Mineral separation method for separating calcium and magnesium in medium-low-grade phosphorite, urea ammonium nitrate calcium-magnesium fertilizer and ammonium magnesium sulfate nitrate fertilizer

Abstract

The invention provides a mineral separation method for separating calcium and magnesium in medium-low-grade phosphorite, a urea ammonium nitrate calcium-magnesium fertilizer and an ammonium magnesiumsulfate nitrate fertilizer, and relates to the technical field of mineral separation. The mineral separation method comprises the following steps: sequentially carrying out crushing, calcining, digesting, leaching decalcification and leaching magnesium removing on medium-low-grade phosphorite, wherein the decalcified filtrate obtained by leaching decalcification separation is subjected to concentration and synthesis to prepare a urea ammonium nitrate calcium-magnesium fertilizer, and / or the magnesium-removed filtrate obtained by leaching magnesium removing separation is subjected to concentration and granulation to obtain an ammonium magnesium sulfate nitrate fertilizer. The low-magnesium phosphate concentrate produced through the mineral separation method can meet the requirement for producing a nitrophosphate fertilizer with a low nitrogen-phosphorus ratio while a full-water-soluble urea calcium magnesium ammonium nitrate fertilizer and / or a magnesium ammonium sulfate fertilizer are / is produced as a byproduct, so that phosphorus, calcium and magnesium elements in medium-low-grade phosphorite are recycled.

Description

technical field [0001] The invention relates to the technical field of mineral processing, in particular to a mineral processing method for separating calcium and magnesium from medium and low-grade phosphate rocks, urea ammonium nitrate calcium magnesium fertilizer and ammonium sulfate nitrate magnesium fertilizer. Background technique [0002] my country's phosphate rock reserves rank second in the world, but compared with the world, there is a big gap in ore quality, selectivity, and phosphate rock mining. The basic reserves of phosphate rock that can be processed and utilized are relatively small. Low, only 4.054 billion tons, with many low-grade ores, its P 2 o 5 The rich ore with a mass fraction greater than 30% is only 1.108 billion tons, and China's phosphate rock P 2 o 5 The average mass fraction is about 17%. Most of the phosphate rock must be enriched to meet the production requirements of phosphoric acid and high-concentration phosphate fertilizer. According to...

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Problems solved by technology

Limited by technical and economic indicators, the grade of phosphorous concentrate obtained by reverse flotation is 30%~34%P 2 o 5 , MgO0.8~1.5%, to obtain higher grade phosphorus concentrate means the reduction of phosphorus yield and the increase of cost

Generally speaking, for the selected grade 20-28%P 2 o 5 The phosphorus recovery rate of calcium (magnesium) phosphate rock is between 90% and 96% by primary reverse flotation or secondary reverse flotation, and the beneficiation cost is 60-150 yuan / ton (based on 32%P 2 o 5 Phosphate concentrate); 0.3 to 0.7 tons of tailings are discharged after beneficiation, and the tailings containing P are discharged after a reverse flotation 2 o 5 ≤12%, MgO≥10%; tailings containing P after secondary reverse flotation 2 o 5 ≤10%, MgO≥15%; the magnesium content of the phosphate concentrate obtained by reverse flotation can be reduced to 0.8-1.5%, which can meet the requirements of phosphate rock for wet processing in most cases, but for the production of water-soluble Fertilizer and polyphosphoric acid, ammonium polyphosphate and other varieties and high tower melt granulation process, the magnesium content is still too high

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