CN86105794A

CN86105794A - Method for producing sulfur magnesium fertilizer with magnesite as raw material

Info

Publication number: CN86105794A
Application number: CN86105794.5A
Authority: CN
Inventors: 仝兆胜
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-07-25
Filing date: 1986-07-25
Publication date: 1987-01-31
Also published as: CN1007892B

Abstract

以菱镁矿为原料生产硫镁肥的工艺方法涉及一种生产复合肥料添加剂一水硫酸镁的工艺方法，其目的是克服现有技术生产工艺复杂、能耗高、成本高的缺陷，并充分利用天然菱镁矿资源。本发明将天然菱镁矿经过焙烧后所得的轻烧氧化镁与适当浓度的硫酸反应，直接生成一水硫酸镁。本发明适用于以天然菱镁矿或轻烧氧化镁为原料生产硫镁肥。The process for producing sulfur-magnesium fertilizer using magnesite as raw material relates to a process for producing magnesium sulfate monohydrate as a compound fertilizer additive. Utilize natural magnesite resources. The invention reacts light-burned magnesia obtained by roasting natural magnesite with sulfuric acid of appropriate concentration to directly generate magnesium sulfate monohydrate. The invention is suitable for producing sulfur-magnesium fertilizer by using natural magnesite or light-burned magnesia as raw materials.

Description

With magnesite is the method for raw material production kieserite

The present invention relates to a kind of processing method of producing the composite fertilizer additive magnesium sulfate monohydrate.

Magnesium can promote the absorption of plant materials to phosphorus, and it is one of indispensable element in the plant materials.Kieserite or fertilizer sal epsom are a kind of important additive of producing compound manure, and its main component is the magnesium sulfate salt that contains crystal water.In order to improve (MgO) content of magnesium oxide in the kieserite and sulphur (S) content, prior art generally is to utilize some chemical reaction to make magnesium sulfate heptahydrate (MgSO earlier ₄7H ₂And then magnesium sulfate heptahydrate is added thermal bake-out become magnesium sulfate monohydrate (MgSO O), ₄H ₂O), the common chemical reaction has:

The method of this production magnesium sulfate monohydrate is owing to need add thermal bake-out, thereby technology is complicated, and energy consumption is higher, thereby production cost is also than higher.

Except that above-mentioned chemical process, also having a kind of method is to isolate the sal epsom of band crystal water from the natural mineral intergrowth of magnesium salts and boron.This isolating method not only needs through complicated ore-dressing technique and separating technology, but also is subjected to the restriction of the natural mineral intergrowth reserves of magnesium salts and boron on the earth.The reserves of this natural mineral intergrowth are very little, then still find no this kind mineral reserve of extraction value in China.But the reserves of the magnesite of China (mainly containing magnesiumcarbonate) are but very abundant, are the important source material that can be used to produce kieserite.

The objective of the invention is to obtain a kind of is the processing method of raw material direct production-water magnesium sulfate with the magnisite, processing method complex process, energy consumption height, defect of high cost to overcome prior art production-water magnesium sulfate make full use of the magnisite resource simultaneously.

In order to achieve the above object, the present invention is with magnisite (MgCO ₃) at suitable roasting temperature, again with the sulfuric acid (H of resulting light calcined magnesia (MgO) after the roasting with proper concn ₂SO ₄) reaction, and utilize the reaction heat direct production of this reaction to go out magnesium sulfate monohydrate (MgSO ₄H ₂O).This processing method mainly comprises sinter process, reaction process and three technological processs of disintegrating process, and accompanying drawing 1 is the process flow diagram of this processing method, below in conjunction with embodiment main points of the present invention is further described.

The raw material that this processing method adopted is a magnisite, and its main component is the MgCO of unbound state ₃MgCO with hydrate forms ₃H ₂O and MgCO ₃5H ₂O.

Roasting in this processing method is carried out magnisite under proper temperature in stoving oven, all sinter process carries out according to the following steps in proper order:

(1) will pack in the stoving oven through selected giobertite.Stoving oven can be any in shaft furnace, rotary kiln, multilayer mechanical kiln or the fluidizing furnace, and the employed fuel of stoving oven can be coal or Sweet natural gas.

(2) with the stoving oven firing up.The main component of magnisite will be decomposed into magnesium oxide (MgO) and carbon dioxide (CO when adding thermal bake-out ₂), magnesian acidproof, the water resistance and the maturing temperature relation that are generated after the roasting are very big, and at high temperature burnt magnesium oxide is very hard solid, and has acidproof and water tolerance.In the present invention, for the magnesium oxide that roasting is generated can react with sulfuric acid in next reaction process, the furnace temperature of stoving oven must be strict controlled in 800～900 ℃, the highlyest must not surpass 900 ℃, and best furnace temperature is about 850 ℃.Under this temperature condition the roasting magnisite resulting will be a kind of light calcined magnesia it be the powder of a kind of pine, be easy to be dissolved in acid and generate magnesium salts.

(3) under 800～900 ℃ furnace temperature, kept 10～15 hours, for example kept 12 hours.Under this temperature condition, magnisite can be decomposed into light calcined magnesia and carbon dioxide, and its chemical equation is:

(4) come out of the stove, natural cooling, removal of impurities, pulverizing, selection by winnowing.The granularity of the light calcined magnesia after the pulverizing is advisable at 60～100 orders.

Reaction in this processing method is that the sulfuric acid with the light calcined magnesia of gained behind sinter process and proper concn carries out at reactor.Total overall reaction technology order is according to the following steps carried out:

(1) complex acid.Sulfuric acid (H ₂SO ₄) with the chemical reaction of magnesium oxide (MgO) be thermopositive reaction, directly generate magnesium sulfate monohydrate in order to make full use of reaction heat, do not make reaction too violent again simultaneously, must strict control vitriolic concentration.Vitriolic concentration is 70～80% among the present invention, and optimum concn is 75%.In order to obtain expecting the sulfuric acid of concentration, used water (H ₂O) dilution industrial sulphuric acid, for example concentration is 98% or 92.5% the industrial vitriol oil.Complex acid can directly carry out in reactor, for example, earlier a certain amount of water is added reactor, again the certain amount of industrial vitriol oil is slowly added reactor, make that vitriolic concentration reaches predetermined range in the reactor, the continuous acid solution in the stirred reactor when adding the industrial vitriol oil.

(2) add light calcined magnesia in the sulphuric acid soln in reactor.Because the reaction of the industrial vitriol oil and water and magnesium oxide subsequently all are thermopositive reaction with the vitriolic reaction, one reacts too violent for fear of the back, adding light calcined magnesia when should the acid liquor temperature in reactor dropping to 40～60 ℃.In order to guarantee that the content of magnesian content and sulphur all reaches the ideal standard in the finished product kieserite, the amount that adds the light calcined magnesia in the reactor acid solution must strictly be controlled, the weight ratio of sulphuric acid soln is (45～55) in light calcined magnesia among the present invention in the adding reactor acid solution and the reactor: 100, for example 50: 100, the bound of weight ratio was preferably corresponding with the bound of sulfuric acid concentration.Light calcined magnesia should add in the sulfuric acid of reactor lentamente, and the reactant in the simultaneously abundant stirred reactor is till the pH value of the reactant in reactor reached 6～7 o'clock.Because the reaction of sulfuric acid and light calcined magnesia will discharge a large amount of reaction heat, therefore, utilize this reaction can directly obtain magnesium sulfate monohydrate, its chemical equation is:

Disintegrating process in this processing method is about to the magnesium sulfate monohydrate of above-mentioned reaction gained and is pulverized so that prepare compound manure.Because above-mentioned reaction is carried out very soon, its reaction product magnesium sulfate monohydrate is rapid hardening after cooling, and therefore, disintegrating process in time carries out before should being reduced to 50 ℃ in the temperature of reaction product.

So far, be that the main technique of raw material production magnesium sulfate monohydrate finishes with the magnisite, magnesium sulfate monohydrate is after crushed tested, packed promptly obtain the kieserite finished product.

The present invention is owing to be raw material with the magnisite, and utilize light calcined magnesia and vitriolic thermopositive reaction dexterously and direct production goes out magnesium sulfate monohydrate, thereby simplified the kieserite production technique, reduce energy consumption and production cost, and might make full use of the magnisite resource.Utilize the content of magnesia of the kieserite that the present invention produces can reach more than 26%, sulphur content can reach more than 16%, and since fine size not only be convenient to prepare compound manure, and have instant, quick-acting characteristics.

The present invention has the remarkable economical effect, and can be widely used in magnisite or light calcined magnesia is the occasion of raw material direct production kieserite.

Claims

1. A process for producing magnesium sulfate monohydrate ( _MgSO4 · _H2O ), a compound fertilizer additive. The prior art generally utilizes certain chemical reactions to first produce magnesium sulfate heptahydrate ( _MgSO4 · _7H2O ), which is then roasted to produce magnesium sulfate monohydrate. The present invention is characterized in that it uses natural magnesite as a raw material and directly produces magnesium sulfate monohydrate through the main processes of roasting, reaction, and crushing. That is, natural magnesite is first roasted at an appropriate temperature to produce light-burned magnesium oxide (MgO), and then the roasted light-burned magnesium oxide is reacted with sulfuric acid ( _H2SO4 ) of an appropriate concentration to directly produce magnesium sulfate _monohydrate , which is then crushed in a timely manner.

2. A process according to claim 1, characterized in that the roasting process is carried out in the following order:

(1) loading the selected natural magnesite ore into a roaster;

(2) Ignite the roasting furnace and raise the temperature to 800-900°C;

(3) Maintaining the above furnace temperature for 10 to 15 hours;

(4) Unloading, natural cooling, impurity removal, crushing, and air separation.

3. A process according to claim 1, characterized in that the reaction process is carried out in the following order:

(1) Acid preparation: diluting industrial concentrated sulfuric acid (e.g., 98% or 92.5% concentrated sulfuric acid) with water (H ₂ O) to a concentration of 70-80% sulfuric acid (H ₂ SO ₄ ). The acid solution in the reactor must be stirred continuously during dilution.

(2) When the temperature of the acid solution in the reactor drops to 40-60°C, slowly add a certain amount of light-burned magnesium oxide (MgO) into the reactor and fully stir the reactants in the reactor until the pH value of the reactants reaches 6-7.

4. A process according to claim 3, characterized in that the weight ratio of light-burned magnesium oxide to sulfuric acid solution added to the reactor is (45-55):100, with the upper and lower limits corresponding to the upper and lower limits of sulfuric acid concentration.

5. A process according to claim 1, wherein the pulverization process must be carried out before the temperature of the reaction product drops to 50°C.