You are here:

Geology/gold mining


I was told that there is/are chemical(s)that will dissolve quartz rock in order to get the gold out but wasn't sure if I would be willing to handle it. My question is what are the chemical or chemicals and what are the hazards when using them

The way gold extraction form Quartz is that the gold bearing quartz must be ground to a size of at least 200 Mesh which is about face powder size or less than 0.1 mm (100 m), but sometimes sizes smaller than 710 m are required. There is a tendency for the liberation size of the minerals to decrease over time as the ore bodies with coarse mineral grains that can be separated at larger sizes are depleted and replaced by ore bodies that were formerly considered too difficult.

In the mining industry, the plants where flotation is undertaken to concentrate ore are generally known as concentrators or mills.  These plants generally use froth flotation to remove the gold from the other materials, the ground ore is mixed with water to form a slurry and the desired mineral is rendered hydrophobic by the addition of a surfactant or collector chemical (although some mineral surfaces are naturally hydrophobic, requiring little or no addition of collector). The particular chemical depends on the nature of the mineral to be recovered and, perhaps, the natures of those that are not wanted. As an example, sodium ethyl xanthate ("SEX") may be added as a collector in the selective flotation of galena (lead sulfide) to separate it from sphalerite (zinc sulfide). This slurry (more properly called the pulp) of hydrophobic particles and hydrophilic particles is then introduced to tanks known as flotation cells that are aerated to produce bubbles. The hydrophobic particles attach to the air bubbles, which rise to the surface, forming a froth. The froth is removed from the cell, producing a concentrate ("con") of the target mineral.

The con concentrates the gold about 10 - 12 times.  Lets say that the in sutu (in place) ore was 1oz/ton the concentrate would be about 10oz/ton. The con is sent to a smelter where gold and all other metals is extracted by the means of heat.  

I believe what someone was probably talking about is aqua regia.  Aqua regia is nitro-hydrochloric acid and is a highly corrosive mixture of acids, a fuming yellow or red solution. The mixture is formed by freshly mixing concentrated nitric acid and hydrochloric acid, optimally in a volume ratio of 1:3. It was named so because it can dissolve the so-called royal or noble metals, gold and platinum. In fire analysis the gold sample is heated in a bone curcible to a temperature of about 2500 degrees F and all of the quartz and other materials, except gold and silver are absorbed into the curcible, leaving what is called a bead (it looks like a silver bead) but there is also gold in the bead.  The bead is weighted and dropped into aqua regia in which the gold is dissolved.  The bead is weighted again and the amount of loss is the amount of gold in the sample.  


All Answers

Answers by Expert:

Ask Experts


Joe Norris


I am an economic geologist. An economic geologist does mineral evaluations and appraisals of mineral or mining properties. I can tell you if your deposit has value - remember that a mineral deposit, no matter how good, only has value when mined. Any value assigned to a mineral deposit, in the ground, is only the speculative value that deposit.


I have been a economic geologist for most of my 35 year career. Although I have done work in perhaps 45 states and numerious countries much of my work has been in Appalachian coal, intermountain west gold and silver, and Arizona uranium.

Past President of the Virginia Section of the American Institute of Professional Geologists and a certified geologist in twelve states.

BS Degree from Eastern Kentucky University. Work on MS Degree @ Eastern Kentucky University, Colorad School of Mines & Marshall University Numerious short courses on the value of mineral deposits and how to value same. Also several short courses dealing with the different types of geologic processes; sedimentary, igneous, metamorphic along with the mineral associated with each.

©2017 All rights reserved.