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. When processing various materials with a vortex device, one of the important factors determining the effectiveness of the method is the amount of material to be treated that coincides with the weight unit of the ferromagnetic particles. During the processing of the concentrate by the vortex device, there are many factors acting on the surface of the material covered by the xanthate film, such as induced current, discharge, local increase in pressure, temperature increase and friction. As a result, the collector is desorbed from the mineral to form a local decomposition.
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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 study was as follows, %: Au 89 g / ton, As 15.0; S 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. The concentrate was weighed 200 g, and the concentrate was placed in a vortex device having a diameter of 100 mm under the conditions of solid: liquid = 1:1, pH: 7.8. The amount of ferromagnetic particles charged was 30 g. In this test, the parameter number of the ferromagnetic particles was not selected as 1/d=8.3 (where 1-length, d-particle diameter was 1.2 mm), and the number recommended by the reference was used. The treated concentrate was immediately fed to a 1 liter flotation machine and butyl xanthate (50 g/ton) was added 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 g / ton (see Figure 1). 
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Insufficient magnetic dipoles in the reaction zone do not guarantee strong agitation of the material and the necessary reaction to the surface of the material. The next step in the handling of the ferromagnetic particles will also have an adverse effect on the subsequent processing of the material.
The results show that the optimal ratio of concentrate (Q) to ferromagnetic particles (P) in the closed circuit system is in the range of 8-12. The preconcentration of the concentrate under Q/P=10 condition and then flotation can obtain a pyrite concentrate with an arsenic content of 2.4%, and the arsenic recovery rate transferred to the pyrite concentrate is 5~ 5.5% (see Figure 2).
When the concentration of hydrogen ions in the slurry is in the range of pH: 5.5 to 10.5, there is no effect on the flotation effect. When flotation in sulfuric acid and lime media, the recovery of arsenic pyrite from arsenic concentrates is 94-95%, and only some of the arsenopyrites can occur in strong alkaline media (pH >10.5). Insignificant inhibition (see Figure 3).
At the same time, after treatment, a portion of the collector that can be resorbed on the mineral surface remains in the slurry and has a detrimental effect on the next preferred flotation. Adding activated carbon (adding 1 kg/ton) during the treatment of concentrate with a vortex device can improve the process index.
The obtained pyrite concentrate (1:40%) contains arsenic 1.7 to 1.8%, so that it can be sent to a copper smelter for treatment. The arsenic concentrate contains 26~27% arsenic and 130g/ton gold. The recovery rates are 95~95.5% and 92~93%, respectively.
Therefore, after the short-time treatment of the gold-arsenic-pyrite concentrate with the vortex device, the preferential flotation effect of the next step can be greatly improved and the arsenic concentrate rich in gold can be stably obtained.
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