Method for realizing online regulation and control of preparation of alumina ore pulp from imported bauxite by using infrared spectrum

Abstract

The invention relates to the technical field of intelligent analysis of aluminum oxide production, in particular to a method for realizing online regulation and control of preparation of aluminum oxide ore pulp from imported bauxite by using infrared spectroscopy. Carrying out ore blending operation on the aluminum ores with different grades by using an automatic sampler; the aluminum ore is crushed to be below 15 mm through a coarse and fine crushing machine; an infrared spectrum online detection intelligent analysis system is used for analyzing and detecting ore components and guiding ore blending; the bauxite enters a grinding head bin; uniformly mixing the bauxite conveyed from the grinding head bin with the circulating mother liquor, and feeding into a ball mill; carrying out ball-milling molding to obtain alumina ore pulp; components of the aluminum oxide ore pulp are detected and analyzed through manual sampling, and data feedback is conducted; and by comparing and analyzing mutual complementation and mutual approval of data of online detection and manual sampling, ore grade matching is further guided.

Description

[Technical field]

[0001] The invention belongs to the technical field of intelligent analysis of alumina production, and in particular relates to a method for realizing online regulation of alumina slurry preparation of imported bauxite by using infrared spectroscopy. [Background technology]

[0003] With the decline of global ore grade and the widening gap between bauxite supply and demand, the uncertainty of the source and grade of imported bauxite will inevitably increase. The grades of bauxite entering our company's factory and the ore entering the mill are uneven, and the gangue mineral composition has doubled, which puts higher requirements on the timeliness and accuracy of homogenization and ore blending. At present, the ore entering the factory is directly stored without crushing or homogenization yard, which leads to large fluctuations in the quality of the ore entering the production process, which has a great impact on the production dissolution blending and indicator stability. The traditional offline manual sampling and laboratory analysis can no longer meet the adjustment and control of the process.

[0004] The existing sampling and testing of ore entering the mill has the following problems: 1. The ore entering the mill is sampled once every 8 hours, and the mining and processing stage takes 3 to 4 hours. By the time the results come out, they are seriously delayed, and have limited guiding significance for production; 2. The ore entering the mill is analyzed once a week for "effective alumina" and "reactive silicon", which has little guiding significance for ore blending and alkali blending; 3. In view of the uncertainty and lag of the front-end mill blending, the process sampling and analysis of the flash discharge material at the end of dissolution is currently set up every 4 hours, including solution and solid phase component analysis, which can only verify the dissolution effect and whether the front-end ore blending is accurate, but here it is already a result, no matter what the data is, it can no longer be adjusted accordingly.

[0005] Guinea's Boffa bauxite has the characteristics of low silica content (2.5%) and alumina content ranging from 40% to 54%. Although Boffa bauxite has a high alumina content, the effective alumina content varies greatly and is unstable. However, the current ore blending conditions for domestic smelters using imported ore are: ore blending is carried out after testing through manual sampling. The analysis method based on XRF technology has poor representativeness of each batch of samples and delayed results, resulting in large fluctuations in dissolution effects, causing increased raw material costs, affecting the dissolution rate, and thus affecting alumina production. [Summary of the invention]

[0006] In view of the above, it is necessary to provide a method for online regulation of alumina slurry preparation of imported bauxite using infrared spectroscopy. During the preparation of the slurry, the ore blending and alkali solution preparation are guided according to the content of activated alumina and reactive silicon, which can significantly save process alkali consumption indicators and improve the dissolution rate.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for online regulating alumina slurry preparation of imported bauxite using infrared spectroscopy, the method comprising the following steps:

[0009] (1) Unloading the bauxite and sending it to the ore yard via a conveyor belt;

[0010] (2) The bauxite is blended by an automatic stacker and reclaimer, and the iron is removed before crushing. The chemical composition of the bauxite is analyzed by infrared spectroscopy. The crushed material is transported to the grinding head bauxite bin via a discharging belt. The bauxite in the grinding head bauxite bin and the circulating mother liquor sent by evaporation are then sent to a ball mill, where they are ground into a slurry;

[0011] (3) The slurry produced by the ball mill is classified by a cyclone. The coarse sand at the bottom of the cyclone is returned to the ball mill for further grinding. The overflow of the cyclone flows to the rotary screen by gravity. After the light impurities are screened out by the rotary screen, it enters the finished slurry tank to obtain qualified slurry.

[0012] In the present invention, further, the crushing in step (2) is to use a coarse crusher to crush the bauxite to a fineness of less than 50 mm, and to use a fine crusher to crush the bauxite to a fineness of less than 15 mm.

[0013] In the present invention, further, the bauxite in step (1) is imported gibbsite-type bauxite.

[0014] In the present invention, further, in step (2), after crushing and before ball milling, an infrared spectrum online detection intelligent analysis system is introduced to detect the content of effective ingredients in the bauxite.

[0015] In the present invention, further, the ratio of the bauxite to the circulating mother liquor sent by evaporation in the step (2) is adjusted according to the content of the effective components in the bauxite.

[0016] The effective ingredient content includes 13 components such as Al2O3, SiO2, Fe2O3, CaO, K2O, Na2O, SO3, TiO2, attached water, total carbon, organic carbon, activated alumina, and reactive silicon.

[0017] In the present invention, further, the infrared spectrum detection performed in step (2) is realized by an infrared spectrum online detection intelligent analysis system. Specifically, the infrared spectrum online detection intelligent analysis system includes an analyzer, an electrical box and system software.

[0018] The raw materials of the present application method are 100% derived from bauxite imported from Guinea, and as the first alumina enterprise in the domestic industry to introduce an infrared spectrum detection system in quality inspection, it has good advancement and can provide certain reference value and application research for the development of the alumina industry.

[0019] The present invention has the following beneficial effects:

[0020] 1. The present invention can reduce the fluctuation of indicators. The online real-time detection results of ore are used to dynamically adjust the production-related process technical indicators, reduce the fluctuation of the ore grade entering the mill caused by the lack of a homogenization yard, the fluctuation of the dissolution rate caused by the inability to adjust the ore blending in time, and reduce the ore consumption and alkali consumption.

[0021] 2. The present invention can realize the analysis of various components in the ore. The online ore detection system can detect the "effective alumina" and "active silicon" indicators of the ore entering the mill in real time, and can pre-judge and pre-control the most critical and important technical indicator data of alumina. At the same time, according to the real-time measurement indicators, the addition of ore and mother liquor can be adjusted in time to improve production efficiency and system output. Under certain dissolution conditions, some minerals can react with alkaline solutions, while others cannot. Diaspore cannot be dissolved under trihydrate dissolution conditions and cannot be counted as effective aluminum. Therefore, understanding the physical phase is very critical, not the element.

[0022] 3. The present invention can realize the homogenization and intelligent ore blending of bauxite. The application of the ore online detection system can realize the pre-control of production ore blending, and the online detection of ore components can realize the local closed-loop control of ore blending and mother liquor addition. At the same time, combined with the existing ak measurement of dissolution, the loss can be reduced again by setting the target ak measurement range. Secondly, according to the changes in the effective alumina and reactive silicon of the ore, the dissolution ak value can be dynamically set and adjusted to improve the dissolution rate and system output.

[0023] 4. The present invention eliminates manual mining and processing work. After the ore online detection system is put into use, the measurement results meet the production requirements after the detection data comparison; the final production decision cancels the sampling and analysis work of the mill; reduces the labor intensity of personnel, reduces the workload, and eliminates the unsafe factors and human interference factors in the sampling process; eliminates the original sampling method that is time-consuming, labor-intensive, and has the hidden dangers of mechanical damage and dust inhalation; realizes automatic detection of bauxite materials entering the mill, and can start the equipment locally and remotely to meet the unmanned requirements; no manual intervention is required before, during, and after the start of the ore online detection system operation.

Brief Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the main process of the method described in the embodiment of the present invention;

[0025] Figure 2 A structural diagram of compressed air preparation for the pre-installation of an infrared spectrum online detection system according to an embodiment of the present invention;

[0026] Figure 3 This is the overall network architecture diagram of the online ore grade intelligent measurement system;

[0027] Figure 4 It is a partial flow chart of the method described in the embodiment of the present invention;

[0028] Figure 5 This is a comparison chart of the results after implementing the infrared spectrum online detection intelligent analysis system. [Specific implementation method]

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0030] This embodiment provides a method for online control of alumina slurry preparation of imported bauxite using infrared spectroscopy, and its process flow chart is as follows: Figure 1 As shown, the specific steps include:

[0031] Step 1: Transportation of bauxite;

[0032] The imported gibbsite-type bauxite is transported to the port by sea, unloaded by a ship unloader at the dock, and transported to the fully enclosed rectangular ore yard in the alumina plant through an ore conveyor belt, where it is stored using an elevated horizontal stacker. The bauxite in the yard is reclaimed by a bridge-type scraper reclaimer;

[0033] Step 2: bauxite blending;

[0034] Use unmanned stackers for intelligent ore blending, blending new ore with retained ore, blending high-grade alumina ore with low-grade alumina ore, and control the ore grade curve within ±0.5% as much as possible. The data volatility after implementing the infrared spectrum online detection intelligent analysis system is lower, which improves the accuracy and guidance of bauxite grade determination.

[0035] Step 3: Crushing of ore;

[0036] After being conveyed by the discharging belt conveyor, iron removed by the iron remover, screened by the cross screen, and crushed by the coarse and fine crushers (firstly, the coarse crusher is used to crush the bauxite to a fineness of less than 50mm, and then the fine crusher is used to crush the bauxite to a fineness of less than 15mm) to a size of less than 15mm that meets the grinding requirements, it is then transported to the grinding head bauxite bin;

[0037] Step 4: Infrared spectrum online detection intelligent analysis system for sampling and testing;

[0038] like Figure 1The figure shows the whole process involving the infrared spectrum online detection system. After crushing and before ball milling, infrared spectrum detection is introduced. The online detection system can detect 13 components such as Al2O3, SiO2, Fe2O3, CaO, K2O, Na2O, SO3, TiO2, attached water, total carbon, organic carbon, activated alumina, and reactive silicon.

[0039] Figure 2 Prepare the structural diagram of compressed air for the preliminary installation of the infrared spectrum online detection system. Figure 3 This is the overall network architecture diagram of the online ore grade intelligent measurement system.

[0040] Figure 2 In the early stage of the installation of the infrared spectrum online detection system, the compressed air preparation includes a vortex cooler for cooling the control cabinet, the vortex cooler is connected to a compressed air pistol, the compressed air pistol is connected to an adsorption dryer, the adsorption dryer is used to provide compressed air, the adsorption dryer is connected to a vortex cooler, the vortex cooler is used to cool the analyzer, and multiple manual valves are also set up, which can be opened and closed as needed, such as Figure 2 As shown in the figure, it is a device used for the preliminary preparation of compressed air. The role of compressed air is to be used for the daily maintenance and cleaning of infrared spectrum detection hardware equipment; the overall network framework of the infrared spectrum online detection system is shown in Figure 3 As shown, when in use, the laboratory XRF analysis method is used in the early stage to provide data support for the ore online detection analyzer, establish a model, and use the ore online detection to analyze the active alumina and reactive silica in the ore and the chemical composition to find the balance point of ore consumption and alkali consumption, so as to reduce the unit consumption of ore and alkali consumption. According to the content of active alumina and reactive silicon to guide the ore and alkali solution, it can significantly save the process alkali consumption index and improve the dissolution rate.

[0041] Step 5: grinding of slurry;

[0042] Based on the detection data of step four, the ore blending guidance is carried out for the ore discharged from the grinding head bin and the alkali blending guidance is carried out for the circulating mother liquor. The bauxite in the grinding head bin and the circulating mother liquor sent by evaporation enter the ball mill in a certain proportion.

[0043] The specific amount of the circulating mother solution added is calculated by referring to the following formula:

[0044] 1. Solid content (t / m 3 ) = solid content (g / l) / 1000*(1+reaction rate);

[0045] 2. Dry ore weight = ore quantity*(1-attached water);

[0046] 3. Dry ore volume = dry ore weight / ore specific gravity;

[0047] 4. Attached water volume = ore volume * attached water / 1;

[0048] 5. Mother liquor volume = dry ore weight / solid content (t / m 3 )-(dry ore volume + attached water volume);

[0049] 6. The amount of mother liquor entering the mill = the amount of ore discharged * 0.29;

[0050] 7. Mother liquor ratio = mother liquor volume / ore volume

[0051] The following table provides examples:

[0052]

[0053] It should be noted that the bauxite blending and alkali blending of circulating mother liquor is a dynamic process. As the data such as the amount of ore discharged changes, the data such as the amount of mother liquor will also change. It is a real-time dynamic adjustment process.

[0054] Next, the pulp produced by the ball mill is graded by the hydrocyclone, the underflow (coarse sand) of the hydrocyclone is returned to the mill for re-grinding, and the overflow (qualified pulp) flows to the rotary screen by gravity, and the light impurities are screened out by the rotary screen before entering the finished pulp tank; the final pulp fineness is: +60#: 6~16%; solid content: 400±20g / l. Finally, the qualified pulp is obtained, which reduces energy consumption and provides higher quality pulp for the subsequent dissolution process.

[0055] Effect verification:

[0056] In order to further illustrate the effect of the present application, the present application verifies the accuracy of the infrared spectrometer.

[0057] The committed standard deviation between the online system detection value and the laboratory sampling XRF analysis value meets the technical requirements, such as Figure 5 As shown, from Figure 5 It can be seen that the total aluminum, effective aluminum, silicon, iron content and other items of the two methods are all within the allowable difference range, indicating that the detection of bauxite ore composition shown in this application is accurate and effective.

[0058] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for online regulation of alumina slurry preparation from imported bauxite using infrared spectroscopy, characterized in that: The steps include: (1) Unloading the bauxite and sending it to the ore yard via a conveyor belt; (2) The bauxite is blended by an automatic stacker and reclaimer, and the iron is removed before crushing. The chemical composition of the bauxite is analyzed by infrared spectroscopy. The crushed material is transported to the grinding head bauxite bin via a discharging belt. The bauxite in the grinding head bauxite bin and the circulating mother liquor sent by evaporation are then sent to a ball mill, where they are ground into a slurry; (3) The slurry produced by the ball mill is classified by a cyclone. The coarse sand at the bottom of the cyclone is returned to the ball mill for further grinding. The overflow of the cyclone flows to the rotary screen by gravity. After the light impurities are screened out by the rotary screen, it enters the finished slurry tank to obtain qualified slurry.

2. The method according to claim 1, characterized in that The crushing in step (2) is performed by using a coarse crusher to crush the bauxite to a fineness of less than 50 mm, and a fine crusher to crush the bauxite to a fineness of less than 15 mm.

3. The method according to claim 1, characterized in that The bauxite in step (1) is imported gibbsite-type bauxite.

4. The method according to claim 1, characterized in that In the step (2), after crushing and before ball milling, an infrared spectrum online detection intelligent analysis system is introduced to detect the content of effective ingredients in the bauxite.

5. The method according to claim 4, characterized in that In step (2), the ratio of bauxite to the circulating mother liquor sent by evaporation is adjusted according to the content of effective components in the bauxite. The effective components include 13 components: Al2O3, SiO2, Fe2O3, CaO, K2O, Na2O, SO3, TiO2, attached water, total carbon, organic carbon, activated alumina, and reactive silicon.

6. The method according to claim 2, characterized in that The infrared spectrum detection performed in step (2) is achieved through an infrared spectrum online detection intelligent analysis system.

Images