Abstract
The present invention discloses a method of using high magnesium phosphorus tailings to produce light magnesium carbonate, including the following steps: calcining high magnesium phosphorus tailings into calcined white at high temperature, mixing calcined white and water with a certain proportion of digestion to obtain a digestive solution, supplementing a certain proportion of water in the digestive solution and then passing in a gas containing carbon dioxide for the carbonization reaction to obtain the carbonized liquid, the reaction stops after the carbonized liquid filtration to obtain the filtrate of heavy magnesium water, pyrolysis of heavy magnesium water to obtain a light magnesium carbonate precipitate, precipitate, after filtration, drying to obtain a light magnesium carbonate product. The heavy magnesium water is pyrolyzed to get light magnesium carbonate precipitate, and the precipitate is filtered and dried to get light magnesium carbonate products. This invention turns waste into treasure, recycle and utilize the magnesium resources in the waste high magnesium phosphorus tailings, the process is simple and low cost, the economic and environmental benefits are remarkable.
Description
A method of producing lightweight magnesium carbonate by utilizing high magnesium phosphorus tailings
Technical Field
The present invention relates to the field of chemical technology, specifically a method of producing lightweight magnesium carbonate by utilizing waste high magnesium phosphorus tailings.
Background technology
Since most of the phosphorus ores in China are medium and low grade phosphorus ores, they generally need to be beneficiated and enriched into commercial phosphorus concentrates by chemical flotation. High-magnesium phosphorus tailings are the by-products after phosphorus ore is enriched into phosphorus concentrate by flotation, with P2O5 content of 3%-8.5% and MgO content of 15%-21%, which belongs to high-magnesium low-grade phosphorus ore. For the annual output of 3 million tons of phosphorus concentrate processing plant, each year produces about 1 million tons of high magnesium phosphorus tailings, containing about 180,000 tons of MgO. For a long time, because of the tailings of low phosphorus content, the use of the pathway is less, is usually treated as a waste by the enterprise using the way of waste stockpiling for disposal, not only so that the magnesium resources in the tailings are wasted, but also occupy the land, pollution of the surrounding environment.
Light magnesium carbonate is an important inorganic chemical product, in addition to the preparation of magnesium oxide and magnesium salt series of products, mainly used as a good filler and reinforcing agent for rubber products, high-temperature fireproof thermal insulation materials, insulating materials, as well as used in shipbuilding, boiler manufacturing, coatings, inks, ceramics, glass, pharmaceuticals, daily-use chemical industry, a wide range of applications. The methods for producing lightweight magnesium carbonate mainly include magnesite ammonium carbonate method, dolomite carbonization method and brine soda ash method.
Content of the invention
The purpose of the present invention is to overcome the above shortcomings and provide a method of producing lightweight magnesium carbonate by utilizing high magnesium phosphorus tailings, which can recycle and utilize the magnesium resources in the high magnesium phosphorus tailings, and has the characteristics of low cost, simple process, and good quality of products.
In order to realize the above purpose, the present invention adopts the following technical solution: a method of producing lightweight magnesium carbonate by utilizing high magnesium phosphorus tailings, including the following steps:
(1) Calcining the high magnesium phosphorus tailings at 850 to 1180°C and burning them into calcined white;
(2) Mixing said calcined white with water at a weight ratio of 1:4 to 40, and stirring and digesting at a temperature of 20 to 90°C for 10 to 100 minutes to obtain a digestive solution;
(3) supplementing water in said digestive liquor so that the solids content of the digestive liquor is 2% to 15% by mass, and then passing a gas containing carbon dioxide into the digestive liquor to carry out a carbonization reaction at a temperature of 10 to 35 ℃ to obtain a carbonization liquid, stopping the reaction when the pH value of the carbonization liquid is reduced to 6.6 to 8.0, and filtering the carbonization liquid, the filtrate is heavy magnesium water, and the filter cake is mainly calcium carbonate.
(4) Pyrolyze said heavy magnesium water at 80~105°C for 0.2~3h to obtain light magnesium carbonate precipitation, filter to obtain light magnesium carbonate filter cake, and the filtrate water is reused in digestion and carbonization process.
(5) The said light magnesium carbonate filter cake is baked at 90～220℃ for 0.5～5h to get light magnesium carbonate product.
The above high magnesium phosphorus tailings are minerals containing low-grade phosphorus pentoxide discharged after obtaining high-grade phosphorus pentoxide phosphorus concentrates from phosphorus ores in the beneficiation process, containing P2O5 of 2% to 10%, MgO of 15% to 21%, and CaO of 28% to 42%.
The carbon dioxide-containing gas described above is a gas with a carbon dioxide volume fraction of 20% to 100%, and may be a carbon dioxide gas produced during the calcination of high magnesium phosphorus tailings.
The present invention has the following advantages:
1, the present invention takes industrial waste high magnesium phosphorus tailings as raw material, waste utilization, resource saving, low production cost, and broadens the range of raw materials for producing light magnesium carbonate.
2, the invention to high magnesium phosphorus tailings as raw materials, in addition to energy consumption, almost no need for other industrial raw materials involved in the production, the process is simple and magnesium recovery rate is high; This invention can be popularized and applied to a large number of high magnesium phosphorus tailings treatment for phosphate mining and mineral processing enterprises to deal with high magnesium phosphorus tailings provides an effective method.
3, the lightweight magnesium carbonate produced by this invention meets the relevant standards of industrial hydrated basic magnesium carbonate, and the product is of good quality.
4, the invention of the production process without pollution, in line with the requirements of cleaner production process, to solve the raw material of high magnesium phosphate tailings occupy land resources, pollution of the environment, turning waste into treasure, has good economic benefits and important environmental significance.
Specific implementation
In order to facilitate the understanding of the present invention, the following examples to illustrate the content of the present invention, the content of the present invention is not limited to the following examples.
Example 1
High magnesium phosphorus tailings chemical composition: P2O57.04%, MgO16.86%, CaO37.48%
Weigh 100g of tailed magnesium phosphorus tailings were calcined at 980°C to obtain calcined white 61.4g. Calcined white was stirred with 700g of water at 80°C for 40 minutes to obtain a digestive solution. Supplement 800g of water to the digestive solution, and then pass 35% carbon dioxide volume fraction of gas into the digestive solution at 20 ℃ for carbonization reaction to obtain the carbonization solution, stop the reaction when the pH value of the carbonization solution drops to 6.7, filter the carbonization solution, and the filtrate is heavy magnesium water. Said heavy magnesium water was pyrolyzed at 95°C for 0.5h to obtain light magnesium carbonate precipitation, filtered to obtain light magnesium carbonate filter cake, and the filter cake was baked at 150°C for 3h to obtain light magnesium carbonate product.
Example 2
High magnesium phosphorus tailings chemical composition: P2O56.00%, MgO18.25%, CaO36.82%
Weighing the tail magnesium phosphorus tailings 100g calcined at 950 ℃, get calcined white 59.8g, calcined white and 500g of water at 80 ℃ stirred for 30 minutes, to get the digestive solution. Supplement 600g of water to the digestive solution, and then pass 30% of carbon dioxide volume fraction of gas into the digestive solution to carry out carbonization reaction at 25 ℃ to obtain the carbonization solution, stop the reaction when the pH value of the carbonization solution drops to 6.9, filter the carbonization solution, and the filtrate is heavy magnesium water. Said heavy magnesium water was pyrolyzed at 93°C for 0.8h to obtain light magnesium carbonate precipitation, filtered to obtain light magnesium carbonate filter cake, and baked the filter cake at 180°C for 2h to obtain light magnesium carbonate product.
Example 3
High magnesium phosphorus tailing chemical composition: P2O56.35%, MgO18.59%, CaO37.01%
Weighing the tail magnesium phosphorus tailings 100g calcined at 960 ℃, get calcined white 60.5g, calcined white and 430g of water at 85 ℃ stirred for 30 minutes, to get the digestive solution. Supplement 900g of water to the digestive solution, and then pass 27% carbon dioxide volume fraction of gas into the digestive solution at 30 ℃ for carbonization reaction to obtain the carbonization solution, stop the reaction when the pH value of the carbonization solution drops to 6.8, filter the carbonization solution, and the filtrate is heavy magnesium water. Said heavy magnesium water was pyrolyzed at 97°C for 0.5h to obtain light magnesium carbonate precipitation, filtered to obtain light magnesium carbonate filter cake, and baked the filter cake at 120°C for 4h to obtain light magnesium carbonate product.
Example 4
High magnesium phosphorus tailings chemical composition: P2O59.84%, MgO15.03%, CaO41.79%
Weighing the tailed magnesium phosphorus tailings 100g calcined at 1180 ℃, obtaining calcined white 65.3g, calcined white and 262g of water stirred at 90 ℃ for 100 minutes, obtaining the digestive solution. Supplement 110g of water to the digestive solution, and then pass 20% carbon dioxide volume fraction of gas into the digestive solution to carry out a carbonization reaction at 10°C to obtain a carbonization solution, stop the reaction when the pH value of the carbonization solution is reduced to about 8.0, filter the carbonization solution, and the filtrate is heavy magnesium water. Said heavy magnesium water was pyrolyzed at 105°C for 0.2h to obtain light magnesium carbonate precipitation, filtered to obtain light magnesium carbonate filter cake, and baked the filter cake at 220°C for 0.5h to obtain light magnesium carbonate product.
Example 5
High magnesium phosphorus tailings chemical composition: P2O52.15%, MgO20.93%, CaO28.15%
Weighing the tailed magnesium phosphorus tailings 100g calcined at 850 ℃, obtaining calcined white 56.4g, calcined white and 2256g water stirred at 20 ℃ for 10 minutes, obtaining digestive solution. Supplement 508g of water to the digestive solution, and then pass 99% carbon dioxide volume fraction of gas into the digestive solution to carry out a carbonization reaction at 22°C to obtain a carbonization solution, stop the reaction when the pH value of the carbonization solution is reduced to about 6.6, and filter the carbonization solution, and the filtrate is heavy magnesium water. Said heavy magnesium water is pyrolyzed at 80°C for 3h to obtain light magnesium carbonate precipitation, filtered to obtain light magnesium carbonate filter cake, and the filter cake is baked at 90°C for 5h to obtain light magnesium carbonate product.