火试金纯金和纯银用什么试剂？

Fire assaying is the process of concentration of precious metals from non-ferrous ores and estimated either gravimetric or ICP-OES instrument.
The entire process (Analysis of Gold & Silver) consists of three steps:
Separation of elemental gold & silver from ores by formation of lead alloy along with formation of slag for rest of the materials present in ore.
In second step, the lead alloy is heated in stream of oxygen at 950 0C in a cupel using Cupellation furnace when most of the lead is removed as PbO leaving gold and silver in metallic state.
Quantification of metalling gold and silver by either by gravimetry or by ICP-OES or AAS.

Description:
Formation of lead alloy button of gold and silver is done by mixing adequate quantity of ore with a synthetic flux mixture at 1100 0C in PIIT furnace when gold and silver is converted to lead alloy and rest of the ore is separated as slag. The synthetic flux mixture contains Lead oxide, Flour, Fluorspar, Silica, Sodium carbonate & Borax. Second stage is Cupellation of lead button which contains lead with Gold and Silver. Lead is converted to lead oxide, most of which is removed by stream of air blowing through the furnace and rest of lead oxide was absorbed by calcium phosphate

After cupellation, pure gold and silver is treated with nitic acid, when silver dissolves but not gold. The solution containing silver nitrate is filtered off and estimated using ICP-OES instrument for silver content. Gold is left as residue, dissolved in aqua regia and estimated for gold content by ICP-OES.
火试金是从有色金属矿石中提取贵金属的过程，可通过重量分析或ICP-OES仪器进行估算。
Fire assay furnace.

火试金整个过程（金银分析）包括三个步骤：
1、通过铅合金的形成以及矿石中其他物质的熔渣的形成，从矿石中分离元素金和银。
2、铅合金在950℃的氧气流中，在使用灰吹炉的灰皿加热，此时大部分铅以PbO的形式去除，使金和银处于金属状态。
3、通过重量分析或ICP-OES或AAS对金属金和银进行定量。

说明：
当金和银被转化为铅合金，其余的矿石被分离为炉渣时，在1100℃的灰吹炉中，将足够数量的矿石与合成助焊剂混合物混合，形成金和银的铅合金铅扣。合成助焊剂混合物包含氧化铅、面粉、萤石、二氧化硅、碳酸钠和硼砂。

第二阶段是铅扣的杯形化，铅钮中含有铅和金银。铅被转化为氧化铅，其中大部分通过吹入灰吹炉中的气流去除，其余的氧化铅被灰皿璧吸收。