HCN
+ [ Au {SC(NH2)2}2] + HSO4-
b) 弱堿型陰離子交換樹脂的應(yīng)用:
另一種是用弱堿型的陰離子交換樹脂。由于此弱堿型的陰離子樹脂都是以自由基型式存在, 所以必須先用酸處理之后, 再用來吸附金。其反應(yīng)機構(gòu)如下:
b) WEAK BASE ANION:
An alternative approach to the above is the use of weak base anion exchange resins which, because they are normally supplied in the "free base" form, need to be treated with acid prior to contact with the leachate stream. A typical cycle is conceptually as follows:
XxxNR2 + HX xxxNR2H*X-.
XxxNR2 H+X + Au(CN)2 XxxNR2 H+Au(CN)2 +XXxxNR2
H+Au(CN)2 + NaOH XxxNR2 + Na+Au(CN)2 + H2O
因為弱堿型陰離子的高交換容量及可以得到較高的處理量, 于小型的操作系統(tǒng)模式, 通常都會用焚燒來取代洗滌的方式來回收金。
Because of the high capacity available with ion exchange resins and the high loading that can therefore be obtained, in most small scale operations it is often an option to consider incineration of the loaded resin rather than elution.
通常弱堿型陰離子交換樹脂最被常用于此貴金屬回收。
Commonly the Weak base anion ion exchange resins are used for this application
建議杜笙/ Tulsion®離子交換樹脂型號:
RECCOMENDED TULSION PRODUCT :
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產(chǎn)品/ PRODUCT 型式/ TYPE
Tulsion® A-23 AU 強堿凝膠型陰離子具有四級銨官能基
A strong base gel-type resin containing quaternary-amine functional groups
Tulsion® A-27MP 強堿巨孔型陰離子具有四級銨官能基
A strong base macro porous resin containing quaternary-amine functional groups
Tulsion® A-2XMP S 弱堿巨孔型陰離子具有四級銨官能基
A weak base macro porous resin containing tertiary amine functional group