At present, China's tungsten ore mud is mostly sorted by re-election method, and the recovery rate of operations is only 30% to 40%. The loss of tungsten from fine mud accounts for about the total loss of each plant. Therefore, further improving the recovery rate of tungsten fine mud has become one of the keys to improve the total recovery rate of tungsten ore beneficiation . In accordance with Chairman Mao’s teaching that “education must be a proletarian political service and must be combined with productive laborâ€, we conducted a flotation test on the tungsten fine mud (containing 0.32% WO 3 ) of the Xiangdong tungsten mine in combination with the graduate graduation practice. . The test work is arranged by mathematical statistics method to find the main contradiction, to find the main reason, to find the best conditions, based on toluic acid as the collector , using branch rough selection, speed selection, thick slurry aeration stirring Waiting for new processes. The preliminary results were obtained: the tungsten concentrate grade was 28.13% WO 3 , the recovery rate was 59.1%, and the enrichment ratio was 91. If the secondary concentrate was combined, the concentrate grade was 23.4% WO 3 , the recovery rate was 70.1%, and the caustic soda was reached. The leaching method produces tungsten trioxide requirements for tungsten concentrate grade (including 20% ​​WO 3 ), making it possible to treat tungsten ore sludge by flotation-water smelting. The following describes some of the trials. I. Mineral sample properties The ore samples were taken from the mixed tungsten ore mud of the fine mud section of the Xiangdong Tungsten Mine Concentrator in December 1975, that is, the tailings of the primary and secondary slime mixed float copper . Contains 0.32% WO 3 . The tungsten minerals are mainly black tungsten ore and scheelite , and the gangue minerals are quartz , feldspar , mica , calcite and fluorite . Since the sampling period is selected from copper production is not normal, mixed with a small amount of ore pyrite, chalcopyrite. The multi-element analysis results of the ore samples are shown in Table 1. The content of -200 mesh in the ore samples is nearly 80%, and the distribution of WO 3 content in each particle size is basically uniform, as shown in Table 2. Table 1 Multi-element analysis results of ore samples
| element | WO 3 | Pb | Cu | Zn | S | Ca | Mg | Na 2 O |
| content(%) | 0.32 | 0.06 | 0.16 | 0.079 | 0.23 | 4.04 | 0.19 | 1.28 |
| element | K 2 O | Fe | Mn | Sn | Al 2 O 3 | TiO 2 | SiO 2 | Cr |
| content(%) | 4.79 | 1.83 | 0.058 | 0.057 | 14.19 | 0.20 | 64.8 | 0.006 |
Table 2 Results of sedimentation and analysis of mineral samples (red is incomplete data)
| Level (micron) | Yield(%) | Grade (WO 3 %) | Distribution rate (%) |
| +150 -150+74 -74+37 -37+19 -19+10 -10 Total | 4.0 18.8 32.0 20.0 8.2 17.0 100.0 | 0.0 0.2 0.2 0.2 0.3 0.2 0.2 | 0.8 19.9 33.9 20.4 11.0 14.0 100.0 |
Second, the best conditions of the first phase of the test, the test arrangement uses mathematical statistics methods to find the main contradictions, to reveal the internal relations, to find the best conditions. A series of tests were carried out using toluic acid, mediline, 731 oxide wax, and styrenephosphonic acid as collectors. The test results show that the above four agents have good harvesting ability for the Xiangdong tungsten ore mud, and the toluene acid is better. The test process flow and the best process conditions are shown in Figure 1.
Fig.1 Optimal conditions of flotation process Closed-circuit test results: concentrate grade 12.5%, recovery rate 78.0%, enrichment ratio 37, separation efficiency 12.3%, good effect, but the dosage is too high (toluene acid 1.2 kg / Tons), the mixing time is too long (50 minutes), it is not easy to produce. Third, the second phase of the new process test is based on the above-mentioned optimal process conditions. In order to further improve the selection index, reduce the dosage of the agent, and shorten the mixing time, we conducted some new techniques. Among them, the effect of branching rough selection and speed selection is better, and the thick slurry aeration stirring is also effective. These are briefly described below. (1) The rough selection of the rough-choice branches is to roughly select the first coarse concentrate and the second raw ore, and the coarse concentrate is roughly selected by the third ore (see Figure 2). It is different from the common rough selection process (that is, it does not branch rough selection, see Figure 3), and its dosage is less than one, and the average dosage is not branched. The comparison results of the rough selection and the non-branch rough selection test are shown in Table 3. It can be seen from Table 3 that the coarsely selected concentrate has a high grade and high sorting efficiency, and the taste of the tailings is similar to that of the non-branched rough selection. Obviously, branch rough selection is better than no branch rough selection, and the dosage is small. Table 3 Branch rough selection and no branch rough selection test results
| Process flow | Grade (WO 3 %) | Crude concentrate recovery rate (WO 3 %) | Sorting efficiency · (%) |
| Raw ore (three averages) | Coarse concentrate | Tailings |
| Tailings 1 | Tailings 2 | Tailings 3 | average |
| Branch rough selection | 0.30 | 3.05 | 0.03 | 0.05 | 0.03 | 0.037 | 89.02 | 3.15 |
| No branch rough selection | 0.28 | 2.45 | - | - | - | 0.034 | 89.78 | 2.40 |
· Sorting efficiency
Figure 2 Branch rough selection process
Figure 3 Why does the rough selection of the rough branching process for the low grade mineral mud better than the normal roughing? Through preliminary experiment observation, the following points have been realized. 1. Artificially increase the grade of selected ore. Tungsten ore is difficult to choose, and its low grade is one of the reasons. Adding the former rough-concentrated concentrate foam to the second ore of the original ore, the sub-investment is considered to improve. For example, the first selected grade of Xiangdong tungsten mine is 0.3%, the first concentrate foam is added to the second branch, the second grade is selected to be about 0.5%; the second concentrate foam is added to the third branch. The third selected grade has increased to around 0.7%. In our experiments, it is more appropriate to divide it into three. 2. Save the dosage of the drug. There are many residual chemicals in the concentrate foam, which can be added to the next one, which can save a lot of foaming agent. (Our test proves that the second foaming agent can only be used in 1/2 of the rough selection. The third one can basically not be added. At the same time, the collector and activator can be reduced accordingly; avoiding the harm of excess pesticides is beneficial to the improvement of sorting efficiency. 3. Improve foam structure and mineral ion composition. The former concentrate foam is added to the secondary branch, and the foam structure and the slurry ion composition of the secondary branch are different from those of the usual flotation. Observed from the phenomenon, the adverse effects of the mud cover mixing during the mineralization process are weakened. (II) Selection of speed selection When we used Medillin and toluic acid as collectors, we found that the grade of coarse concentrate which floated in the first few minutes was high, and the foam grade gradually decreased with the extension of flotation time. This is essentially a question of flotation speed. At the same time, it is felt that the tungsten ore mud coarse selection enrichment ratio and recovery rate are quite high, but the selection efficiency is very poor, and the coarse concentrate grade is difficult to further improve. The method of speed selection is: batching and scraping in rough selection, combining according to the principle of equal grade and equal flotation speed, and selecting multiple times (see Figure 4, I). Let the flotation speed as soon as possible, avoiding the concentration of mixed and reducing quality. It differs from the selection of the speedless selections (Figure 4, II).
Figure 4 shows the test results of the speed separation and non-separation selection. As can be seen from Table 4, the recovery rate and sorting efficiency of the speed selection are high, and the speed selection is better than the speed selection. Table 4 Test results of selected speed and no speed selection
| Process flow | Selected grade (WO 3 %) | Concentrate grade (WO 3 %) | Recovery rate (WO 3 %) | Sorting efficiency (E%) |
| Speed ​​selection | 3.05 | 28.13 | 72.94 | 23.97 |
| No speed selection | 2.81 | 25.82 | 56.87 | 16.75 |
Why does the speed selection improve the selection efficiency? Our preliminary experimental observations: 1. The grade of foam concentrate is related to the mineral content of the target in the tank. At the beginning of the flotation, the foam products of the money for a few minutes had a higher grade. At the end of the flotation, most of the scraped mud was mudstone mud, and the grade was very low; ε was related to the “flotation dynamics†and “flotation speed equationâ€. The basic concept of (dε/dt) is consistent. 2. The selection of the speed selection makes the “bubble with high float and high float†and “bubble with low float and low float†be further selected separately, which is more reasonable. 3, the speed selection is selected according to the speed, respectively, can use less selected agents. Our tests have shown that in general selection, oxalic acid is added as an inhibitor, toluene acid is added for re-acquisition, and a foaming agent is added. However, the speed selection is suitable for the selected conditions due to the different foaming conditions of different floating speeds, and the selection purpose can be basically achieved without adding or adding chemicals. The selection of speed separation involves many theoretical problems, and it is necessary to gradually raise awareness in industrial production. (3) Thick slurry aerated stirring flotation This was discovered during the trial and error process. In the test, it was found that using the same type of XFD impeller agitation flotation machine, using 500 grams of ore sample, floating in a 1 liter tank, the effect of flotation in a 1.5 liter tank is better than using a 1000 gram sample. The effect of flotation in the 3 liter trough is better. It has been repeatedly proved that thick slurry agitation is advantageous for flotation. When stirring with toluene citrate and a little aeration, the mixing time can be shortened. This was discovered by the accidental phenomenon of a new flotation valve leaking. After adding toluic acid by a valve-sealed flotation machine, it was found that it was stirred for 40 minutes before the gray-black foam appeared, and the foam layer became black after 50 minutes. At this time, the flotation effect was good (the stirring time condition test showed 50 minutes). the best). However, when trying a new flotation machine, it was found that gray-black foam appeared in about 8 minutes, and the foam color became black in 10-15 minutes. After that, the foam gradually disappeared. After stirring for 50 minutes, the flotation was very bad. Mixing for 10 to 15 minutes, the flotation effect is similar to the previous stirring for 50 minutes (still slightly higher). After checking, the valve of the new flotation machine has air leakage, and it takes 50 minutes to eliminate the air leakage. Inspired by this discovery, the test was successful and the valve was opened slightly (measured by a flow meter, the intake air amount was 100 ml/min), and the aeration stirring shortened the toluene acid mixing time from 50 minutes to 10 minutes. (4) Branch rough selection and score selection, etc. We have carried out branch rough selection, speed selection, no branch rough selection, no speed selection, branch rough selection, no speed selection, no branch rough selection, Comparative test of four processes such as speed selection. The test results are listed in Table 5. Table 5 Combination test results of several processes
| Process | Concentrate yield (%) | Raw ore grade (%) | Concentrate grade (WO 3 %) | Concentrate recovery rate (%) | Sorting efficiency (%) |
| Branch rough selection, branch selection, rough selection, speed selection, no branch rough selection, no branch selection, rough selection, no speed selection, no branch rough selection, speed selection | 0.66 0.89* 0.61 0.55 0.62 | 0.31 0.30 0.30 0.31 0.30 | 28.13 23.40 21.84 25.82 23.51 | 59.10 70.15* 44.18 45.30 48.51 | 21.34 21.05* 12.31 14.97 14.66 |
* It is the combined index of concentrate and secondary concentrate. It can be seen from Table 5 that the sorting efficiency of branch rough selection and speed selection is the highest (21.34%); followed by branch rough selection, non-speed selection, sorting efficiency It is 14.97%; once again, it is not branch rough selection and speed selection, the sorting efficiency is 14.66%; the sorting efficiency without branch rough selection (that is, the common flotation process) is the worst, only 12.31%. That is to say, the branch rough selection and the speed selection are the best; the branch rough selection improves the coarse concentrate grade, and the speed selection can improve the concentrate recovery rate.
Figure 5: Branch rough selection, speed selection process conditions, foaming time (minutes), float sulfur floating tungsten are 1 liter flotation tank branch rough selection, speed selection process and process conditions are shown in Figure 5. The tungsten ore mud ore is pre-floated with sulfide minerals (the same conditions), the latter branches are coarsely selected (floating tungsten), and the speed is selected separately; the slurry concentration is 45% (solid weight) during rough selection, and slightly inflated when adding toluene acid. 100 (ml / min). When the branch is roughed, the dosage is reduced one by one, and the roughing time is slightly longer than one. At the time of selection, the volume of the flotation tank was adapted according to the change in the foaming volume of the batch scraping, and the three selections were not added. The test at this stage was carried out at a lower temperature (10 ° C or below). In the autumn, winter and spring temperatures, the indicators fluctuated little, indicating that the future production will not be affected by the seasonal temperature. (V) The results of new process tests such as rough selection, speed selection, and thick slurry aeration show that: the use of branch rough selection and speed selection can save the dosage. The collector toluic acid was reduced from 1.2 (kg/ton) to 0.8 (kg/ton), the activator
lead nitrate was reduced from 0.7 (kg/ton) to 0.6 (kg/ton), and the foaming agent No. 2 oil was 40. (kg / ton) down to 20 (kg / ton), the inhibitor oxalic acid and dispersant water glass can be used; with a thick slurry aeration, the stirring time of toluic acid is shortened from 50 minutes to 10 minutes; The easy process has achieved a good index. The concentrate grade is 28.31% WO
3 , the recovery rate is 59.1%, and the enrichment ratio is 91. If the secondary concentrate is combined, the concentrate grade is 23.4% WO
3 , and the recovery rate is 70.2. %, the sorting efficiency increased from the original (ie common) 12.99% to 21.34%. Fourth, the new process needs to continue to improve the improvement of the test method, the adoption of the new process, the flotation of tungsten ore mud has some effects, and new signs have emerged. However, due to our limited manpower, level and conditions, the work has just begun and needs to be further improved. The selection indicators have to be further improved. Whether the tungsten flotation can be realized in the industry, the cost of the medicament is a problem, and it is necessary to continue to reduce the dosage of the medicament. Preliminary trial showed that additional secondary collector
(coal oil) can save the amount of sour toluene. Although the above new process is not very complicated, it is used in industrial tests, and many problems that are difficult to find in laboratory tests occur, which are to be found and solved in industrial tests, and are effective in production. At the same time, I hope that everyone will test and correct. (This article and the experimental research work was completed by Hu Weibai and Huang Kaiguo)
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