Pressure Oxidation is the use of air or oxygen enrichment at high temperatures. The crystal structure of sulfide ore and some gangue minerals is destroyed under pressure. The wrapped gold is exposed to facilitate the cyanide leaching of subsequent gold. Compared with roasting oxidation and biological oxidation, hot press oxidation has a faster reaction rate. Fast degree, no smoke pollution, strong adaptability, high gold recovery characteristics, by
It is considered to be the most effective pretreatment process.

The test sample is a gold flotation concentrate of an ultra-fine refractory gold mine in China. The mineralogical study shows that the main gangue minerals in this sample are quartz and glow stone, chlorite, biotite and feldspar, the main gold-bearing mineral is pyrite and arsenopyrite, gold are mainly covered with yellow in microscopic invisible form in sulfide minerals such as iron ore and arsenopyrite.

Test Reagent

The main reagents used in the test are sulfuric acid, sodium cyanide, lead nitrate and calcium oxide and calcium hypochlorite, all were analytically pure. Among them, sulfuric acid is used as an acid for raw materials
Calcium oxide is used to neutralize the leaching solution and adjust the leaching residue before cyaniding
Pulp, sodium cyanide for leaching slag cyanide leaching of gold, calcium hypochlorite for cyanide leaching
Harmless treatment of liquid discharge.

Test equipment and method

Pressure Oxidation for Refractory Gold Concentrate

Pressure Oxidation tests were all carried out in a 2 L high pressure reactor. The pulp in the reactor is stirred and mixed by a 3-blade propulsion blade wheel, 2 kw electric heating coil for external heating, stirring speed and the reaction temperature is controlled by a controller. First, the gold concentrate sample is put into reactor.

Add 1 L dilute sulfuric acid solution to the reactor; Then adjust the installation reactor and check air tightness then heat stir. At 60 ° C. first stir acidification for 15 min and remove the carbon dioxide produced by the reaction, after heating to a predetermined temperature, finally supply oxygen for hot press oxidation test. After the hot press oxidation reaction is completed, the heating is stopped and the heating coil outside is removed , the use of natural wind and cooling water for pulp rapid cooling, unloading and the operation of filtration, constant volume, drying and sampling is carried out to combine the solid slag samples. Liquid samples are sent for analysis and testing.

Acid heat Pressure Oxidation is a common pretreatment of refractory gold ores methods.  Pyrite and arsenopyrite in acid system with oxygen and water. Such as high temperature oxidation reaction, gradually converted into the corresponding iron salt, sulfuric acid salt and arsenate, the entire crystal structure is destroyed, and the encased gold is dissociated. The release is conducive to subsequent cyanide gold extraction.