SU872453A1 - Method of thermal treatment of phosphorus-containing raw material pellets - Google Patents

Description

(54) METHOD FOR THERMAL SHORT-TREATMENT OF COMPRESSED PHOSPHORUS CONTAINING. RAW MATERIALS The invention relates to thermal, preparation of raw materials on conveyor-type machines, such as phosphorite, for electrothermal processing to yellow phosphore and can be used in the chemical industry and metallurgy. A method of preparing phosphorite roes by the pelletizing method, in which finely ground ore fines of phosphate are mined, are known. and the obtained raw pellets are strengthened by heat treatment on roasting units l J The disadvantage of the known process is that the calcination of oats is carried out below those The temperature of the occurrence of a sufficient amount of fluid flow phases contributing to the hardening of the pellets during their cooling, therefore it is impossible to avoid destruction of the pellets during firing, the mechanical strength of the burned pellets is 80 kg / s, which contributes to the formation of a large number of returns. Also known is the method of heat treatment of pellets, in which TefMenature rezhami of all stations of thermal treatment of raw materials are proposed, which include drying at 2OO ° C for 20-23 minutes, drying at 1150-1200 ° C for min. Cooling. 1% 1And this is the strength of the phrases of the 1010-100 otsinakov in all technological zones in the O, V-O, 9 nm / s, Feed t @ ponosvte in the pro- duct layer. The strength of the pellets, which are heat-treated with 11SO-12OOC, is up to 15O kg / ca. To a decrease in the gas absorption and severity of the technical regime in noemeyio-, yschzhakh, UH-ZO-35%, the mechanical strength of the pellets of the lower goryoosh is increased. The goal of Iegretbiya is to raise pellets from the bottom of the 4th in the first year of the search for excursions in the first year of the search for excursions in the first year of the search for excursions in the first year, according to the method of thermal processing of the phosphorus-containing pellets, including drying and firing at the first, the first, the first, the former, the first, the first, in the process for 5-7% of the burning area, the coolant is fed on top of the layer in the amount of 1070, the second drying area, 4O-42% of the burning area, the coolant is fed from the bottom in the amount of 5t) -30O, and the rest of the area is heated The carrier is fed on top of the layer in the amount of 80-20 O m / m. The selected parameters for heating the area of the zones of the roasting mashine and the amount of heat exchanger provide heating of the top of the layer of ore to a depth of 20-5 O mm to the dew point and filtration rate O, 2-O, 5 m /with. The area of the first zone of the estate (5-7% of the total area of the mashina) ensures that the pellets stay in it for 1-2 minutes. When the heat carrier layer is less than 1 O m / m, the upper horizon of the pellets is slowly heated and its temperature is 20-50 mm deep. does not exceed the dew point {60-70 ° C), and when the amount of heat carrier is more than 7 m / m, moisture is released in the layer and condenses at a depth of mm, as a result of which excessive moisture occurs in the bed, leading to their destruction during further heat treatment. The second part of the drying area is intended to completely dry the plants. The flow of the 50-ZOO heat carrier is necessary to achieve a filtration rate through the layer of 1.2-1.6 m / s, which ensures removal of moisture of 0.65-0.85 m / ms If the amount of heat carrier is less than 5O, a vaI I concentration can occur in the middle horizon of an increase in the heat transfer rate above ZOO, the speed of the substance exceeds the critical parameters, which leads to the formation of microcracks and reduced pellet strength. . G Supply of heat transfer fluid less than 8O m / m to the burning zone does not allow achieving the minimum required burning rate, and an excess of 200 m / m causes intensive gas evolution during decarbonization and destruction of the coatings. PRI me R 1. The bed of the bed (burned pellets at 115 ° -1180 ° C) with a height of 5 mm in the amount of 5 kg is loaded onto a roasting bowl of a diameter of 400 mm and a height of 550 mm, and then a layer of raw pellets with a height of 300 mm in the amount of, f 35 kg. Humidity of the pellets 10.0-10.5%. Above the layer, the forge is ignited. As a heat carrier, the product of burning natural gas is used with a coefficient of air excess of 1.15, the temperature of the day of the burning of 1 products of combustion is set, and the discharge of BO mm of water under the layer. Art. After heating for 15 minutes, the upper layer is heated to a depth of 35 mm up to 80 C. The filtration rate is 0.35 nm MIND v After the layer is followed by sampling for moisture content, no over-wetting is found in the layer. temperature of 23СгС from the bottom of the layer for 14 minutes at the rate of 150 m / / m of the grid area During this time, at the indicated parameters, the layer of raw pellets dries out completely and does not accumulate damaged pellets and cracks. Then, the temperature in the furnace is raised to 12OO C, changing the direction of the heat transfer medium over the top and its suction in an amount of 120 m area for 18 minutes. After that, the "pellets" are cooled by filtering cold air and determine their mechanical strength as the average by determining the strength of the lower, middle and upper layers of the layer. The temperature distribution along the layer height is as follows: top. layer 1110 C, sulfur layer below the layer of 1040. The results of the study are shown in the table.

Waterlogging,% (increased moisture

beyond the original)

The number of pellets having after firing Cracks on the surface,%

The content of trivia,% (fraction 5-10 mm)

after unloading

2-4 2-3

Strength is fired nl1X okapney at

compression, kg / ok

Shock strength,% (fraction content

+5 mm after use in standard

drum).

Abrasion resistance,% (content

fractions - 0.5 mm after being tested

Claims (2)

standard drum) The technical and economic effect for the two technological lines of the phosphorus industry is more than 1 million rubles. per year. The claim of the method of heat treatment of phosphates containing phosphate raw materials, including drying and firing at 115О-12ОО С on the grate roasting grid, characterized in that, in order to increase the strength of the pellets and reduce the fines, the first drying zone is 5- 7% of the firing area, coolant at 872453 in the spreadsheet ZOO-32O 9O-95 3O-70m / / m is put on top of the layer, in the second drying zone, constituting 4O-42% of the firing area, coolant is fed to the BOTTOM of the layer in the amount of 5О-. . 300 m / m, and the rest of the area of the heat carrier is served on top of the layer in the amount of 8О-2ОО Sources of information taken into account during the examination 1. Research in the field of chemical electrothermia. Works LenNIIGiprohim. issue 1, 1967, p. 8-23. 2. Phosphorus industry, 1975, No. 16, p .. 4-11.