CN109652462B

CN109652462B - Method for utilizing organic matters in phosphogypsum

Info

Publication number: CN109652462B
Application number: CN201810308594.0A
Authority: CN
Inventors: 谭宏斌; 刘明学; 董发勤; 马小玲; 王进; 贺小春; 刘玉川; 王宝强
Original assignee: Southwest University of Science and Technology
Current assignee: Sichuan Diwei Technology Co.,Ltd.
Priority date: 2018-04-09
Filing date: 2018-04-09
Publication date: 2022-02-11
Anticipated expiration: 2038-04-09
Also published as: CN109652462A

Abstract

The patent discloses a method for utilizing organic matters in phosphogypsum, which comprises the steps of adding water, a gypsum modifier, a foaming agent and an inhibitor into the phosphogypsum, uniformly stirring, and then obtaining organic foam through air. Adding an acid neutralizer, a pH stabilizer, microorganisms and a carbon source into the organic foam, and carrying out closed fermentation reaction to obtain the biogas. The method has low production cost and high efficiency, and realizes resource recycling.

Description

Method for utilizing organic matters in phosphogypsum

Technical Field

The invention relates to the field of resource utilization of industrial waste residues, in particular to a method for recovering organic matters from phosphogypsum, which can also be used for recovering organic matters from other industrial byproducts.

Background

Gypsum is a sulfate mineral and has a chemical formula of caso 4. xh2 o. The gypsum is divided into natural gypsum and industrial by-product gypsum. At present, the industrial by-product gypsum is mainly phosphogypsum, desulfurized gypsum and titanium gypsum.

Phosphogypsum is a byproduct of wet-process phosphoric acid industry, and about 4.5-5.0 tons of phosphogypsum are produced when 1 ton of phosphate fertilizer (calculated as P2O 5) is produced. According to statistics, the discharge amount of phosphogypsum in China reaches 8000 million tons in 2014, and the stacking amount of the phosphogypsum in the past year is accumulated to exceed 3 hundred million tons. On a national scale, the comprehensive utilization rate of phosphogypsum in 2015 in China is only 30%. And the residual gypsum is stacked nearby, and enterprises spend a large amount of expenses for building a slag yard and operating and managing the slag yard each year. Phosphogypsum contains impurities such as undecomposed phosphorite, free phosphoric acid, fluoride and the like, and a large amount of stacking causes environmental problems and pollutes soil, atmosphere and water. How to properly handle and treat it is an important issue it faces.

The organic matters in the phosphogypsum are ethylene glycol methyl ether acetate, isothiocyanic methane, 3-methoxyl n-pentane and 2-ethyl-1, 3-dioxolane. The organic matter is mainly distributed on the surface of the gypsum crystal in a physical adsorption mode, and the content is about 0.1-0.2%. It prolongs the cement setting time, reduces the strength, and especially greatly reduces the 28-day compressive strength [ Zhang Jianxin, Penjiahui, Wangzhi ] determination of organic matters in phosphogypsum and the influence thereof on the cement performance [ J ]. university of Sichuan bulletin (engineering science edition), 2006, 38 (3): 110-113].

Biogas is a mixed gas produced by the fermentation of organic substances under anaerobic conditions. The main component of biogas is methane. The biogas consists of 50-80% of methane (CH 4), 20-40% of carbon dioxide (CO 2), 0-5% of nitrogen (N2), less than 1% of hydrogen (H2), less than 0.4% of oxygen (O2), 0.1-3% of hydrogen sulfide (H2S) and the like. The main component of methane is an ideal gas fuel, which is colorless and odorless and can be combusted after being mixed with a proper amount of air. The calorific value of pure methane per cubic meter is 34000 kilojoules, and the calorific value of methane per cubic meter is 20800 kilojoules and 23600 kilojoules. Namely, 1 cubic meter of methane can generate heat equivalent to that provided by 0.7 kilogram of anthracite after being completely combusted. Compared with other fuel gases, the fuel gas has better anti-explosion performance and is a good clean fuel.

Although many studies suggest that organic matter can be removed by flotation, flotation is reported to be less effective with any chemical. In addition, the recycling of the floated organic matters is less reported.

The organic matters in the phosphogypsum can be collected to be used as the raw material of the biogas according to the characteristics of the organic matters.

Disclosure of Invention

Compared with the prior art, the method can save the production cost, improve the efficiency and realize the cyclic utilization of resources. Can obviously improve the quality of the phosphogypsum product and has obvious economic and social benefits.

A method for utilizing organic matters in phosphogypsum comprises the following steps:

adding water, a gypsum modifier, a foaming agent and an inhibitor into phosphogypsum, uniformly stirring, blowing air into the solution to obtain organic foam, and collecting the organic foam. Wherein the mass of the water is 100-500% of the mass of the phosphogypsum; the gypsum modifier is one of a protein modifier, a fat modifier and sulfonated melamine formaldehyde resin, and the addition amount of the gypsum modifier is 0.1-1.0% of the mass of the phosphogypsum; the foaming agent is: one of methanol, terpene alcohol, sec-octanol, methyl amyl alcohol, triethoxy butane, pyridine, alkyl sulfonic acid and carboxylic acid, and the adding amount is 0.1-1.0% of the weight of phosphogypsum; the inhibitor is one of starch and dextrin, and the addition amount of the inhibitor is 0.1-1.0% of the mass of the phosphogypsum.

Adding an acid neutralizer, a pH value stabilizer, microorganisms and a carbon source into the organic foam, and carrying out closed fermentation reaction to obtain the biogas. Wherein the acid neutralizer is one of lime and carbide slag, and the addition amount is 0.5-5.0% of the weight of the phosphogypsum; the pH value stabilizer is one of limestone, marble and chalk, and the addition amount of the pH value stabilizer is 0.5-5.0% of the mass of the phosphogypsum.

The protein modifier is prepared from animal protein, and the fat modifier is prepared from animal fat.

The microorganism comprises zymogenic bacteria, hydrogen-producing acetogenic bacteria, hydrogen-consuming acetogenic bacteria, hydrogen-feeding methanogenic bacteria and acetic acid methanogenic bacteria.

The carbon source comprises plant straws and human and animal excreta.

And removing the foam from the water and the phosphogypsum, separating by using a filter press, neutralizing the filtrate into neutral by using lime or carbide slag, and recycling, wherein the phosphogypsum is used in the field of building materials.

Compared with the prior art, the invention has the following advantages:

organic matter is often adsorbed on the surface of phosphogypsum, thereby affecting the performance of gypsum. The phosphogypsum is added with a gypsum modifier, the gypsum modifier has strong adsorption capacity with gypsum, and organic matters are exchanged from the surface of the gypsum. In addition, the gypsum modifier has less impact on the performance of the cement. The protein modifier is prepared by adding lime or sodium hydroxide into animal protein and heating for reaction. The fat modifier is prepared by adding lime or sodium hydroxide into animal fat and heating for reaction. The sulfonated melamine-formaldehyde resin is a product obtained by sulfonating melamine by sulfuric acid and then condensing the melamine with formaldehyde.

The foaming agent mainly reduces the surface tension of water, is a common foaming agent and has the characteristics of easily obtained raw materials and low price.

The phosphogypsum usually contains a small amount of amorphous silicon dioxide and ferric oxide, and is easy to float upwards along with bubbles when air is blown, and the inhibitor is added to avoid the floating upwards and reduce the impurity content of organic matters.

Phosphogypsum is generally acidic, the growth of microorganisms is influenced by acidic conditions, and the pH value of the solution can be adjusted by adding an acid neutralizing agent, so that the growth of the microorganisms is facilitated.

The pH stabilizer can stabilize organic foam in a neutral environment, and is beneficial to the growth of microorganisms.

The microorganism is a common microorganism for producing biogas, and comprises: zymogenic bacteria, hydrogen-producing acetogenic bacteria, hydrogen-consuming acetogenic bacteria, methanogenic bacteria. The microorganisms can adapt to the toxicity of the phosphogypsum organic matters through domestication. The total number of added microorganisms is about 108 for 100kg of organic matter produced by phosphogypsum.

The carbon source is plant straw and human and animal excreta, can provide nutrition for microorganisms and promote the generation of methane.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

(1) Adding water (100 mass percent and 500 mass percent of phosphogypsum), a gypsum modifier (0.1-1.0 mass percent of phosphogypsum), a foaming agent (0.1-1.0 mass percent of phosphogypsum) and an inhibitor (0.1-1.0 mass percent of phosphogypsum) into 100Kg of phosphogypsum, uniformly stirring, blowing air to obtain organic foam, and collecting the foam.

(2) Adding an acid neutralizer (0.5-5.0% of the mass of the phosphogypsum), a pH stabilizer (0.5-5.0% of the mass of the phosphogypsum), microorganisms (108) and a carbon source (100% of the mass of the phosphogypsum) into the organic foam, and carrying out closed fermentation reaction to obtain the biogas.

The following table shows 32 examples numbered 1-32. In examples 1-32, the removal rate of organics in phosphogypsum was greater than 98% by collecting the organic foam after blowing air. Through microbial fermentation, the decomposition rate of organic matters in the organic foam is 100 percent. The amount of water added in example 1 was 100Kg, the amount of water added in example 2 was 500Kg, and the amounts of water added in examples 3 to 32 were all 300 Kg.

TABLE 1

TABLE 2

Claims

1. The method for utilizing the organic matters in the phosphogypsum is characterized by comprising the following steps of:

(1) adding water, a gypsum modifier, a foaming agent and an inhibitor into phosphogypsum, uniformly stirring, blowing air into the solution to obtain organic foam, and collecting the organic foam; wherein the mass of the water is 100-500% of the mass of the phosphogypsum; the gypsum modifier is one of a protein modifier, a fat modifier and sulfonated melamine formaldehyde resin, the addition amount of the gypsum modifier is 0.1-1.0 percent of the mass of the phosphogypsum, the protein modifier is prepared from animal protein, and the fat modifier is prepared from animal fat; the foaming agent is: one of methanol, terpene alcohol, sec-octanol, methyl amyl alcohol, triethoxy butane, pyridine, alkyl sulfonic acid and carboxylic acid, and the adding amount is 0.1-1.0% of the weight of phosphogypsum; the inhibitor is one of starch and dextrin, and the addition amount of the inhibitor is 0.1 to 1.0 percent of the mass of the phosphogypsum;

(2) adding an acid neutralizer, a pH value stabilizer, microorganisms and a carbon source into the organic foam, and carrying out closed fermentation reaction to obtain biogas; wherein the acid neutralizer is one of lime and carbide slag, and the addition amount is 0.5-5.0% of the weight of the phosphogypsum; the pH value stabilizer is one of limestone, marble and chalk, and the addition amount of the pH value stabilizer is 0.5-5.0% of the mass of the phosphogypsum; wherein the microorganism comprises zymogenic bacteria, hydrogen-producing acetogenic bacteria, hydrogen-consuming acetogenic bacteria, methanogen hydrogenotrophus and methanogen acetogenic bacteria; the carbon source comprises plant straw and human and animal excreta.