Arsenic pyrite gold mine is one of those awkward, gold was mainly fine and very fine granular disseminated native gold in sulfides, especially arsenopyrite, Pingjiang gold fall into that category. The gold concentrate contains about 100g/t of gold, about 20% of arsenic and sulfur, and most of the gold (more than 80%) is present in the sulfide inclusions, which brings difficulties to the gold leaching process. After a series of tests and analysis, the reason for the high gold content in the leaching residue has been basically clarified, mainly because the fine fine particles of gold originally embedded in the arsenopyrite are partially calcined after calcination. - Iron oxide wrapped. It is considered by chamber-pH thermodynamic analysis that it is feasible to leach gold by liquid chlorination. Table 1 Direct chlorination leaching gold results of high sulfur containing calcine condition result Description Liquid to solid ratio Time / h Chlorine progress Leaching /% Infusion / ( g·l -1 ) Au/ ( g·t -1 ) S Slag rate Gold leaching rate HCl Cl SO 4 2- Fe 3+ Fe 2+ Au/ ( mg·L -1 ) 　 4 SLOW 143 4.14 87.5 14.3 39.5 61.9 31.97 26.93 - 10.44 The filtrate has no chlorine 2 6 fast 21.0 0.84 65.73 90.6 53.71 143.2 73.04 74.39 0.22 66.14 Slightly chloriney 　 8 fast 20.0 0.20 67.07 90.8 18.36 171.6 82.05 93.83 1.12 66.28 Slightly chloriney In the table, the latter two kinds of leaching residue contain about 14g/t of gold, and after the second leaching, the calcined sand is reduced to 10.8g/t, which is equivalent to the result of low-sulfur roasting and leaching gold, and the total gold leaching rate is 92.6%. Table 2 Results of primary chlorinated leaching acid leaching iron - liquid chlorination leaching gold Acid leaching conditions Acid leaching result Total effect of secondary chlorine leaching (relative to baking) Acid to material ratio Liquid to solid ratio Temperature / °C Time / h Slag rate /% Au/ ( g·t -1 ) Fe/% Iron leaching rate /% Total slag rate /% Total leaching rate /% Folding calcine Au Fe Au/ ( g·t -1 ) Fe/% 1 2 90 10 57.79 20.5 22.38 61.11 54.38 95.47 66.6 5.1 12.04 1.5 95 42.18 30 6.35 92.57 39.31 97.32 93.2 3.54 2.45 Table 3 The state of embedding of gold in the slag Sample name Content / ( g·t -1 ) Test / ( g·t -1 ) Iron phase /% m Monomer gold Sulfide inclusion gold Acid soluble package Insoluble matter package total Fe 2 O 3 Fe 3 O 4 Iron sulfide Iron silicate total Primary chlorination 1.12 0.75 10 0.95 12.82 13 34.72 0.13 0.11 4.13 39.09 2.86×10 -5 Acid leaching residue 25.25 0.75 1 3.75 30.75 30 3.77 0.1 0.045 2.48 6.4 　 Secondary chlorinated slag 3.5 0.75 1 3.6 8.85 9 3.32 0.1 0.045 2.93 6.4 2.92×10 -5 Note: In the table, m is an acid-soluble material wrapped with gold and iron oxide.
Classification of tablet press: Models can be divided into single punch tablet press, rotary tablet press, sub-high speed rotary tablet press, automatic high speed tablet press and rotary core tablet press.
The sheet shape pressed by the tablet press is initially flat circular, and later developed into shallow circular arc and deep circular arc on both sides, which is for the need of coating. With the development of special-shaped tablet press, oval, triangle, oblong, square, diamond, circular ring tablets followed. In addition, with the continuous development of preparations, due to the requirements of compound preparations and timed release preparations, special tablets such as double layer, triple layer and core coating are made, which need to be completed on special tablet press.
Rotary tablet press is a machine which is made of several pairs of die distributed on the turntable to make a circular lifting movement according to a certain track and press the granular material into tablet through the press wheel. And the stamping rod with the rotary table rotating speed ≥60m/min line press is called high-speed rotary tablet press, this high-speed rotary tablet press has a forced feeding mechanism, the machine is controlled by PLC, has the automatic adjustment of pressure, control the weight of the piece, eliminate the waste piece, print data, display fault shutdown and other functions, in addition to the control of the weight difference within a certain range, Quality problems such as missing Angle and loose lobe can be automatically identified and eliminated.
With the development of market demand, the scope of application of tablet press is more and more wide, no longer simply limited to the suppression of Chinese and Western medicine tablets, more widely suppressed health food, veterinary medicine tablets, chemical tablets: such as mothballs, washing blocks, smurf blocks, art powder, pesticide tablets, food tablets: chicken essence block, isatis root block, divine Qu tea block, compressed biscuits.
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1) The effect of direct leaching of gold and sulfur from high-sulfur calcine on the leaching of gold by liquid chlorination shows that chlorine can dissolve iron sulfide, which means that there is a high oxidation potential in the solution, that is, there is a certain excess. In the presence of chlorine, iron (Fe 2+ ) can be sufficiently oxidized to Fe 3+ , while gold can achieve maximum dissolution. Table 1 below shows the results of direct liquid chlorination of gold in the material rotary kiln (containing Au 146g/t, S6.07%).
2) The leaching of gold by sulfuric acid immersion in iron is the relationship between the gold-coated iron and the iron oxide in the residue. The leaching residue is mixed, and then iron is immersed in sulfuric acid, and the acid slag is chlorinated to extract gold. The results are shown in Tables 2 and 3.
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Acid leaching, chlorinated leaching with 1 kg each time; the slag contains Au 13 g/t, Fc 36.04%. After leaching by acid leaching, the gold leaching rate is significantly improved. When the acid ratio decreases to near the theoretical value (the theoretical value is 0.973 5 based on Fe 2 0 3 acid consumption 2.625 g H 2 SO 4 /g Fe), the gold leaching rate decreases significantly with the iron dissolution rate. The decrease is markedly, which indicates that gold and iron oxide are closely related to the residue.
It can be seen from Table 3 that after acid leaching, the acid-soluble coating gold is exposed. Since the m values ​​of the chlorinated leaching slag are very similar, it can be inferred that the gold wrapped in the acid solution is in the iron oxide. in.
It can be seen that even if the mass fraction of sulfide-containing sulfur in the arsenic pyrite calcine reaches 5% or more, the liquid chlorination rate of gold can still reach 90% or more. Liquid chlorination of gold is an effective method for this type of stubborn gold. Its speed is extremely fast. It only needs to be leached for 1 hour, and the gold in the calcination of about 160g/t can be dissolved to the utmost. However, this process also has shortcomings: 1 large amount of oxygen consumption (theoretical consumption Cl: S = 10); 2 will cause the leaching gold speed to be significantly slowed down; 3 the impurities entering the solution - iron will greatly increase and so on, thus Bringing disadvantages to the next step.