d Gold y Recovery : : : : From e cyanide r liquor USING TULSION ® ® ION EXCHANGE RESIN.
简 介/ / / / INTRODUCTION : : : :
传统上使用活性碳吸附金子。 珍贵的金会被活性碳吸附于表面,再藉由洗涤或直接焚烧以回收金。
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.
使用离子交换树脂回收贵金属比活性碳还具有多方面的优势 , 因为藉由特殊制造过程中 , 我们
可以在其结构上的有效官能基上置入具有选择性的离子 ,以选择性的吸附此贵重金属 。
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 , 由于具有经济考虑优势 , 离子交换树脂普遍被使用于贵金属回收。而大部份使用阴离子交
换树脂来交换吸附贵金属。
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
用氰化物萃取金的过程中 , 金会以阴离子的氰化金型式存在 , 既 Au(CN) 2 - ; 再经由强碱或弱
碱的阴离子交换树脂交换回收。如 T T ulsion ® ® ® ® A-23（强碱）, T T ulsion ® ® ® ® A-27mp（强碱）及
T T ulsion ® ® ® ® X A-2X p mp (弱碱) 。
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 T T ulsion ® ® ® ® A-23, T T ulsion ® ® ® ® A-
P 27MP and T T ulsion ® ® ® ® A-2XMP
) (a) 用 强碱离子交换树脂方面的应用 : : : :
此型的强碱型阴离子树脂具有四级铵的官能基 ,在高 pH 值的溶液中 ,藉由交换氯离子的相反离子
来吸附 Au(CN) 2 - ; 其反应机构如下 :
) (a) STRONG E 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:
XxxNR 3 *X +Au(CN) 2 xxx NR 3 *Au(CN) 2 + X
再藉由更强的阴离子树脂或是用其它的化学反应 , 将吸附的金洗涤出 。通常最经济实惠的替代反
应是用氰化锌或是用硫代氰酸盐将金洗出 , 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:
XxxNR 3 *Au(CN) 2 + SCN + xxxNR 3 *SCN +Au(CN) 2
XxxNR 3 *Au(CN) 2 + Zn(CN) 4
2+
[xxxNR 3 *] 2 Zn(CN) 4 + 2 Au(CN) 2
不管以上是用何种方法洗涤出金错化物 ,此强酸型阴离子树脂最终都必须用硫酸或硫酸铁将其转
换回硫酸盐型式 ,以利下一次的金吸附的反应机构模式。其回复的反应机构如下 :
In either case, the resin must then be converted back to the sulfate form prior to
return to adsorption service, typically with c sulfuric acid r or ferric sulfate.
however, the preferred method of elution is by chemical reaction with thiourea:
XxxNR 3 *Au(CN) 2 + SC(NH2) 2 + 2H2SO4 xxxNR 3 *HSO4 + 2 HCN
+ [ Au {SC(NH2)2}2] + HSO4-
) b) 用 弱碱型阴离子交换树脂的应用 : : : :
另一种是用弱碱型的阴离子交换树脂。由于此弱碱型的阴离子树脂都是以自由基型式存在 , 所以
必须先用酸处理之后 , 再用来吸附金 。其反应机构如下 :
) b) K WEAK E 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:
XxxNR 2 + HX xxxNR 2 H*X-.
XxxNR 2 H + X +Au(CN) 2 XxxNR 2 H + Au(CN) 2 +X -
XxxNR 2 H + Au(CN) 2 + NaOH XxxNR 2 + Na + Au(CN) 2 + H2O
因为弱碱型阴离子的高交换容量及可以得到较高的处理量 , 于小型的操作系统模式 , 通常都会用焚烧来
取代洗涤的方式来回收金 。
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.
通常弱碱型阴离子交换树脂最被常用于此贵金属回收 。
Commonly the Weak base anion ion exchange resins are used for this application.