Alkaline separation flotation of barium sulfide-toxic sand

Huang Kaiguo Li Longfeng Hu Weibai Zhang Guoxiang

Antimony concentrate containing less than 1.0% arsenic requirements. However, according to the investigation of 11 mines and ore products in China, there are 7 mines with antimony concentrates (63%) containing more than 1% arsenic, some as high as 4%, unqualified products, difficult sales, and even discontinued production. The antimony concentrate contains high arsenic, resulting in high smelting alkali consumption, long cycle, low recovery rate, high cost and serious environmental pollution. Therefore, the reduction of arsenic in antimony concentrate is an urgent problem to be solved. This paper focuses on the results of research on the flotation of sulphide sulphide-alytic sand in weakly acidic pulp and separation flotation in alkaline pulp.

1. Mineral samples and test methods

Arsenic, antimony ore sample is mainly metallic minerals stibnite, arsenopyrite, pyrite and the like. Gangue minerals as quartz, sericite and the like. The ore contains 5.12% bismuth and 0.45% arsenic, and is processed to -3 mm for testing according to the conventional sample preparation method. The small test is milled with XMQ ball mill and coarsely selected in XFD type 1.5 liter single tank flotation machine. Separation of arsenic and arsenic in 1 liter single tank flotation machine and 100 gram hanging tank flotation machine (selection) .

The pure minerals required for the micro-flotation test are selected from the above-mentioned ore and the bulk stibnite and arsenopyrite are prepared according to the usual pure mineral processing method, and the strontium ore (mineral content 96.8%) of -80+200 mesh size is obtained respectively. And arsenopyrite (mineral content 97.8%) for testing. The microflotation test was carried out in a modified Harrison tube (single bubble tube) with an aeration of 17.5 ml/min.

Second, the test results and analysis

(1) Pure mineral test

Under conditions and without the addition of copper sulfate, copper sulfate, butyl xanthate with 10 mg / l, flotation results under different pH of the medium shown in Figure 1.

It can be seen that when copper sulfate is not added, the floatability of the arsenopyrite at different pH values ​​is very close to that of the stibnite, that is, it is well floated in an acidic and weakly acidic medium, and is inhibited in an alkaline medium.

However, when a small amount of the activator copper sulfate is present, the activated arsenopyrite floats well in an alkaline medium. Stibnite and in alkaline medium, due to its dissolution behavior of the surface is not conducive to activation and Cu 2 + xanthate collectors are still inhibited. Both are expected to be separated in an alkaline medium.

(2) Flotation test of arsenic-containing antimony ore

1. Slurry pH test

The arsenic-containing antimony ore is ground to 62%-200 mesh, and the dosage is 160 g/ton of lead nitrate, 800 g/ton of butyl xanthate, and 30 g/ton of pine alcohol. The flotation results at different medium pH are shown in Fig. 3. . It is also shown that both of them are very buoyant in the acid slurry, but as the pH of the pulp increases. The recovery rate of cockroaches drops sharply, while the toxic sand is better. Therefore, it is possible to perform separate flotation in alkaline pulp.

Table 1 Factors and levels of prescription test (g / ton)

Table 2 L 8 (2 7 ) Factorial Test Arrangement and Results (%)

2, prescription tuning test

The prescription adjustment experiment was based on orthogonal design, see Table 1. And strive to obtain better indicators when the amount of yellow medicine is low. The test results are listed in Table 2. Test criteria using 锑 sorting efficiency

Ε-recovery rate, %; γ-concentrate yield, %; α-original grade, %; βm-target mineral content of a metal, stibnite containing strontium according to 71.4%. As can be seen from Table 2, the effects of A (sulfuric acid) and C (butyl yellow drug) are significant, and the dosage is preferably increased. The AC interaction effect is also obvious and may be related to the easy decomposition of xanthate in acidic media. B (lead nitrate) has little effect. The eighth point is the best among the pilots. That is, when the amounts of sulfuric acid, lead nitrate, and butyl xanthate are 2,500, 160, and 500 g/ton, respectively, the sorting efficiency is 93%, the highest.

However, we do not want to increase the amount of yellow medicinal products, and increasing the amount of sulphuric acid will accelerate the decomposition of xanthate, which may not be beneficial for the next alkaline pulverization and bismuth-arsenic separation flotation. Therefore, the central point test is arranged, that is, between the high and low levels of A, B, and C factors, A is 2000 g/ton, B is 140 g/ton, C is 400 g/ton, and the test results are listed in Table 3. The sorting efficiency is 93%, which is exactly the same as the sorting efficiency of the best pilot 8 in Table 2. Therefore, the central point can be considered as an ideal pilot.

Table 3 Center point test results (%)

3. Iridium-arsenic separation flotation test

The crude concentrate obtained above has a high arsenic content (4.18%) and a low grade (50.57%), which requires separation flotation. According to the above pure mineral and ore pH test, it is expected that the separation of arsenic in the alkaline slurry can be obtained. This test uses sodium carbonate to adjust the slurry, the dosage is 1200, 1600, 2000, 2400 g / ton, respectively, and the selected amount of 3/4 is added to the selected I, 1/4 to the selected II. The test procedure is shown in Figure 4, and the test results are shown in Figure 5. The optimum amount of sodium carbonate is 1600 g/t. At this time, the obtained antimony concentrate contains 58.51%, arsenic 0.48%, and strontium recovery rate 94%; arsenic concentrate contains 24.7% arsenic, 锑6.5%, arsenic recovery rate 80.6%, and achieves the separation of arsenic and arsenic. purpose.

Figure 4 Separation and flotation process and process conditions of arsenic-containing antimony ore

Figure 5 Separation and flotation results of arsenic-containing antimony ore

Third, the conclusion

1. The unactivated stibnite and arsenopyrite are similar in floatability at different pH values, that is, in the acidic and weakly acidic medium, the floatability is good. As the pH value increases, the floatability decreases sharply. The media is not floating well. When there is an activator of copper sulfate or lead nitrate, the floatability of the two in the alkaline medium is different, the poisonous sand is well floated, and the stibnite is inhibited.

2. The arsenic-containing antimony ore is roughly selected in the weakly acidic pulp, and the arsenic and arsenic mixed concentrate is obtained. Then, the arsenic is suspended in the alkaline slurry, and the strontium-arsenic separation flotation is carried out, and satisfactory results can be obtained. If bismuth arsenic minerals are symbiotic, gold minerals may be recovered in arsenic concentrates.

Original article carrier "METALS (MINERAL PROCESSING SECTION)" 1986, №6, P.5 ☺

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