Chinalco Shanxi Branch Technology Process Optimization

In 2014, it was the second year for China Aluminum Corporation in Shanxi to realize its three-year objective to get rid of difficulties, and it was an extremely crucial year for success. The first alumina plant, which is the main production unit of the Shanxi branch, is the main unit realized by the Shanxi branch. The company's technical management staff and technical backbones focus on process optimization and process potential while maintaining a steady daily production operation. Tap potential and technical innovation. In the past year, the plant has successively renewed and reconstructed more than 10 technological processes such as caustic washing system, air supply system, material flow, water system, and waste heat utilization, and realized simultaneous improvement of energy saving, creation efficiency, and process optimization. In 2015, Shanxi Branch provided support for increasing production and reducing consumption.

Alkali wash system process optimization. It is mainly to further streamline the caustic washing process and reduce the impact of caustic alkali on production indicators. In the past, the caustic washing of lye after the caustic solution in the sinter system was directly discharged into the crude liquid system, which caused the crude ak technical indicator to seriously exceed the standard for a short period of time. This not only affected the stability of the se ak indicator, but also caused destruction of the decomposition system. Even affect product quality; Alkaline washing after the Bayer process system is brought into the red mud filtration process, into the last washing and sedimentation system, affecting the washing effect, reducing the efficiency of the red mud filter, while affecting the Bayer red mud to the sintering method System ingredients.

After the optimization process, the alkaline solution after the alkaline washing of the two major systems is directly sent to the evaporation after precipitation, completely straightening out the whereabouts of the cleaning alkali liquor. After the transformation, Bayer's system index has been greatly improved, semen ak from 1.52 to 1.51, product quality has also been significantly improved in the fourth quarter, to achieve both the conservation of resources and improve the quality of the two good results.

Supply system reform. After more than one month of careful investigation and in-depth study, the plant has successively optimized and optimized many processes such as evaporating and pressurizing the acid process, firing kiln, and settlement. Reforming the process of evaporating and pressurizing high-pressure air to improve the grade of air ducts, re-laying of individual air ducts, and the need to add air compressors to each pickling operation has become history, which has effectively saved wind resources. According to calculations, only this one, each pickling can save more than 4,000 yuan in electricity; the burning kiln and settling wind, after a thorough investigation and scientific demonstration, replaced a more scientific pipe diameter, length, effectively improve the wind Pressure and wind efficiency. Settlement system, because the wind used in the washing process, is the end of the wind system, the air compressor no matter how much power consumption to mention the amount of air, the effect is not ideal, after research, the plant to cut off the washing wind, and the use of small air pressure Instead of high-pressure air, the machine not only solves the problem of wind cleaning in the process, but also effectively reduces power consumption and wind consumption. It also uses the wind in the high-temperature energy saving of the roasting system to block and replace part of the wind area. Effectively improve the utilization of wind.

Material flow optimization. The entire process of alumina production is a process of material flow. The potential of energy saving and consumption reduction is in the flow of materials. The potential for efficiency improvement is also in the flow of materials. Dozens of processes and more than one hundred sizes are in the flow of materials. get on.

The plant takes material flow optimization as the top priority in overall process optimization. In the past year, several processes including purification of filter cakes, improvement of diluted tanks, dissolution of waste water from sedimentation to washing, and washing of red mud, filtration of filtrates from washing to washing, and washing have been completed. The system indicators fluctuate. According to statistics, only the refinement of the process flow reform will increase the system concentration by 2~3g/l, and save 260,000 yuan of steam per month.

Two sets of vacuum pumps for the five evaporations are used for mutual backup, which effectively improves the problem of low evaporation vacuum degree; the 4# pan from roasting is changed from one wash to two washings; the raw material grinding amount is strictly measured by the inverse push method, and the synchronization The dosing chute is heightened to solve the problem of poor flowability of the raw slurry. The proportion of ingredients is revised to guide the raw materials to be milled to be more scientific and effectively solve the influence of unfavorable factors such as high moisture content of raw slurry and low C/S. It has laid a solid foundation for reducing clinker coal consumption and improving the clinker net dissolution, etc.; it has implemented the special project transformation for the problem of restricting the production process by using the coarse-fluid return flow of sintering process, after several months of research, construction, and trial operation, After optimization, the concentration of crude liquor in the sintering process was increased by 10~20g/l, which not only alleviated the problem of crude liquid confluence after the sintering process was increased, but also made active efforts to increase the semen concentration of the new and old systems and reduce the loss. Only this one can reduce the steam consumption by more than 4,000 tons, and can save more than 3 million yuan annually; the optimization of the process of adding cyclone and mother liquor reduces the liquid-solid ratio of the cyclone, and makes the cyclone better classify. Effectively improve the grading effect of the cyclone, and play a positive role in the next step to improve the product particle size; in order to meet the requirements of high-yield, the heightening of the overflow edge of the sedimentation tank has been pioneered, and the settlement time and settlement effect have been effectively improved, which is dissolution. High feed rates provide protection.

Water system optimization. The plant completed the transformation of evaporation cycle water into refined hot water tanks. Through the lack of steam heat exchange with the desiliconization tank, the circulating water is increased by 30°C, which greatly saves steam consumption; and the baking of the fluidized bed cooling water to the hot pan is completed. The process of transformation; completed the rapid separation of water processes and other aspects of transformation, to achieve a multi-process optimization of the water system at the same time, effectively saving water resources, improve water resources utilization.

Waste heat utilization process optimization. The plant has completed the transformation of the new evaporative forced effect process. After the flash evaporation of the dissolved EDP, the new evaporative liquid is heated and the liquid volume of about 100 m3 per hour can be increased by 20° C., which has played a positive role in reducing the steam consumption. More than 600,000 yuan; completed the rapid separation of steam, replacing the new steam reform, greatly reduced the steam consumption, and set a new record low in September 2014; completed the renovation of the office building heating from the new steam heating back to the process water warming, The monthly steam consumption can be reduced by about 1,000 tons, and the cost can be saved by more than RMB 80,000; the heating process of the clinker kiln cooling machine for the sinter process lotion is completed, and the transformation is mainly carried out using a partial sintering method as the clinker cooling machine. Drenched water, instead of the existing circulating water, is estimated to increase the concentration of the wash solution by about 5g/l; the dissolution of the dissolved EDS exhaust gas is completed through a wide plate heating and evaporation process, and the dissolved EDS hot water is used to heat and evaporate the original solution. The hour can be about 200m3 of evaporation liquid increased by 15 °C or more, 300m3 stock can be increased by about 20 °C, is expected to create 1.8 million yuan effect. These steam flow optimization measures all provide good technical conditions for reducing steam consumption and support the economic production and long-term development of the Shanxi branch.