WO2016019774A1

WO2016019774A1 - Method for preparing chlorine-removal alkali residue mixture by utilizing alkali residues through ammonia-soda process and application thereof

Info

Publication number: WO2016019774A1
Application number: PCT/CN2015/083350
Authority: WO
Inventors: 杨医博; 郭文瑛; 莫海鸿; 王恒昌
Original assignee: 华南理工大学
Priority date: 2014-08-06
Filing date: 2015-07-06
Publication date: 2016-02-11
Also published as: JP6404948B2; JP2017520391A; CN104190690B; CN104190690A

Abstract

A method for preparing a chlorine-removal alkali residue mixture by utilizing alkali residues through an ammonia-soda process. The method comprises the following steps: step 1, crushing returned sand and returned stones, and grinding to obtain returned sand and returned stone powder; step 2, soaking the returned sand and returned stone powder in water for 0.5-14 days, digesting the burnt calcium oxide, then mixing the digested returned sand and returned stone powder, alkali residues and water, wherein the ratio of dry mass of the digested returned sand and returned stone powder to the alkali residues is 2:8 to 5:5 based on the mass percentage of the materials, and the total mass of the water is 1.5 to 8 times as much as the total dry mass of the digested returned sand and returned stone powder and alkali residues; or mixing the returned sand and returned stone powder, the alkali residues and water, then soaking the mixture for 0.5-14 days, and digesting the burnt calcium oxide; step 3, performing filter-pressing treatment, then obtaining the chlorine-removal alkali residue mixture of which the chloride ion content is lower than 0.30 percent of the total mass of solids in the mixture. An application of the chlorine-removal alkali residue mixture. The method is good in chlorine removal effect, simple in process, energy-efficient and environmentally-friendly.

Description

Method and application for preparing mixture of chlor-alkali residue by using alkali-base alkali residue

Technical field

The invention belongs to the field of industrial solid waste treatment, and particularly relates to an alkali alkali residue and a sand returning stone treatment method and an application method thereof.

Background technique

As a basic chemical raw material, soda ash is mainly used in construction materials, chemicals, chemical pesticides, non-ferrous metals, textiles and other industries. It plays an important role in the national economy and is known as the “mother of chemical industry”. At present, the production of soda ash mainly includes the trona method, the ammonia-alkali method and the combined alkali method. The production of soda ash in China is mainly based on the ammonia-alkali method.

Alkali slag is an industrial waste residue produced during the process of producing soda ash by the ammonia-base method. The main components of the alkali slag are calcium carbonate, calcium sulfate and oxides such as aluminum, iron and silicon, and contain a large amount of chloride. For every ton of soda ash produced, about 350kg of alkali slag will be produced. The annual production of alkali slag in China exceeds 300. Ten thousand tons.

Alkali slag is a worldwide problem due to its high alkalinity and high chloride ion content. In order to make rational use of alkali slag, a lot of research has been carried out at home and abroad. The main methods of its use are to prepare engineering soil for land preparation, dam construction, roadbed and pavement base layer, etc. In addition, soil improver and smoke are prepared by using alkali residue. Research on gas desulfurizer, gypsum, cement, high-expansion cementitious materials, construction mortar, alkali slag brick, alkali slag fly ash brick, asphalt filler, rubber filler, artificial reef and so on. However, how to effectively reduce the chloride ion content in the alkali residue has not been broken, and the excessive chloride ion content in the alkali residue after treatment also affects its application in various fields.

Looking at the treatment of alkali residue at home and abroad, in the 20th century In the United States, after mastering the natural alkali processing technology, the United States quickly eliminated all ammonia plants in the United States. The ammonia plant in Canada, South Korea and Japan has also been phased out. However, China's trona content is scarce, it is impossible to completely eliminate the ammonia plant. At present, the domestic ammonia-alkali plant still mainly adopts two methods of land dumping or external reclamation, which will cause serious environmental pollution problems.

At present, the most effective method for dechlorination of alkali residue is water washing and dechlorination, but the washing efficiency is low, multiple washings are required, and a large amount of water is consumed, which also seriously affects its application. In order to reduce the water consumption, only the higher chloride ion content can be controlled. Usually, the chloride ion content of the alkali residue is controlled at 1.5% after one water washing and pressure filtration. Left and right. The high-efficiency dechlorination method of alkali slag has become a major problem that restricts the sustainable development of the soda ash industry.

In addition to the alkali slag, the solid waste of the soda ash plant also has a returning sand returning stone, which is generated for each ton of soda ash produced.

165kg Return to the sand and return to the stone. Its main component is calcium carbonate. Because it contains super-calcined calcium oxide, it has been used for paving and shaft kiln cement raw materials for a long time. Although it has low utilization value, most of it can be consumed. With the improvement of road quality requirements and the elimination of vertical kiln cement plants, the utilization rate has declined, and it is urgent to seek new ways of utilization.

Summary of the invention

The object of the present invention is to provide a chlorine removal alkali slag mixture by using an alkali-base alkali residue for good chlorine removal effect.

Methods.

The object of the invention is achieved by the following technical solutions:

A method for preparing a mixture of chlor-alkali residues by using an alkali-base alkali residue, comprising the steps of:

Step 1. First, returning the sand to the stone and crushing it into a sand returning powder;

Step 2. Soak the returning stone powder in water 0.5 to 14 After dissolving the calcined calcium oxide, the digested returning stone powder, alkali residue and water are mixed, and the ratio of the dry mass of the returned sand powder and the alkali residue after digestion is 2:8. To 5 : 5, the total mass of water is 1.5 to 8 times the total dry mass of the returned sand returning powder and alkali residue after digestion;

or,

Mix back sand powder, alkali residue and water and soak 0.5 to 14 The calcined calcium oxide is dissolved in days, and the ratio of the mass of the returned sand powder to the alkali residue is 2:8 to 5:5, and the total mass of the water is the total dry mass of the returning stone powder and the alkali residue. 1.5 to 8 times;

Step 3. Perform a pressure filtration treatment to obtain a dechlorination alkali residue mixture having a chloride ion content of 0.30% lower than the total mass of the solid in the mixture.

Further, intermittent agitation is also performed during the step 2 in which the returning sand powder is immersed.

Further, the step 2 One or more of fly ash, limestone powder, slag powder, slag powder, steel slag powder and stone powder may be used to replace the returning sand powder of less than or equal to 50%.

Further, the step 2 The first method further comprises the steps of separately separating and recovering calcium hydroxide in the re-returned stone powder after digestion, and using it for soda ash production.

Another object of the present invention is to provide an application of the above-described chlorine-removing alkali residue mixture, the scheme being as follows:

According to the application of the chlorine-removing alkali residue mixture prepared according to the method, the chlorine-removing alkali residue mixture can be used as a mixed material of cement, mineral admixture of concrete and mortar, engineering soil, filler, flue gas desulfurizer, soil treatment agent , adsorbents and carriers.

Further, the chlorinated alkali residue mixture is used as a mixed material of cement, a mineral admixture of concrete and mortar, a filler, a flue gas desulfurizer, a soil treatment agent, an adsorbent and a carrier, and is first dried, crushed, and ground. The mixture was treated to obtain a powdery chlorinated alkali residue mixture.

Further, when the chlorine-removing alkali residue mixture is used as a mineral admixture of cement, concrete and mortar, the dechlorination alkali residue mixture can replace 30% or less of the cementitious material.

The alkali slag particles are small, the particle size is between several micrometers and several tens of micrometers, and contains a large amount of pores, so the moisture content and chloride ion content of the alkali slag after pressure filtration are high. The chloride ion in the alkali residue is mainly present in water, and the particle grading adjustment material may be added to reduce the porosity, thereby reducing the chloride ion content in the alkali residue after pressure filtration. In order to fully absorb the solid waste of the soda ash plant, the returning sand powder after water digestion is selected as the particle grading adjustment material. Due to the dissolution of calcium oxide, the surface of the returned sand powder after water digestion is rough, which can reduce the chloride ion content more effectively.

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

(1) The dechlorination effect of the invention is good, and the chlorine ion content (calculated as the total mass of the solid) can be made less than 0.30% by using a single water washing and pressure filtration treatment, which greatly reduces the chloride ion content compared with the conventional primary water washing pressure filtration.

(2) Due to the low content of chloride ions, it can be used in a variety of applications, so as to effectively solve the problem of treatment of alkali slag, and can be used for mixed materials of cement, mineral admixtures of concrete and mortar, engineering soil, filler, flue gas. Desulfurizer, soil treatment agent and other fields; using the porous structure of alkali residue, it can also be used in the fields of adsorbents, carriers and the like.

(3) It can simultaneously dissipate another large amount of solid waste in the soda ash plant - returning sand and returning stone, achieving the purpose of waste treatment, and using some of the calcium hydroxide to produce soda ash.

detailed description

The present invention will be further described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto.

Example 1

Step 2. Soak the returning stone powder in water 0.5 Days dissolve the burned calcium oxide, and intermittently stir when returning the sand to the stone powder, and then mix the returned sand returning powder, alkali residue and water after the digestion, based on the mass percentage of the material, the back-returned stone powder after digestion and The ratio of alkali residue is 2 : 8, the total mass of water is 8 times the total mass of returning stone powder and alkali residue after digestion;

Step 3. Perform a pressure filtration treatment to obtain a chlorinated alkali residue mixture having a chloride ion content of 0.28% of the total solid mass in the mixture.

In this embodiment, one or more of fly ash, limestone powder, slag powder, slag powder, steel slag powder and stone powder may be replaced by no more than 50%. Returning sand to stone powder.

In this embodiment, the calcium hydroxide in the re-returned stone powder after digestion is first separated and recovered, and used for soda ash production.

Example 2

Step 2. Soak the returning sand powder in water 3 Days dissolve the burned calcium oxide, and intermittently stir when returning the sand to the stone powder, and then mix the returned sand returning powder, alkali residue and water after the digestion, based on the mass percentage of the material, the back-returned stone powder after digestion and The ratio of alkali residue is 3 :7, the total mass of water is 7 times of the total mass of returning stone powder and alkali residue after digestion;

Step 3. Perform a pressure filtration treatment to obtain a chlorinated alkali residue mixture having a chloride ion content of 0.08% of the total solid mass in the mixture.

Example 3

Step 2. Soak the returning stone powder in water 7 Days dissolve the burned calcium oxide, and intermittently stir when returning the sand to the stone powder, and then mix the returned sand returning powder, alkali residue and water after the digestion, based on the mass percentage of the material, the back-returned stone powder after digestion and The ratio of alkali residue is 5 : 5, the total mass of water is 3 times the total mass of returning stone powder and alkali residue after digestion;

Step 3. Perform a pressure filtration treatment to obtain a chlorinated alkali residue mixture having a chloride ion content of 0.05% of the total solid mass in the mixture.

Example 4

Step 2, soak in water 14 Days dissolve the burned calcium oxide, and intermittently stir when returning the sand to the stone powder, and then mix the returned sand returning powder, alkali residue and water after the digestion, based on the mass percentage of the material, the back-returned stone powder after digestion and The ratio of alkali residue is 5 : 5, the total mass of water is 1.5 times the total mass of returning stone powder and alkali residue after digestion;

Step 3. Perform a pressure filtration treatment to obtain a chlorinated alkali residue mixture having a chloride ion content of 0.09% of the total solid mass in the mixture.

Example 5

Step 2. Soak the returned sand powder, alkali residue and water, and soak 0.5 The calcined calcium oxide is dissolved in days, and the ratio of the mass of the returned sand powder to the alkali residue is 2:8, and the total mass of the water is 8 times the total dry mass of the returned sand powder and the alkali residue;

Example 6

Step 2. Soak the returned sand powder, alkali residue and water, and soak 3 The calcined calcium oxide is dissolved in days, and the ratio of the mass of the returned sand powder to the alkali residue is 3:7, and the total mass of the water is 7 times the total dry mass of the returned sand powder and the alkali residue;

Example 7

The chlor-alkali residue mixture is used as a mineral admixture for concrete, and the chlor-alkali residue is formulated to have a water content of 250%. The suspension is used to replace 10% of the cement with chlor-alkali slag (dry basis). When the water-to-binder ratio is constant, the concrete strength is basically unchanged and does not cause corrosion of the steel in the structure.

Example 8

The powdered dechlorination alkali residue mixture after drying and crushing and grinding the dechlorination alkali residue mixture is used as a mixed material of cement, wherein the powdery dechlorination alkali residue mixture has a particle size of 80 The micron sieve residue is less than 5%, the amount is 30%, the amount of slag powder is 22%, the amount of cement clinker is 45%, and the amount of gypsum is 3%. Cement performance meets masonry cement 12.5 Grade requirements, and high water retention, water retention rate of 96.5%.

Example 9

The powdered dechlorination alkali residue mixture after drying and crushing and grinding the dechlorination alkali residue mixture is classified according to different particle sizes, wherein less than 3 Micron powdered chlorinated alkali residue mixture used as rubber filler, greater than or equal to 3 A micron powdered chlor-alkali residue mixture is used as a flue gas desulfurizer. The porosity of the mixture of dechlorination alkali slag is utilized to improve the mechanical properties of the rubber and the efficiency of the flue gas desulfurizer. When used as a flue gas desulfurizer, it can replace the limestone powder originally used, saving energy and environmental protection.

Example 10

When the chlor-alkali residue mixture is used in engineering soil, it can be directly used for earthwork filling, and the chlorine ion content is low, and it will not cause harm to the environment.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments, and any other changes, modifications, substitutions, and combinations may be made without departing from the spirit and scope of the present invention. And simplifications, all of which are equivalent replacement means, are included in the scope of protection of the present invention.

Claims

A method for preparing a mixture of chlor-alkali residues by using an alkali-base alkali residue, characterized in that it comprises the steps of:

Step 1. First, returning the sand to the stone and crushing it into a sand returning powder;

Step 2. Soak the returning stone powder in water 0.5 to 14 After dissolving the calcined calcium oxide, the digested returning stone powder, alkali residue and water are mixed, and the ratio of the dry mass of the returned sand powder and the alkali residue after digestion is 2:8. To 5 : 5, the total mass of water is 1.5 to 8 times the total dry mass of the returned sand returning powder and alkali residue after digestion;

or,

The sand-returned stone powder, alkali residue and water are mixed and soaked for 0.5 to 14 days to dissolve the calcined calcium oxide. The ratio of the mass of the returned stone powder and the alkali residue is 2 : 8 to 5:5, the total mass of water is 1.5 to 8 times the total dry mass of the returning stone powder and alkali residue;

Step 3. Perform a pressure filtration treatment to obtain a dechlorination alkali residue mixture having a chloride ion content of 0.30% lower than the total mass of the solid in the mixture.
The method for preparing a mixture of chlor-alkali residues by using an alkali-base alkali residue according to claim 1, wherein the step 2 Intermittent agitation is also carried out during the immersion of the returning sand powder.
The method for preparing a mixture of chlor-alkali residues by using an alkali-base alkali residue according to claim 1 or 2, wherein the step 2 One or more of fly ash, limestone powder, slag powder, slag powder, steel slag powder and stone powder may be used to replace the returning sand powder of less than or equal to 50%.
The method for preparing a mixture of chlor-alkali residues by using an alkali-base alkali residue according to claim 1, wherein the step 2 The first method further comprises the steps of separately separating and recovering calcium hydroxide in the re-returned stone powder after digestion, and using it for soda ash production.
According to claims 1 to 4 The use of the chlor-alkali residue mixture prepared by the method according to any one of the preceding claims, wherein the chlorinated alkali residue mixture is used as a mixed material of cement, a mineral admixture of concrete and mortar, engineering soil, filler, flue gas Desulfurizer, soil treatment agent, adsorbent and carrier.
According to claim 5 The application is characterized in that the chlorinated alkali residue mixture is used as a mixed material of cement, a mineral admixture of concrete and mortar, a filler, a flue gas desulfurizer, a soil treatment agent, an adsorbent and a carrier, Drying, crushing and grinding treatment to obtain a powdery mixture of chloralkali residues.
According to claim 5 The application is characterized in that, when the chlorine-removing alkali residue mixture is used as a mixed material of cement, a mineral admixture of concrete and mortar, the chlor-alkali residue mixture can be replaced by 30% or less. Gelling material.