Jinchuan nickel ore beneficiation product plan and two product flotation process

Exchanging views Hu Xigeng Zeng Xi (Jinchuan)

First, the relationship between the nature of the ore and the product plan

Jinchuan ore, the primary metal minerals: Nickel pyrite, yellow copper ore, pyrrhotite and other minerals three closely associated, each package, interspersed with students is very common, and some form pentlandite The flaming, snowflake, feather, and needle are produced in pyrrhotite and are finely embedded. There is still 1.09% nickel in the pyrite "single mineral". This makes mineral sorting difficult and the quality of the product is not high. Estimated according to the estimated values ​​in Table 1:

Table 1 Minerals and element content (estimated value)%

(1) A product plan, namely A+B+C, a concentrate consisting of three pure minerals. When the nickel recovery rate is 100%, the best concentrate yield is 4.4+3.0+10=17.4%. The concentrate nickel content is:

However, it is known, generally only about 80% of a pure mineral concentrate grade products, such as galena containing Pb 86.6%, a product claim lead concentrate containing Pb 70% (86.6% × 81 %); sphalerite containing Zn 67%, the first grade of zinc concentrate requires 55% Zn (=67%×82%). Therefore, the nickel concentrate grade of a product scheme can only be 8.6%×80%=6.9%. This may be because the grade of nickel concentrate in the field has been hovering around 6%. For many years, the experimental research work of a product program is difficult to obtain high recovery rate and the nickel concentrate is >8%. Of course, if the content of pyrrhotite and chalcopyrite in the ore is reduced, or the nickel recovery rate is allowed to be reduced, it is still possible to increase the nickel concentrate grade.

(2) Two product plans, namely A+B is the first product and C is the second product. Because A and B are closely symbiotic and floatable, the best concentrate yield is 7.4%, the grade is 18.9%, and the nickel concentrate grade is higher, generally not more than 15% (=18.9). %×80%). However, the recovery rate is not very high. Because the recovery rate of nickel in product C is more than 6.8%, and the tailings usually lose about 10%.

(3) The three product schemes, namely A, B and C, are separated. The product A nickel concentrate has a high grade, above 24%. Because nickel is lost in each product, the recovery rate is not high, and the three minerals are closely symbiotic. Some are inlaid with fine particles, so the magnetic separation fails to work. The premise of flotation can only be fine grinding, as well as the prescription and separation process for finding special effects. The calculation results of each product plan are shown in Table 2.

Table 2 Estimated results of each product plan (%)

The gangue minerals in the ore: serpentine, olivine, pyroxene, amphibole, talc, chlorite, magnesium-containing minerals are, they account for 70% of the mineral content of the ore in the left and right, a relatively low hardness, Easy to mud; as long as the beneficiation process and prescription are not appropriate, separation is difficult and easy to get up and floating, which is why nickel concentrate contains high magnesium.

Since the ore minerals (including useful minerals and gangue minerals) composition, disseminated, relations are very complex mosaic, useful components associated platinum group elements such as range, to get good separation and recovery of reasonable, it seems to be required A special set of techniques and prescriptions.

Second, the process characteristics of this study

The process characteristics of this study are: one fine grinding, strong stirring and dispersion, selective inhibition, activation, and harvesting. After one rough selection, one selection, one sweep, and one float in the weak alkaline medium. Flotation process to obtain two products that meet the requirements.

(a) a fine grinding

The results of coarse selection of one grinding flotation are shown in Table 3. The sorting efficiency E is used as a criterion in the table. In the formula - concentrate recovery rate, - concentrate yield, - the original ore grade, - pure mineral grade, pure nickel pyrite containing Ni, taken here =31%. In addition to the common grades and recovery rates, the results of this study evaluated the test results using the overall efficiency E (the same below). It is known from Table 3 that a fine grinding to 94.2%-200 mesh can achieve higher sorting efficiency. Another research report also shows that the monomer dissociation degree of sulfide minerals is only 73.4% when the ore mill is ground to 70%-200 mesh. It can be seen that in order to obtain a good sorting effect, fine grinding to the dissociation of mineral monomers is a prerequisite. Because mineral processing is a mineral sorting, the sub-requisite is the key.

Table 3 Relationship between grinding fineness and flotation efficiency (%)

(2) Strong mixing

Strong agitation is carried out in a special container, which plays a very good role in the flotation of nickel ore, see Table 4. Obviously, with the increase of stirring time, the nickel recovery rate in the flotation foam is gradually increased, the quality of the concentrate is correspondingly increased, and the amount of MgO is correspondingly reduced. After strong stirring for 30 minutes, after flotation and coarse selection for 2 minutes, a qualified nickel concentrate can be obtained with a nickel grade of 11.02% and a recovery rate of 66%. Flotation for 30 minutes, the total recovery rate was 91.0%. The effect of strong agitation, the possible explanation is: strong agitation can disperse the slime, promote the drug effect, promote hydrophobic association, and have the functions of carrier, coagulation and intermediary.

Table 4 Effect of strong mixing time on flotation rough selection (%)

Note: The ore contains 1.69% nickel.

(3) Weak alkaline medium flotation

The ore's natural pH value is 8.86, the flotation effect is not very good, adding acid or alkali to adjust the slurry, the flotation index can be improved, see Table 5. It is obvious that the flotation effect is best in a weakly alkaline slurry with a sodium carbonate dosage of 2400 g/ton and a pH of 9.94.

Table 5 Relationship between pH value of slurry and flotation effect

From the results of the surface zeta potential measurement of ferronickel and serpentine by the chief engineer of Dong Nailiang (see Figure 1), it can also be seen that at the pH of about 7, the surface of the pentlandite (curve 1) surface The lowest potential (about -40mV) and serpentine (curve 3) have the largest difference in surface zeta potential (-0mV). Serpentine is easy to electrostatically adsorb on the surface of pentlandite, which is not conducive to sorting; but acidic or alkaline. In the medium, the potential difference between the two minerals is small, the pH is 3 and 12, and the surface potentials of both are equal, so it is not easy to generate electrostatic adsorption, which is favorable for sorting. Therefore, pentlandite has good flotation effect in weakly acidic or weakly alkaline pulp, especially in weak alkaline pulp, which is convenient for production management and is conducive to improving product quality.

(4) Selective activation, inhibition, and collection

As shown in Fig. 1, after the addition of the activator CuSO ₄ , the zeta potential of the pyrite (curve 2) is very stable between -25 and -20 mV, and the zeta potential of the serpentine surface after the addition of the inhibitor CMC (curve 4) It is very similar between -20 and -35 mV, and the two are repelled by the same sex, which is not easy to produce slime adsorption and is favorable for sorting.

In this study, several collectors with better selectivity to pentlandite than butyl xanthate were used : SN, AX, IBX, etc. Their flotation effect is better than butyl xanthate (see Table 6), SN is superior.

Table 6 Comparison of several highly selective collectors and butyl xanthate flotation

(5) One of the simplest open flotation processes

In this study, a single simple flotation open-circuit test procedure (see Figure 2) with one-time fine grinding, strong agitation, one rough selection, one selection, one sweep, and a medium mine re-float is used (see Figure 2). cycle. When the ore contains 1.69% nickel, 1.15% copper and 27.81% magnesium oxide, two qualified products can be obtained with different prescriptions: nickel concentrate (concentrate I) and nickel-containing pyrrhotite (concentrate II) ). The indicators are shown in Table 7.

Table 7 Test results of several sets of prescriptions (%)

The composition of the first prescription (SNa) is (g/ton): sodium carbonate 3200, copper sulfate 500, ammonium sulfate 160, water glass 1380, CMC 10, SN 240, IBX 100, pine oil 130.

Third, the conclusion

(1) According to the mineral composition and embedding characteristics of the ore in Jinchuan No. 2 Mine, the comprehensive analysis shows that it is difficult to further improve the nickel concentrate grade by using the existing one product scheme. The use of two product solutions can significantly improve the grade of nickel concentrate, reduce the amount of concentrate, and double the processing capacity of existing nickel smelting furnaces, bringing more benefits to enterprises. The three-product solution maximizes the nickel concentrate grade, but the nickel recovery rate is significantly reduced, and special effects and processes are required.

(2) This study gives an extremely simple and effective single flotation process: one fine grinding, strong agitation dispersion, selective inhibition, activation, and collection. After rough selection and one selection in weak alkaline pulp. One sweeping and one mine in the middle mine, and two qualified products of nickel concentrate and nickel-containing pyrrhotite can be obtained by using several sets of prescriptions.

This article was published in the 1990.2nd National Nonferrous Metals Mineral Processing Academic Conference, anthology P.257-261 ☺

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