Method and device for producing calcium magnesium phosphate fertilizer from magnesium-removed clear liquid

Abstract

The invention discloses a method and a device for producing a calcium magnesium phosphate fertilizer from magnesium-removed clear liquid, and belongs to the technical field of wet-process phosphoric acid. The device comprises a primary clear liquid tank, an acidification reaction tank, an acidification liquid storage tank, a ball mill, an ore pulp tank, a magnesium removal reaction tank, a primary thickening tank, a repulping tank, a secondary thickening tank, a concentrate pulp storage tank, a return water neutralization reaction tank, a clear liquid neutralization reaction tank, a clarifying tank, a filter press and a calcium magnesium phosphate fertilizer production structure; a clear liquid outlet of the primary thickening tank is connected with the primary clear liquid tank; the primary clear liquid tank, the acidification reaction tank, the acidification liquid storage tank and the magnesium removal reaction tank are connected in sequence; the ball mill and the repulping tank are connected with the return water neutralization reaction tank, the primary clear liquid tank is also connected with the clear liquid neutralization reaction tank, and the clear liquid neutralization reaction tank is connected with the clarifying tank; a clear liquid outlet of the clarifying tank is connected with the return water neutralization reaction tank, and a sediment outlet of the clarifying tank is connected with the filter press; and a filter residue outlet of the filter press is connected with the calcium magnesium phosphate fertilizer production structure, and a filtrate outlet of the filter press is connected with the return water neutralization reaction tank.

Description

technical field [0001] The invention belongs to the technical field of wet-process phosphoric acid, and in particular relates to a method and a device for producing calcium-magnesium phosphate fertilizer from magnesium-removed clear liquid. Background technique [0002] Phosphorus is an essential element for crops. With the development of science and technology, the use of phosphorus is also expanding. Phosphate rock resources are important basic raw materials for the development of phosphorus chemical industry. The main mineral components of phosphorite rock are collophosite and microcrystalline apatite, and the secondary minerals are quartz, dolomite, calcite, feldspar clasts, and carbon argillaceous matter. And a small amount of sea green stone and so on. Phosphate rock is mainly used to make phosphoric acid, which plays a great role in the development of the national economy as a final chemical product or an intermediate product of other phosphorus chemical products. ...

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Problems solved by technology

[0003] like figure 1 As shown, it is the existing phosphate rock slurry treatment process, the primary clear liquid (pH is around 3.5, P 2 o 5 content of 1.1%, MgO content of 1.5-2.0%), part of it is used as the raw material of demagnesizing agent for reuse, and the other part is sent to the phosphogypsum re-slurry tank to the phosphogypsum storage yard (separating the backwater of phosphogypsum), and after long-term enrichment, it will increase The magnesium content in the backwater is high, and the backwater contains high magnesium, which will have a certain impact on the quality of downstream products after reuse (after a certain number of phosphogypsum backwater cycles, the content of magnesium oxide is greater than 0.9%), and it also causes a waste of magnesium resources.

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