WO2013143236A1

WO2013143236A1 - Method for recycling acidolysis residue from production of titanium white by sulphuric acid process

Info

Publication number: WO2013143236A1
Application number: PCT/CN2012/078187
Authority: WO
Inventors: 刘不尽; 朱全芳; 蔡平雄; 陈建; 孙润发; 曾小林
Original assignee: 四川龙蟒钛业股份有限公司
Priority date: 2012-03-31
Filing date: 2012-07-04
Publication date: 2013-10-03
Also published as: CN102602990B; CN102602990A

Abstract

Provided is a method for recycling an acidolysis residue from the production of titanium white by a sulphuric acid process, comprising (1) adding water and pulping: sending the acidolysis residue to a pulping tank and mixing with water and pulping, so as to form a suspension slurry having a solid content of 10% - 50%; (2) separating: separating the suspension slurry into components of different densities by a hydraulic cyclone; and (3) recycling: obtaining enriched mineral titanium concentrate from the sediment nozzle of the cyclone, and after the pressure filtration of overflow material, taking the filtrate containing a majority of titanium oxysulphate as leaching water, recycling the titanium resources, and stacking the filter cakes after an innocuous chemical treatment by mixing same with limestone. By means of highly efficient hydraulic cyclone technology and using the difference in densities of various components, the mineral titanium concentrate is recovered without introducing new impurities, thereby preventing new contaminants. The soluble titanium is also recovered at the same time as the mineral titanium concentrate, reducing the level of residuedischarged and improving the recovery rate of titanium dioxide.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering waste residue, particularly a method for recovering and utilizing acid residue in a process for producing titanium dioxide by a sulfuric acid process.

Background technique

Titanium dioxide, the scientific name of titanium dioxide (Ti0 ₂ ), is an important white pigment widely used in plastics, paper, printing inks, chemical fiber, rubber, cosmetics and other fields. The production methods are mainly sulfuric acid method and chlorination method. The sulfuric acid method is an acid hydrolysis reaction of titanium concentrate and concentrated sulfuric acid to obtain titanium sulfate, and then hydrolyzed to form metatitanic acid. After the metatitanic acid is removed, the titanium dioxide is obtained by calcination, intermediate pulverization and post-treatment. The advantage of the sulfuric acid method is that the ilmenite and sulfuric acid which are easy to obtain at low cost can be used as raw materials, and the technology is mature and the equipment is simple. The disadvantage is that the process is long, the by-products are many, and the treatment is difficult.

The commercial production methods of titanium dioxide include sulfuric acid method and chlorination method. The sulfuric acid method is mature and reliable, and it is a commonly used process in the domestic titanium dioxide production industry. The main raw material of the sulfuric acid process titanium dioxide production process is titanium concentrate, the composition of which is iron titanate, and the active ingredient titanium dioxide generally ranges from 45% to 55%. After the purchased titanium concentrate is pulverized by a Raymond mill or a ball mill, it is mixed with concentrated sulfuric acid in a solubilizing pot according to the calculated amount, and diluted with water, and the acid hydrolysis reaction is initiated by the dilution heat of concentrated sulfuric acid to form a loose porous solid phase substance. After aging, water leaching, iron powder reduction and other processes, it becomes an acidolytic titanium solution. The main components of the titanium liquid are an aqueous solution of titanyl sulfate, ferrous sulfate and dilute sulfuric acid, in addition to a small amount of unacidified titanium concentrate. , argillaceous minerals, pyroxene, magnesium aluminate spinel, hornblende, chlorite, olivine, quartz, pyrrhotite and pyrite, etc., the composition of these solid phase materials with the composition of titanium concentrate Change and change. In order to produce a clean titanium oxysulfate solution that meets the requirements of the titanium dioxide production process, these solid phase impurities must be removed by settling in the next step. In the sedimentation process, a cationic flocculant is added to the acid-decomposing titanium liquid to capture the unreacted solid particles and the colloidal substance formed in the acid hydrolysis, and the titanium liquid in the upper part of the sedimentation tank is sent to the subsequent work. The lower layer contains a large amount of solid phase impurities and is filtered through a filter press. The filtrate is sent to a subsequent stage. The filter cake is generally deposited as waste. Since the filter cake is composed of substances that are not reacted during the acid hydrolysis process, the industry generally It is called acid hydrolysis residue.

This acid hydrolysis slag generally contains about 25% water, about 3% soluble titanium dioxide, about 8% sulfuric acid, about 14% titanium dioxide in terms of titanium dioxide, and the rest are mud minerals, pyroxene, magnesium aluminum tips. As spar, amphibole, chlorite, olivine, quartz, pyrrhotite and pyrite, due to the low content of titanium and complex composition, it can not be directly returned to the acid hydrolysis section, and is generally deposited as solid waste. With the expansion of domestic titanium dioxide producer capacity, titanium concentrate resources are becoming more and more valuable, and random stacking not only wastes resources but also easily causes environmental pollution. The inventor's company produces 500 kilograms of acid slag per ton of titanium dioxide produced. According to the annual output of 200,000 tons of titanium dioxide, the annual acid hydrolysis slag reaches 100,000 tons, and the environmental pressure and land acquisition pressure are huge. If the titanium concentrate and soluble titanium liquid are recovered through processing, more than 17,000 tons of titanium dioxide can be recovered in one year, and the economic and social benefits are remarkable. However, due to the late start of domestic titanium dioxide production, there has been little research in this area. The foreign titanium dioxide industry has already turned to the chlorination process, and there is basically no literature report on the treatment of acid slag.

In order to develop and utilize the acid-decomposed waste residue, the former has done some work. For example, the patent of CN101469367A uses the method of water rough selection and magnetic separation to recover the titanium white acid residue. The patent document of the publication No. CN101 161353A reports a titanium sulfate method. A method of obtaining titanium concentrate by flotation by white acid dissolving waste. The above process has the following shortcomings: On the one hand, the cost of treating the waste residue by the beneficiation method is large; on the other hand, it is difficult to acidify it by normal acid hydrolysis conditions, and it is necessary to use pressurized acid hydrolysis and high concentration of concentrated sulfuric acid. In progress, this also increases the raw material cost of sulfuric acid; in addition, the titanium solution obtained by acid hydrolysis is difficult to settle, and the quality is poor, and it is not suitable to produce high-quality titanium dioxide; finally, the above method is for recovering titanium concentrate and solubility therein. The efficiency of titanium fluid is low and there is still the problem of wasting resources. Summary of the invention

In order to overcome the deficiencies of the prior art, the present invention provides a method for recycling acid slag in the production of titanium dioxide by a sulfuric acid process. The present invention employs a hydrocyclone technique to recover titanium concentrate using a difference in density of different components. In the recycling process, new impurities are not introduced, new pollution is avoided, and titanium dioxide is recovered, and soluble titanium is also recovered. After the acid hydrolysis residue is treated by the technique of the invention, the amount of slag discharged from the titanium dioxide is effectively reduced and the slag is increased. The recovery rate of titanium dioxide in the acid hydrolysis section not only saves precious mineral resources, but also reduces the stacking amount of waste residue, and has good economic and environmental benefits.

卞^ ^: Implemented by the following technical solutions:

A method for recycling acid-decomposing slag in titanium dioxide produced by a sulfuric acid method, comprising the following steps:

(1) adding water to beat the pulp: the acid-decomposing slag produced in the filter press section is sent to the beating tank and mixed with water to form a suspended solid slurry with a solid phase content of 10 to 50%, which is sent to the buffer tank for use;

(2) Separation: Separation of components of different densities using a hydrocyclone;

(3) Recovery: The material from the cyclone nozzle of the cyclone is the enriched titanium concentrate, sent to the acid hydrolysis process and sent to the acid solution pot to participate in the acid hydrolysis reaction; the overflow material is collected through the collection tank. It is sent to the subsequent pressure filtration section. The filtrate contains a large amount of titanium oxysulfate. After collection, it is sent to the acid hydrolysis section for leaching water to recover the titanium resources. The filter cake is mixed with lime and disposed of in a harmless manner.

According to the recycling method of the present invention, in the step (1), preferably, the slurry concentration is from 20% to 50% in terms of the solid phase.

More preferably, the slurry concentration is 30% to 45% based on the solid phase.

According to the recycling method of the present invention, in the step (2), the slurry in the buffer tank is sent to the cyclone by using a centrifugal pump, and the titanium ore concentrate is controlled by controlling the feed pressure of the cyclone to the overflow port. The operating pressure of the hydrocyclone is controlled between 0.10 MPa and 0.40 MPa. More preferably, the operating pressure of the hydrocyclone is controlled between 0.15 MPa and 0.25 MPa.

According to the recycling method of the present invention, the hydrocyclone has a size of 1 to 5 inches.

More preferably, the hydrocyclone has a size of 2 to 3 inches.

The titanium concentrate in the acid-decomposed slag according to the present invention is a residue which is pulverized by a ball mill and then subjected to acid hydrolysis, and has a particle diameter ranging from several micrometers to several tens of micrometers, belonging to micron-sized particles, to be precise and fast. The separation is quite sensitive to the size of the cyclone. It has been experimentally verified that it should be selected between 1 inch and 4 inches. The diameter is too small and the processing capacity is low and it is prone to blockage. The diameter is too large and the feed pressure is high, the sorting precision is lowered, and the energy loss is large. Due to the high hardness of the pulp mineral after beating and the large amount of dilute sulfuric acid, there are stringent requirements for the materials and processing of pumps, pipes and cyclones. In order to reduce the requirements on the equipment, a 2-inch cyclone is generally preferred, and a good separation accuracy is achieved with a lower operating pressure.

The raw material of the technology of the present invention is the residue of the acid hydrolysis reaction in the production process of titanium dioxide, and there is no requirement for the water quality of the beating water, and the acidic wastewater in the production process of deionized water, tap water and titanium dioxide can be used. The finally collected titanium concentrate is used as a raw material for acid hydrolysis. The filtered filtrate is also returned to the system as a leachate from the acid hydrolysis section, and the soluble titanium and dilute sulfuric acid are recovered.

The technology of the present invention processes the acid-decomposing slag, does not introduce any impurities, avoids new pollution, recovers the titanium concentrate and also recovers the soluble titanium, and after the acid-decomposing slag is treated by the technique of the invention, the slag discharging amount of the ton titanium dioxide From 500 kg to 240 kg, the recovery rate of titanium dioxide in the acid hydrolysis section increased from 91.5% to 98%, which not only saved valuable mineral resources, but also reduced the amount of waste residue, and had good economic and environmental benefits.

Specific actual 3⁄4 3⁄4T

Any feature disclosed in this specification, unless specifically stated otherwise, may be replaced by other equivalents or alternative features having similar purposes. That is, unless specifically stated, each feature is only a series of equivalents or similar An example of a feature. At the same time, the description of the alternative features in this specification is a description of equivalent technical features and should not be considered as a contribution to the public.

The invention relates to a method for recycling and utilizing acid slag in the process of producing titanium dioxide by using a sulfuric acid method, which comprises the following steps:

According to the recycling method of the present invention, in the step (2), the slurry in the buffer tank is sent to the cyclone by using a centrifugal pump, and the titanium alloy is controlled by controlling the feed pressure of the cyclone to the overflow port. The outflow of the mine shall prevail, and the operating pressure of the hydrocyclone shall be controlled between 0.10 MPa and 0.40 MPa.

More preferably, the operating pressure of the hydrocyclone is controlled between 0.15 MPa and 0.25 MPa.

More preferably, the hydrocyclone has a size of 2 to 3 inches.

The technical solutions of the present invention are further elaborated below through specific embodiments. Example 1

A method for recycling and utilizing acid slag in the process of producing titanium dioxide by sulfuric acid method, specifically including Next steps:

(1) Adding water to beat the pulp: The acid-decomposing slag produced by the filter press section is sent to the beating tank and mixed with water to form a slurry of suspended solids with a solid phase content of 10%, which is sent to the buffer tank for use;

(2) Separation: Separating components of different densities using a hydrocyclone, specifically using a centrifugal pump to feed the slurry in the buffer tank into the cyclone, by controlling the feed pressure of the cyclone to the overflow port The output of the cyclone is preferably O.10 MPa, and the size of the hydrocyclone is 1 inch;

(3) Recycling: The material from the cyclone grit nozzle is the enriched titanium concentrate, sent to the acid hydrolysis process and sent to the acid solution pot to participate in the acid hydrolysis reaction; the overflow material is collected through the collection tank. It is sent to the subsequent pressure filtration section. The filtrate contains a large amount of titanium oxysulfate. After collection, it is sent to the acid hydrolysis section for leaching water to recover the titanium resources. The filter cake is mixed with lime and disposed of in a harmless manner.

Example 2

A method for recycling acid-decomposing slag in a process for producing titanium dioxide by a sulfuric acid method, which comprises the following steps:

(1) Adding water to beat the pulp: The acid-decomposing slag produced in the filter-filtering section is transported to the beating tank to mix with the water to form a firewood, and a suspended solid slurry having a solid phase content of 50% is formed, which is sent to the buffer tank for use;

(2) Separation: Separating components of different densities using a hydrocyclone, specifically using a centrifugal pump to feed the slurry in the buffer tank into the cyclone, by controlling the feed pressure of the cyclone to the overflow port The titanium concentrate is outflow, the feed pressure of the cyclone is preferably 0.40 MPa, and the size of the hydrocyclone is 5 inches;

(3) Recycling: The material from the cyclone grit nozzle is the enriched titanium concentrate, sent to the acid hydrolysis process and sent to the acid solution pot to participate in the acid hydrolysis reaction; the overflow material is collected through the collection tank. Sent to the subsequent pressure filtration section, the filtrate contains a large amount of titanium oxysulfate, collected and sent to the acid hydrolysis section to make leaching water for recycling Titanium resources; filter cake and lime are mixed and harmlessly treated and concentrated.

Example 3

(1) Adding water to beat the pulp: The acid-decomposing slag produced by the filter press section is sent to the beating tank and mixed with water to form a slurry of suspended solids with a solid phase content of 20%, which is sent to the buffer tank for use;

(2) Separation: Separating components of different densities using a hydrocyclone, specifically using a centrifugal pump to feed the slurry in the buffer tank into the cyclone, by controlling the feed pressure of the cyclone to the overflow port The outflow of the titanium concentrate is correct, the feed pressure of the cyclone is preferably 0.15 MPa, and the size of the hydrocyclone is 2 inches;

Example 4

In Example 1, the concentration of the suspension slurry was 30% of the solid phase content, the feed pressure of the cyclone was 0.25 MPa, and the size of the hydrocyclone was 3 inches.

Example 5

In the embodiment 1, the concentration of the suspended solid slurry is 45% of the solid phase content, and the feed pressure of the cyclone is preferably 0.25 MPa, and the size of the hydrocyclone is 4 inches.

Example 6

12 tons of acid-decomposed slag after pressure filtration, add 20 cubic meters of tap water to make a paddle, then transfer to the buffer tank, keep the cyclone feed pressure 0.20MPa to feed a 2吋 diameter cyclone, after 3 hours of separation , A total of 5.8 tons of sediments were collected from the bottom flow collection tank of the cyclone. The moisture content was 25.1%, the titanium dioxide content was 38.9%, and the titanium dioxide content of the titanium concentrate was mixed with the new titanium concentrate to enter the acid solution pot. The acid hydrolysis reaction is normal. After the cyclone overflow material was filtered by the filter press, a total of 19.8 cubic meters of filtrate was collected. After analysis, the titanium content (calculated as Ti0 ₂ ) was 1.82%, and it was returned to the acid hydrolysis section for leaching water, and the use condition was normal.

Example 7

12 tons of acid-decomposed slag after pressure filtration, 20 m3 of tap water was added and beaten into a buffer tank, and the cyclone feed pressure was maintained at 0.14 MPa to feed a 1 吋 diameter cyclone. After 20 hours of separation, A total of 5.75 tons of sediments were collected from the bottom flow collection tank of the cyclone. The moisture content was 24.9%, the titanium dioxide content was 38.5%, and the titanium dioxide content of the titanium concentrate was mixed with the new titanium concentrate to enter the acid solution pot. The acid hydrolysis reaction is normal. After the cyclone overflow material was filtered by a filter press, a total of 19.4 cubic meters of filtrate was collected. After analysis, the titanium content (calculated as Ti0 ₂ ) was 1.85%, and returned to the acid hydrolysis section for leaching water, and the use condition was normal.

Example 8

12 tons of acid-decomposed slag after pressure filtration, added 20 cubic meters of tap water to be beaten, transferred to a buffer tank, and kept the cyclone feed pressure 0.60 MPa to a 4 吋 diameter cyclone feed, after 1 hour of separation, A total of 6.0 tons of sediments were collected from the cyclone bottom flow collection tank. The moisture content was 25.3%, the titanium dioxide content was 37.9%, and the titanium dioxide content of the titanium concentrate was mixed with the new titanium concentrate to enter the acid solution pot. The acid hydrolysis reaction is normal. After the cyclone overflow material was filtered by a filter press, a total of 19.0 cubic meters of filtrate was collected. After analysis, the titanium content (calculated as Ti0 ₂ ) was 1.82%, and returned to the acid hydrolysis section for leaching water, and the use condition was normal.

It is to be understood that the invention is not limited to the embodiments described above, and any modifications, equivalent substitutions and improvements made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

A method for recycling acid-decomposing slag in titanium dioxide produced by a sulfuric acid method, comprising the steps of:

(1) Adding water and beating: transferring the acid-decomposed slag generated in the filter press section to the beating tank and mixing with water to form a suspended solid slurry with a solid phase content of 10~50%, which is sent to the buffer tank for use;

(3) Recycling: The material from the cyclone nozzle of the cyclone is enriched titanium concentrate, sent to the acid hydrolysis process and sent to the acid solution pot to participate in the acid hydrolysis reaction; the overflow material is collected through the collection tank. It is sent to the subsequent pressure filtration section. The filtrate contains a large amount of titanium oxysulfate. After collection, it is sent to the acid hydrolysis section for leaching water to recover the titanium resources. The filter cake is mixed with lime and disposed of in a harmless manner.

The recycling method according to claim 1, characterized in that in the step (1), it is more preferably 20% to 50%.

3. The recycling method according to claim 1, wherein in the step (1), preferably, the slurry concentration is 30% to 45% based on the solid phase.

4. The recycling method according to claim 1, wherein in the step (2), the slurry in the buffer tank is sent to the cyclone by using a centrifugal pump, and the feed pressure of the cyclone is controlled to 5MPa之间。 Between 0. 10MPa~0. 40MPa between the pressure of the hydraulic cyclone operating pressure is controlled.

Between MPa and 0. 25Mpa, the operating pressure of the hydraulic cyclone is controlled between 0.15MPa~0. 25Mpa.

6. The recycling method according to claim 1 or 4 or 5, wherein the hydrocyclone has a size of 1 to 5 inches.

7. The recycling method according to claim 6, wherein the hydrocyclone is more preferably 2 to 3 inches in size.