阅读说明：本技术 一种从脱磷钢渣中分离磷和制备磷肥的方法 (A method of separation of phosphorus and phosphate fertilizer is prepared from dephosphorization steel slag ) 是由 杜传明 袁磊 于景坤 于 2019-09-26 设计创作，主要内容包括：本发明属于冶金资源再利用技术领域,具体涉及一种从脱磷钢渣中分离磷和制备磷肥的方法,首先将脱磷钢渣在熔融状态下进行氧化处理,冷却后对其进行破碎研磨。然后将脱磷钢渣在水溶液中进行选择性浸出,控制矿浆的pH值为3.0～4.5,使脱磷钢渣中富磷的固溶体相溶解并分离,反应后得到低磷残渣和含磷浸出液。再通过向含磷浸出液中添加碱性物质,升高浸出液的pH值,使浸出液中的磷形成磷酸钙盐沉淀。分离后的磷酸钙盐沉淀可直接作为磷肥使用,低磷残渣则在烧结或炼钢中使用。本发明能高效低成本地分离脱磷钢渣中的磷,进而制备了磷肥。脱磷钢渣中超过92％的磷以磷肥的形式被回收,同时残渣在钢铁冶金中再利用,实现了脱磷钢渣的资源化利用。(The invention belongs to Metallurgical resources reutilization technology fields, and in particular to a method of separation of phosphorus and phosphate fertilizer is prepared from dephosphorization steel slag, first dephosphorization steel slag is subjected to oxidation processes in the molten state, crushing grinding is carried out to it after cooling.Then dephosphorization steel slag is subjected to Selectively leaching in aqueous solution, the pH value for controlling ore pulp is 3.0~4.5, so that the solid solution phase of rich phosphorus in dephosphorization steel slag is dissolved and is separated, low-phosphorous residue and phosphorous leachate are obtained after reaction.Again by adding alkaline matter into phosphorous leachate, the pH value of leachate is increased, the phosphorus in leachate is made to form synthos precipitating.Synthos precipitating after separation can be used directly as phosphate fertilizer, and low-phosphorous residue then uses in sintering or steel-making.The phosphorus in dephosphorization steel slag is separated to energy high efficiency, low cost of the present invention, and then is prepared for phosphate fertilizer.It is more than that 92% phosphorus is recovered in the form of phosphate fertilizer, while residue recycles in Ferrous Metallurgy, realizes the resource utilization of dephosphorization steel slag in dephosphorization steel slag.)

1. a kind of separation of phosphorus from dephosphorization steel slag and the method for preparing phosphate fertilizer, characterized by the following steps:

(1) dephosphorization steel slag carries out oxidation processes in the molten state first, makes the mass fraction of FeO in steel slag lower than 8%, slowly After cooling, crushing grinding is carried out to dephosphorization steel slag；

(2) the resulting dephosphorization steel slag of step (1) is mixed with aqueous solution and carries out Selectively leaching；During Selectively leaching, PH value using hydrochloric acid and/or nitric acid solution control ore pulp is 3.0~4.5, after reaction, isolated low-phosphorous residue and phosphorous leaching Liquid out, low-phosphorous residue use in Ferrous Metallurgy；

(3) alkaline matter is added into the resulting phosphorous leachate of step (2), increases the pH value of leachate, until having a large amount of White precipitate generates, and the precipitating after separation mainly contains synthos, can use directly as phosphate fertilizer.

2. the separation of phosphorus according to claim 1 from dephosphorization steel slag and the method for preparing phosphate fertilizer, it is characterised in that: the step Suddenly in (1) during Slow cooling, when steel slag is cooled to 1100 DEG C from molten condition, control cooling velocity is lower than 10 DEG C/min.

3. the separation of phosphorus according to claim 1 from dephosphorization steel slag and the method for preparing phosphate fertilizer, it is characterised in that: the step Suddenly in (1) after crushing grinding, the granularity of dephosphorization steel slag is less than 0.1mm.

4. the separation of phosphorus according to claim 1 from dephosphorization steel slag and the method for preparing phosphate fertilizer, it is characterised in that: the step Suddenly in (2) during Selectively leaching, mechanical stirring is carried out to ore pulp.

5. the separation of phosphorus according to claim 1 from dephosphorization steel slag and the method for preparing phosphate fertilizer, it is characterised in that: the step Suddenly the alkaline matter added in (3) is calcium hydroxide and/or sodium hydroxide.

6. the separation of phosphorus according to claim 1 from dephosphorization steel slag and the method for preparing phosphate fertilizer, it is characterised in that: the step Suddenly in (3) after addition alkaline matter, the pH value of leachate is increased to 7.5~9.0.

7. the separation of phosphorus according to claim 1 from dephosphorization steel slag and the method for preparing phosphate fertilizer, it is characterised in that: the step Suddenly gravitational settling and/or centrifuge separation are utilized in (3), separation and Extraction precipitates from leachate.

Technical field

The invention belongs to Metallurgical resources reutilization technology fields, and in particular to a kind of separation of phosphorus and preparation from dephosphorization steel slag The method of phosphate fertilizer.

Background technique

The steel production capacity in China is huge, and nearly 100,000,000 tons of the steel slag total amount generated every year.Because of the physico-chemical property and technology of steel slag Limitation, the slag comprehensive utilization rate in China are lower.Currently, main slag processing mode be by molten steel slag it is cooling broken after, It carries out magnetic separation and separates slag steel, remaining tailings is for construction material, road engineering or directly accumulation.These are not filled using method The potential value of steel slag is waved in distribution, causes the huge wasting of resources and environmental pollution.Therefore, how efficiently resource utilization Steel slag is iron and steel enterprise's project urgently to be resolved.

As steel require phosphorus content the raising of phosphorus content in increasingly strict and iron ore, many steel mills are in steelmaking process In use dephosphorization of molten iron technique.This technique has divided traditional steel-making function, reduces molten iron as much as possible before molten steel decarburization Middle phosphorus content, and generate dephosphorization steel slag.Since the molten iron after dephosphorization contains only a small amount of phosphorus, converter decarbonizing process can be in few slag situation It is lower quickly to carry out, and the decarburization steel slag generated can return to dephosphorizing process as flux.This not only reduces steel slag yield, improve Production efficiency, and make it possible the smelting of high phosphorus hot metal.

Currently, the dephosphorization technology of mainstream includes converter duplex method and converter double slag process (MURC).Converter duplex method is to use Two converters, carry out dephosphorization treatment to molten iron first in first converter, and the molten iron after dephosphorization pours into second converter and carries out Carbonization treatment.Converter double slag process refers to that dephosphorization and decarburization carry out respectively in same converter, first progress dephosphorization treatment, by dephosphorization After steel slag discharge, retain molten iron and continue carbonization treatment, then pour out molten steel, retains decarburization steel slag for next furnace molten iron Dephosphorization.

Due to the recycling of decarburization steel slag, dephosphorization steel slag is mainly discharged using the steelmaking process of dephosphorization of molten iron technique.With Traditional steel slag is compared, and dephosphorization steel slag has lower basicity (CaO and SiO₂Mass fraction ratio be 1.2~2.2), and contain 2~10% P₂O₅.Although the phosphorus content in dephosphorization steel slag is lower compared with rock phosphate in powder, since China generates a large amount of steel every year Slag, the storage total amount of phosphorus is huge in steel slag.Therefore, dephosphorization steel slag is a kind of potential phosphor resource.If in dephosphorization steel slag Phosphorus can be used for producing phosphate fertilizer by separation and Extraction, and the steel slag after dephosphorization can be used as flux for metallurgy and be recycled in steel mill, Realize the resource utilization of steel slag.The extraction of phosphorus has the development of steel and iron industry and phosphate industry great in dephosphorization steel slag Meaning.

Mineral facies in dephosphorization steel slag are mainly the solid solution phase (2CaOSiO that dicalcium silicate and tricalcium phosphate are formed₂– 3CaO·P₂O₅), magnesium wollastonite phase (3CaOMgO2SiO₂), matrix phase (CaO-SiO₂–Fe_t) and Zeylanite phase O (Fe_tO–MgO–MnO).P elements distribution ratio with higher between solid solution phase and other mineral facies, illustrates that phosphorus is mainly rich Collection is in solid solution phase.Therefore, in dephosphorization steel slag the separation of phosphorus depend primarily on rich phosphorus solid solution phase and other mineral facies Separation.

According to the difference of physicochemical properties between mineral facies each in steel slag, many steel slag dephosphorizing technologies are just studied to be opened Hair.Through patent retrieval, mainly there is technical solution below: the recycling of Chinese patent<phosphorus element from converter duplex dephosphorized slag>, Shen Please number be 201010171945.1, develop it is a kind of using magnetic separation technology by phosphorus non-magnetic phase rich in dephosphorization steel slag and rich ferromagnetism Mutually it is separately recovered；Chinese patent<a kind of steel slag recoverying and utilizing method>, application No. is 201410352003.1, develops a kind of benefit With the processing method being recycled after rich phosphorus solid solution in floatation process removing steel slag；Japan Patent < steel processed ス ラ グ か ら Iron and び Phosphorus recovery method >, Publication No. JP2014-1456A develops a kind of reduced steel slag and obtains the side of ferrophosphor(us) Then method obtains high phosphorus slag to alloy dephosphorization again, as phosphor resource.These patented technologies have processing cost high, and dephosphorization is imitated The disadvantages of rate is low, and isolated phosphorus is underused, therefore also non-large-scale application is in actual production.

Solid solution phase (the 2CaOSiO of rich phosphorus in dephosphorization steel slag₂–3CaO·P₂O₅) solubility with higher in water, And other iron-containing mineral phase solubilities are lower, therefore can separate the phosphorus in dephosphorization steel slag using the method leached.The present invention People is at paper " ISIJ International ", Vol.58 (2018), proposes this method and work in No.5, pp.833-841 Skill: dephosphorization steel slag being leached in aqueous solution, dissolves solid solution phase individually, and matrix phase and iron magnesium phase are then retained in steel Phosphorous leachate is obtained in slag, after leaching.Japan Patent < high concentration To Phosphorus The takes off Phosphorus ス ラ グ か ら Phosphorus containing む and separates back Receiving method >, Publication No. JP2019-26865A leaches the high phosphorus slag after modification using this method, separates and recycle Phosphorus in steel slag, the overall recovery of phosphorus are more than 70%.A kind of Chinese patent <biomass lime-ash modification converter slag dephosphorization circulation >, application No. is 201811183045.1, develops a kind of pair of steel slag and carry out modifying process, then obtain liquid fertilizer using leaching Expect, the dissolution rate of phosphorus reaches 90% in steel slag, but about 10% iron dissolves out simultaneously.Above two patented technologies have used price Expensive citric acid solution, and need to add modification agent to steel slag modification, lead to complex process, production cost is high.

The above-mentioned each patented method of comprehensive analysis, leaching-out technique are a kind of effective ways that phosphorus is recycled from dephosphorization steel slag, But the technique developed at present haves the defects that different, and practicability is low, it is difficult to industrial applications.

Summary of the invention

In order to solve the above technical problems, the present invention provides a kind of from dephosphorization steel slag separation of phosphorus and the side for preparing phosphate fertilizer Method, in view of the above shortcomings of the prior art, the technical problems to be solved by the present invention are: providing a kind of high efficiency, low cost, suitable The phosphorus in dephosphorization steel slag is leached and separated for industrial production, energy effective selectivity, further prepares the method for phosphate fertilizer；Make simultaneously Dephosphorization steel slag after dephosphorization recycles in iron and steel enterprise as a kind of flux for metallurgy, realizes the resource utilization of steel slag, exploitation Out in steel slag each component potential value.Dephosphorization steel slag carries out oxidation processes under high temperature fused state first in the present invention, makes The mass fraction of FeO is lower than 8% in steel slag.After dephosphorization steel slag Slow cooling, crushing grinding is carried out to it.Later, by dephosphorization steel Slag and aqueous solution are mixed to get ore pulp and carry out Selectively leaching.During Selectively leaching, hydrochloric acid and/or nitric acid solution are utilized The pH value for controlling ore pulp is 3.0~4.5.After reaction, isolated low-phosphorous residue and phosphorous leachate.Low-phosphorous residue mainly contains Iron, calcium and manganese can recycle in Ferrous Metallurgy.By adding alkaline matter into phosphorous leachate, the pH of leachate is increased Value, until there is a large amount of white precipitate to generate.Precipitating after separation mainly contains synthos, can use directly as phosphate fertilizer.

(1) in steelmaking process, the dephosphorization steel slag after dephosphorization is poured into slag ladle, then the steel slag of high-temperature fusion is blown rapidly Oxygen or air carry out oxidation processes, metallic iron and FeO in dephosphorization steel slag are made quickly to be oxidized into Fe₂O₃.This is because Research " Journal of Sustainable Metallurgy " before, Vol.4 (2018) are sent out in No.4, pp.443-454 It is existing, when there are when a large amount of FeO, the dissolution rate of phosphorus is lower in steel slag when leaching and the dissolution rate of iron is higher, unfavorable in dephosphorization steel slag In Selectively leaching.In addition, being difficult to prepare the phosphate fertilizer of high-quality using the leachate rich in iron ion.To realize ideal selection Property leach and prepare phosphate fertilizer, the oxidation processes of steel slag are necessary.Because steelmaking process is also oxidation reaction, at the oxidation of steel slag Reason can be carried out using existing equipment, without adding extras.When oxidation processes, the oxidation reaction of FeO is exothermic reaction, institute It is not necessarily to heat source with this process, has saved mass energy.P elements will do it reallocation in the dephosphorization steel slag oxidation process of melting And enrichment.After oxidation processes, make the mass fraction of FeO in dephosphorization steel slag lower than 8%.

(2) after oxidation processes, by the dephosphorization steel slag Slow cooling of melting, and cooling velocity is controlled, promotes to be dissolved in steel slag The enrichment of body and crystal grain are grown up, while iron-containing mineral facies being made to crystallize precipitation from liquid slag.When temperature is lower than 1100 DEG C, steel The composition of each mineral facies and metamorphosis very little in slag.Therefore, when steel slag is cooled to 1100 DEG C from molten condition, control cooling Speed is lower than 10 DEG C/min.Dephosphorization steel slag after cooling is subjected to multiple stage crushing and grinding by crusher and ball mill, makes steel The granularity of slag is less than 0.1mm, and the solid solution phase convenient for phosphorus rich in steel slag sufficiently exposes, and increases its surface area, promotes solid solution phase Dissolution separation in leaching process.

(3) dephosphorization steel slag obtained in step (2) and aqueous solution are mixed to get ore pulp and carry out Selectively leaching, simultaneously Mechanical stirring is carried out to ore pulp, accelerates reacting between steel slag particle and aqueous solution, improves the dynamic conditions of phosphorus dissolution, is improved Reaction efficiency.Due to the solid solution phase (2CaOSiO of rich phosphorus₂–3CaO·P₂O₅) soluble easily in water, it may occur that reaction is as follows:Lead to the pH value liter of ore pulp It is high.When the pH value of ore pulp is excessively high, precipitation reaction can occur for the phosphate anion of dissolution, produce calcium phosphate precipitation.Therefore, it is selecting The pH value that acid solution adjusts control ore pulp is added in selecting property leaching process, on the one hand promote the decomposition of solid solution, on the other hand Inhibit the precipitating of phosphate anion.The present invention has selected cheap hydrochloric acid and/or nitric acid as the acid solution of addition.Work as mine When the pH value of slurry is too low, in addition to the solid solution phase of rich phosphorus in steel slag, other iron-containing mineral facies can also dissolve simultaneously, cause to leach The increase of iron concentration in liquid, is degrading Selectively leaching, is also unfavorable for extracting phosphate fertilizer from leachate.Optimizing research shows The pH value of ore pulp, which should be controlled, is just able to achieve ideal Selectively leaching 3.0~4.5.It is isolated low by filtering after reaction Phosphorus residue and phosphorous leachate.Due to the separated and dissolved of solid solution phase, low-phosphorous residue mainly by iron-containing Zeylanite phase and Matrix phase composition.Iron, calcium, manganese element in residue are required components in steel-making, therefore low-phosphorous residue can be used as flux for metallurgy It is used in sintering or steel-making.

(4) the phosphorous leachate that step (3) obtains mainly contains calcium ion, silicate ion and phosphate anion, and iron, The concentration of manganese plasma is extremely low.It, can be by generating phosphorus because the solubility of synthos is very low in neutral or alkaline solution The mode of sour calcium precipitate recycles phosphorus from leachate.Present invention employs the addition basic species such as calcium hydroxide and/or sodium hydroxide The method of matter increases the pH value of leachate.Calcium ion and phosphate anion with the raising of pH of leaching solution, in leachate Form calcium phosphate precipitation.When pH value is excessively high, phosphate anion and silicate ion all form precipitating, lead to isolated phosphorus Silicone content is excessively high in hydrochlorate product and phosphorus content is lower, is not suitable as phosphate fertilizer.Optimizing research shows the pH when adjustment leachate When value is 7.5~9.0, there is a large amount of white precipitate to generate in leachate, most phosphate anion precipitating, and silicate from The rate of deposition of son is lower.The leachate for generating precipitating is stood, separates precipitating with solution.For further precipitation and separation, can adopt Use centrifugal separation technology.Then, precipitating is dried to obtain phosphate product.P in the product₂O₅Mass fraction be more than 35%, it is more Phosphorus in 97% has solubility in citric acid, and silicone content is lower.Because the main composition of phosphate fertilizer is calcium phosphate, the present invention is obtained Phosphate product can be used directly as phosphate fertilizer.After extracting phosphate in phosphorous leachate, low-phosphorous leachate can return to step Suddenly it is recycled in (3), reduces the consumption of water.

Specific technical solution is as follows:

A method of separation of phosphorus and phosphate fertilizer being prepared from dephosphorization steel slag, included the following steps:

(1) dephosphorization steel slag carries out oxidation processes in the molten state first, makes the mass fraction of FeO in steel slag lower than 8%, After Slow cooling, crushing grinding is carried out to dephosphorization steel slag；

(2) the resulting dephosphorization steel slag of step (1) is mixed with aqueous solution and carries out Selectively leaching；Selectively leaching process In, the pH value using hydrochloric acid and/or nitric acid solution control ore pulp is 3.0~4.5, after reaction, isolated low-phosphorous residue and is contained Phosphorus leachate, low-phosphorous residue use in Ferrous Metallurgy；

(3) alkaline matter is added into the resulting phosphorous leachate of step (2), increases the pH value of leachate, until having big The white precipitate of amount generates, and the precipitating after separation mainly contains synthos, can use directly as phosphate fertilizer.

In the step (1) during Slow cooling, when steel slag is cooled to 1100 DEG C from molten condition, cooling velocity is controlled Lower than 10 DEG C/min.

In the step (1) after crushing grinding, the granularity of dephosphorization steel slag is less than 0.1mm.

In the step (2) during Selectively leaching, mechanical stirring is carried out to ore pulp.

The alkaline matter added in the step (3) is calcium hydroxide and/or sodium hydroxide.

In the step (3) after addition alkaline matter, the pH value of leachate is increased to 7.5~9.0.

Gravitational settling and/or centrifuge separation are utilized in the step (3), separation and Extraction precipitates from leachate.

Compared with prior art, the present invention has following advantageous effects:

Separation of phosphorus and the method for preparing phosphate fertilizer, specifically execution step and smelting from dephosphorization steel slag that the invention proposes a kind of Golden principle is as follows:

(1) a kind of separation of phosphorus from steel slag proposed by the present invention and the method for preparing phosphate fertilizer have been achieved at low cost dephosphorization steel The high-efficiency resource recycling of slag achieves the important breakthrough that phosphate fertilizer is prepared from metallurgical by-product, establishes green Ferrous Metallurgy Process.

(2) present invention can make to be more than that 93% phosphorus is separated and is dissolved into solution in dephosphorization steel slag, and the dissolution rate of iron is lower than 0.1%, the separation of rich phosphorus solid solution phase and iron-bearing mineral phase in steel slag is farthest realized, ideal selectivity has been reached It leaches.Low-phosphorous residue mainly contains the elements such as iron, calcium, manganese, can be used as flux for metallurgy and recycles in sintering or steel-making, realizes The maximum value of valuable element in steel slag, has saved a large amount of Metallurgical resources, has reduced production cost.

(3) present invention utilizes Selectively leaching and chemical precipitation, be more than in dephosphorization steel slag 92% phosphorus with phosphate product Form be recovered.P in the phosphate product₂O₅Mass fraction be more than 35%, and silicone content is lower, can be directly as phosphorus Fertilizer uses.Therefore, the technology of the present invention can create huge economic benefit, save a large amount of phosphate rock resource, promote society can Sustainable development.

(4) the technology of the present invention can be such that the dephosphorization steel slag generated in steel-making recycles in Ferrous Metallurgy process, realize " nothing Waste residue " steel-making, not only promotes the energy-saving and emission-reduction of steel and iron industry, but also protect ecological environment.

(5) the technology of the present invention uses cheap hydrochloric acid or nitric acid, also uses common calcium hydroxide in industry Or sodium hydroxide.Entire process flow all carries out under faintly acid and weak basic condition.The technology of the present invention has simple process, if Standby to require low, high production efficiency, processing cost is low, has good market promotion prospect, can large-scale application in industrial production.

Detailed description of the invention

Fig. 1 is the separation of phosphorus and the process flow for preparing phosphate fertilizer in dephosphorization steel slag；

Fig. 2 is electron probe (EPMA) picture of steel slag 2 in embodiment 1；

Fig. 3 is the dissolution rate of each element in two kinds of steel slags in embodiment 1；

Fig. 4 is the photo of the phosphate fertilizer product prepared in embodiment 1；

Fig. 5 is the dissolution rate of each element in each steel slag in embodiment 2.

Specific embodiment

Below with reference to embodiment and attached drawing, the present invention is described in detail, but protection scope of the present invention is not by embodiment It is limited with attached drawing.

Fig. 1 is that the separation of phosphorus is with the process flow for preparing phosphate fertilizer in dephosphorization steel slag, the process flow that the technology of the present invention proposes As shown in the figure.