Separation of gold-arsenic-pyrite by flotation after pretreatment in the vortex layer

Some metal ore Dan Zhonggui was fine shape disseminated in arsenopyrite and iron pyrite. Currently, in the development of a process for recovering gold and silver from such ores, it is necessary to pre-decompose sulfides by calcination, autoclave oxidation or bacterial leaching.

In order to reduce the amount of material to be calcined and to increase the gold grade in the material (in most cases, gold and arsenic pyrite coexist), the mixed concentrate flotation should be separated into arsenic concentrate and pyrite concentrate.

The arsenic - Theoretical basis Tomb various methods pyrite concentrate pyrite God pyrite and an oxidizing agent (lime, soft manganese ore, potassium permanganate, etc.) under the action of their different oxidation surface. However, all of these pharmaceutical methods have the following disadvantages: strict compliance with the pharmaceutical system is required. Otherwise, small changes will cause a sensitive reaction, and the collector needs to be removed from the concentrate and the subsequent flushing will cause the solid to overflow. Losses and new agents must be supplemented to purify and neutralize to reduce the harmful effects on the environment.

In recent years, in order to enhance the dispersion process and surface activation process of the material to be treated, equipment with a vortex layer has been utilized. The mechanism of action and equipment structure of such equipment can be found in the technical literature.

The dry or slurry-like material is subjected to intense agitation of the ferromagnetic particles and in this case is subjected to electric and magnetic fields, induced currents and their discharge, acoustic vibration, activation and temperature.

The process of action in the vortex device can be either intermittent or continuous. The ferromagnetic particles are not carried away from the reaction zone by the liquid stream or gas stream, but remain in the magnetic field. In order to carry out the batch test, a sealed cup made of non-magnetic steel was placed in the reaction chamber for testing.

The composition of the flotation concentrate used in the experimental research is as follows, % : Au 89 grams / ton, As15.0 ; S ₂ 0.32 ; FeO 1.43 ; Fe ₂ O ₃ 32.11 ; Al ₂ O ₃ 8.1 ; SiO ₂ 23.80 ; TiO ₂ 1.34 .

In the absence of pre-treatment by the vortex device, multiple tests for the separation of the mixed flotation concentrate did not achieve good results. In a basic medium when the flotation of copper and sulfuric acid with lime, preferably in the case of arsenic in pyrite product from 12 to 13% to 5%, arsenic recovery of arsenic into the concentrate 35% .

Later, the concentrate was pretreated with a vortex device, and the concentrate was subjected to flotation separation. Weigh concentrate 200 grams The concentrate was placed in a vortex device having a diameter of 100 mm under the conditions of solid: liquid = 1 : 1 and pH : 7.8 . The loading amount of ferromagnetic particles is 30 grams . In this test, the parameter number of ferromagnetic particles like 1/d=8.3 ( 1- length here , d- particle diameter 1.2 mm) was not used, and the number recommended by the reference was used. The treated concentrate immediately gives the volume 1 liter And add butyl xanthate to the flotation machine ( 50 grams / ton) for flotation.

The data obtained prove that when the treatment time reaches 10~11 minutes, the content of arsenic in pyrite products is reduced from 16% to 4% . When the yield of arsenic concentrate is about 62% , the recovery rate of arsenic transferred into Shen concentrate is 89~90% , the recovery rate of gold is 90~91% arsenic, and the gold grade is 23~24% and 125~ respectively. 130 grams / ton (see Figure 1 ).