Process method for preparing qualified ore pulp by adding lime into micro-powder bauxite

Abstract

The invention discloses a process method for preparing qualified ore pulp by adding lime into micro-powder bauxite, which comprises the following steps of: weighing the micro-powder bauxite, mixing the micro-powder bauxite with metered circulating mother liquor in a mixer to ensure that the alkali preparation amount of mixed slurry reaches the alkali preparation amount required by Bayer dissolution, and storing the mixed ore pulp in a slurry tank; part of ore pulp in the slurry tank is pumped into the ball mill and metered, lime is weighed and then enters the ball mill synchronously, the ore pulp and the lime are mixed and ground in the ball mill, the ore pulp and the lime are fully mixed, and qualified ore pulp enters a finished product ore pulp tank and then enters a Bayer process dissolution system after the evenly mixed ore pulp is treated through an intermediate pump pool and a hydrocyclone. According to the method, the ore powder and the mother liquor are mixed to prepare the ore pulp, and then the ore pulp and the lime enter the mill together to realize uniform mixing, so that the problem of lime addition in a dry-method powder preparation technology is solved, and the activity of the lime can be fully utilized. The economic value utilization of the high-sulfur ore can be realized, and the problem of shortage of bauxite resources in China is solved.

Description

Technical Field

[0001] The invention relates to a process for preparing qualified ore pulp by adding lime to micro-powder bauxite, belonging to the technical field of alkaline process production of alumina. Background Art

[0002] my country's alumina production capacity accounts for 55% of the world's total, but its bauxite reserves account for only 3% to 4% of the world's total reserves. China is a country with relatively scarce bauxite resources. Therefore, the rational and economical production of alumina using high-sulfur bauxite can effectively promote the sustainable development of China's aluminum industry.

[0003] In the process of treating domestic bauxite with the Bayer process, lime needs to be added to increase the dissolution rate of aluminum, reduce the generation of impurities in the reaction process, and reduce alkali consumption, and technical measures are adopted to make the lime present a suitable chemical state in the corresponding generation link. In the traditional bauxite slurry preparation process, lime is mixed with ore and circulating mother liquor (alkali liquor) in a certain proportion and enters the rod (ball) mill for mixing and grinding, which belongs to wet grinding.

[0004] In the process of using suspended roasting technology to treat high-sulfur (high-carbon, high-organic matter) bauxite, in order to achieve a better roasting effect, a dry powder making (dry grinding) system is required to grind the corresponding bauxite into fine powder, enter the suspended roasting system for oxidative desulfurization, and then mix the desulfurized ore powder with the circulating mother liquor (alkali solution) to enter the subsequent process. In the above links, due to the needs of the desulfurization chemical reaction, lime cannot be added in the dry grinding and roasting links; if lime is added to the mother liquor in advance and mixed with the desulfurized ore powder, it has been proven in practice by large-scale industrial devices that the activity of lime will decrease, affecting the recovery rate of alumina in bauxite, and the alkali consumption will also increase. Therefore, it is a difficult problem for the micro-powdered bauxite produced by non-traditional methods to be mixed with the circulating mother liquor and lime after roasting desulfurization, decarbonization, and deorganic matter, to ensure the activity of lime, and to increase the dissolution rate of aluminum and reduce alkali consumption in the subsequent high-temperature and high-pressure dissolution link. Summary of the invention

[0005] The purpose of the present invention is to provide a process for adding lime to fine powder bauxite to make qualified slurry. The method solves the technical problem of effectively adding lime in the roasting desulfurization dry powder making technology and solves the problem that the original lime addition technology reduces its activity.

[0006] The technical solution of the present invention is a process for preparing qualified slurry by adding lime to fine powder bauxite, comprising the following steps: S10. Mixing slurry: first weigh the micro powdered bauxite and mix it with the measured circulating mother liquor in a mixer to ensure that the alkali content of the mixed slurry reaches the alkali content required for Bayer dissolution. After mixing, the slurry enters the slurry tank for storage; S20. Grinding lime addition technology: that is, part of the slurry in the slurry tank is pumped into the ball mill and measured, and the lime is weighed and simultaneously enters the ball mill, where the two are mixed and ground to achieve full mixing of the slurry and lime. After the mixed slurry is processed by the intermediate pump tank and the hydrocyclone, the slurry with qualified particle size enters the finished slurry tank and then enters the Bayer process dissolution system. The slurry with unqualified particle size returns to the ball mill for further grinding.

[0007] In the aforementioned process of adding lime to fine bauxite to prepare qualified slurry, in step S10, the fine bauxite is mixed with the circulating mother liquor using a double-screw mixer; the fine bauxite entering the mixer is transported by an air chute and measured by a rotor scale; the circulating mother liquor entering the double-screw mixer is measured by a flow meter.

[0008] In the aforementioned process of adding lime to fine bauxite to prepare qualified slurry, in step S10, the particle size of the fine bauxite entering the mixer is -1mm≥95%.

[0009] In the aforementioned process of adding lime to fine powder bauxite to prepare qualified slurry, in step S10, the circulating mother liquor NK entering the mixer is 240-245 g / l; the solid content of the slurry after mixing by the double-screw propeller mixer is 200-550 g / l.

[0010] In the aforementioned process of adding lime to a fine powder bauxite to prepare a qualified slurry, in the step S20, a portion of the mixed slurry produced in S10 is metered with lime and then enters an overflow ball mill for joint grinding; the mixed slurry is metered by a flow meter and then pumped into the overflow ball mill; the lime is transported and metered by a speed-regulating quantitative feeder and then enters the overflow ball mill.

[0011] In the aforementioned process of adding lime to fine powder bauxite to prepare qualified slurry, in step S20, the solid content of the slurry entering the overflow ball mill is 200-550 g / l.

[0012] In the aforementioned process of adding lime to fine powder bauxite to prepare qualified slurry, in step S20, the particle size of the lime entering the overflow ball mill is P95-25mm.

[0013] In the aforementioned process of adding lime to fine powder bauxite to prepare qualified slurry, in step S20, the amount of lime added is 8-14% of the dry ore amount.

[0014] In the aforementioned process of adding lime to fine powder bauxite to prepare qualified slurry, in step S20, the solid content of the overflow ball mill discharge is 250-600 g / l; the particle size of the overflow ball mill discharge is -200 mesh ≥85%.

[0015] In the aforementioned process of adding lime to fine powder bauxite to prepare qualified slurry, after the slurry after grinding in step S20 is classified by a hydrocyclone, the solid content of the obtained finished slurry is 250~600g / l; the particle size of the obtained finished slurry is -200 mesh ≥95%; the C / S of the obtained finished slurry is 0.95~1.05.

[0016] Beneficial effects of the present invention: Compared with the prior art, the method of the present invention first mixes the mineral powder with the mother liquor to form a mineral pulp, and then the mineral pulp and lime enter the mill together to achieve uniform mixing, which solves the lime addition problem of dry powder making technology and can make full use of the activity of lime. It can realize the economic value utilization of high-sulfur ore and solve the problem of shortage of bauxite resources in my country. At the same time, its production cost is low and has a greater market competitive advantage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of the present invention.

[0018] In the figure, the solid line part is the fusion technology route involved in the present invention; the dotted line part is the original conventional technical process. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0020] An embodiment of the present invention: A process for preparing qualified slurry by adding lime to fine powder bauxite, comprising the following steps: S10. Mixing slurry: first weigh the micro powdered bauxite and mix it with the measured circulating mother liquor in a mixer to ensure that the alkali content of the mixed slurry reaches the alkali content required for Bayer dissolution. After mixing, the slurry enters the slurry tank for storage; S20. Grinding lime addition technology: that is, part of the slurry in the slurry tank is pumped into the ball mill and measured, and the lime is weighed and simultaneously enters the ball mill, where the two are mixed and ground to achieve full mixing of the slurry and lime. After the mixed slurry is processed by the intermediate pump tank and the hydrocyclone, the slurry with qualified particle size enters the finished slurry tank and then enters the Bayer process dissolution system. The slurry with unqualified particle size returns to the ball mill for further grinding.

[0021] In step S10, the powdered bauxite is mixed with the circulating mother liquor using a double-screw mixer, which is a highly efficient convection mixer that can gently mix the product and ensure high-precision mixing without damaging the material.

[0022] In step S10, the fine powder bauxite entering the mixer is transported by an air chute and measured by a rotor scale.

[0023] In step S10, the particle size of the fine bauxite entering the mixer is -1mm≥95%, that is, the proportion of materials smaller than 1mm is ≥95%.

[0024] In step S10, the circulating mother liquid entering the double-screw mixer is measured by a flow meter.

[0025] In step S10, the circulating mother liquor NK entering the double-screw propeller mixer is 240-245 g / l.

[0026] In step S10, the solid content of the slurry after being mixed by the double-screw propeller mixer is 200-550 g / l.

[0027] In step S20, a portion of the mixed slurry produced in S10 is weighed with lime and then fed into an overflow ball mill for grinding.

[0028] In step S20, the mixed slurry is measured by a flow meter and then pumped into an overflow ball mill.

[0029] In step S20, the solid content of the slurry entering the overflow ball mill is 200-550 g / l.

[0030] In step S20, lime is conveyed and metered by a speed-adjustable quantitative feeder and then enters an overflow ball mill.

[0031] In step S20, the lime particle size entering the overflow ball mill is P95-25mm.

[0032] In step S20, the amount of lime added is 8-14% of the dry ore amount.

[0033] In step S20, the solid content of the material discharged from the overflow ball mill is 250-600 g / l.

[0034] In step S20, the particle size of the overflow ball mill is -200 mesh ≥ 85%, that is, the proportion of materials smaller than 200 mesh is ≥ 85%.

[0035] In step S20, the ore pulp after grinding is classified by a hydrocyclone, and the solid content of the obtained finished ore pulp is 250-600 g / l.

[0036] After the ore pulp is ground in step S20 and is classified by a hydrocyclone, the particle size of the obtained finished ore pulp is -200 mesh ≥ 95%, that is, the proportion of materials less than 200 mesh is ≥ 95%.

[0037] After the ore pulp is ground in step S20 and is classified by a hydrocyclone, the C / S of the obtained finished ore pulp is 0.95-1.05.

[0038] The present invention can ensure that the micro powder bauxite is fully mixed with lime, solves the problem of lime addition in the micro powder bauxite in the roasting desulfurization technology, and can make full use of the activity of lime. The method is a supplement and improvement of the high-sulfur bauxite suspended roasting desulfurization technology, solves the problem of tight bauxite resources in my country, and can fully realize the economic and rational utilization of high-sulfur bauxite resources. At the same time, its production cost is low and has a greater market competitive advantage.

[0039] The above method of the present invention has been applied in actual industrial production and has achieved good results.

[0040] While the invention has been shown and described with reference to the particular embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the claims and their equivalents.

Claims

1. A process for preparing qualified slurry by adding lime to fine powder bauxite, characterized in that: The following steps are involved: S10. Mixing slurry: first weigh the micro powdered bauxite and mix it with the measured circulating mother liquor in a mixer to ensure that the alkali content of the mixed slurry reaches the alkali content required for Bayer dissolution. After mixing, the slurry enters the slurry tank for storage; S20. Grinding lime addition technology: that is, part of the slurry in the slurry tank is pumped into the ball mill and measured, and the lime is weighed and simultaneously enters the ball mill, where the two are mixed and ground to achieve full mixing of the slurry and lime. After the mixed slurry is processed by the intermediate pump tank and the hydrocyclone, the slurry with qualified particle size enters the finished slurry tank and then enters the Bayer process dissolution system. The slurry with unqualified particle size returns to the ball mill for further grinding.

2. The process for preparing qualified slurry by adding lime to fine powder bauxite according to claim 1, characterized in that: In the step S10, the powdered bauxite and the circulating mother liquor are mixed by a double-screw mixer; the powdered bauxite entering the mixer is transported by an air chute and measured by a rotor scale; the circulating mother liquor entering the double-screw mixer is measured by a flow meter.

3. The process for preparing qualified slurry by adding lime to fine powder bauxite according to claim 1, characterized in that: In the step S10, the particle size of the fine bauxite entering the mixer is -1mm≥95%.

4. The process for preparing qualified slurry by adding lime to fine powder bauxite according to claim 1, characterized in that: In step S10, the circulating mother liquor NK entering the mixer is 240-245 g / l; the solid content of the slurry after being mixed by the double-screw propeller mixer is 200-550 g / l.

5. The process for preparing qualified slurry by adding lime to fine powder bauxite according to claim 1, characterized in that: In the step S20, a portion of the mixed slurry produced in S10 is metered with lime and then fed into an overflow ball mill for joint grinding; the mixed slurry is metered by a flow meter and then pumped into the overflow ball mill; the lime is transported and metered by a speed-adjustable quantitative feeder and then fed into the overflow ball mill.

6. The process for preparing qualified slurry by adding lime to fine powder bauxite according to claim 1, characterized in that: In step S20, the solid content of the slurry entering the overflow ball mill is 200-550 g / l.

7. The process for preparing qualified slurry by adding lime to fine powder bauxite according to claim 1, characterized in that: In the step S20, the particle size of the lime entering the overflow ball mill is P95-25mm.

8. The process for preparing qualified slurry by adding lime to fine powder bauxite according to claim 1, characterized in that: In step S20, the amount of lime added is 8-14% of the dry ore amount.

9. The process for preparing qualified slurry by adding lime to fine powder bauxite according to claim 1, characterized in that: In the step S20, the solid content of the material discharged from the overflow ball mill is 250-600 g / l; and the particle size of the material discharged from the overflow ball mill is -200 mesh ≥ 85%.

10. The process for preparing qualified slurry by adding lime to fine powder bauxite according to claim 1, characterized in that: After the ore pulp is ground in step S20 and classified by a hydrocyclone, the solid content of the obtained finished ore pulp is 250-600 g / l; the particle size of the obtained finished ore pulp is -200 mesh ≥ 95%; and the C / S of the obtained finished ore pulp is 0.95-1.05.

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