Four-hearth shaft kiln for dolomite calcination and dolomite calcining method thereof

Abstract

The invention provides a four-hearth shaft kiln for dolomite calcination and a dolomite calcination method thereof. A shaft kiln body comprises a kiln body shell and a refractory material. The shaft kiln body is provided with four kiln cylinders, the four kiln cylinders are encircled into a circle, and the four kiln cylinders are communicated with one another through connecting channels at the lower parts of respective calcination zones; a feeding bin is arranged in the center of the top of the shaft kiln body, a rotary distributing device and four feeding pipes are arranged at the bottom of the feeding bin, and the outlet ends of the four feeding pipes are located in the four kiln cylinders respectively. An exhaust cylinder, a compressed air nozzle and a fuel nozzle are further arranged at the top of each kiln cylinder; the bottom of each kiln cylinder is connected with a cooling fan, and a discharging mechanism is arranged at the bottommost portion of each kiln cylinder. According tothe four-hearth shaft kiln, kiln cylinder feeding and airflow reversing are controlled, heat is transferred to cold materials, the space utilization rate is high, the heat utilization rate is high, losses are small, calcination is uniform, the phenomena of overburning and underburning are avoided, the product quality is high, the investment cost is low, and the four-hearth shaft kiln is suitablefor large-scale industrial production and application.

Description

technical field [0001] The invention relates to a four-chamber vertical kiln for calcining dolomite and a method for calcining dolomite, belonging to the technical field of kiln calcining. Background technique [0002] In recent years, my country's annual primary magnesium production has exceeded 900,000 tons, accounting for more than 90% of the world's total primary magnesium production, and its dolomite consumption has exceeded 8 million tons. Calcination of raw material dolomite is a very important link in silicon thermal magnesium smelting, which determines the quality of calcined white and directly affects the reduction rate of magnesium. At present, the dolomite calcination equipment mainly includes rotary kiln and shaft furnace. Although the rotary kiln can meet the requirements of dolomite for various calcination conditions, the operating cost is high, the heat utilization rate is low, and it is easy to form rings. Maintenance Frequent disadvantages; the calcination...

AI Technical Summary

Problems solved by technology

At present, the dolomite calcination equipment mainly includes rotary kiln and shaft furnace. Although the rotary kiln can meet the requirements of dolomite for various calcination conditions, the operating cost is high, the heat utilization rate is low, and it is easy to form rings. Maintenance Frequent disadvantages: uneven calcination temperature in vertical kiln, low activity of calcined white, which greatly affects the output rate of magnesium in the reduction process

At present, the newly developed double-tube shaft kiln in dolomite calcination has shown great advantages, the heat utilization rate has been improved, and the calcined white activity is high, but there are still low output and a large amount of heat that has not been utilized and the loss needs to be further improved. Strengthen utilization, and directly discharge carbon dioxide, causing air pollution and greenhouse gas effects

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