CN102092687A - A method for producing zinc dithionite with sodium hydrosulfite filter residue - Google Patents

Abstract

The invention provides a method for producing zinc hydrosulfite by using sodium hydrosulfite filter residues, which comprises the following steps of heating sodium hydrosulfite waste residues in a rotary furnace at a high temperature of 300 ℃ to enable zinc hydroxide to start a dehydration reaction to obtain granular zinc oxide; meanwhile, zinc sulfate in the sodium hydrosulfite waste residue is decomposed into zinc oxide and sulfur dioxide gas; putting zinc oxide and coke into an electric arc furnace, and heating to 1300-1400 ℃ to obtain zinc vapor; condensing and collecting zinc vapor to obtain zinc powder; zinc powder, water and alcohol are prepared into suspension, and the suspension and sulfur dioxide are subjected to a vulcanization reaction to obtain slurry of zinc hydrosulfite crystals; washing the slurry of the zinc dithionite crystal with denatured methanol-containing alcohol, and drying in vacuum at the temperature of less than 70 ℃ to obtain a finished product of the zinc dithionite.

Description

A method for producing zinc dithionite with sodium hydrosulfite filter residue

technical field

The invention relates to the technical field of treatment and utilization of sodium hydrosulfite filter residue, in particular to a method for producing zinc dithionite with sodium hydrosulfite filter residue.

Background technique

Sodium Hydrosulfite is commonly known as Sodium Hydrosulfite. It is a strong reducing agent and is widely used in textile, printing and dyeing industries as dyeing aids and bleaching agents. It is also a raw material for synthetic dyes in the pharmaceutical industry and is also used in copper plates. Printing and analysis reagents, etc.

In recent years, the market demand for hydrosulfite has become increasingly strong and growing rapidly. In particular, the demand for hydrosulfite in the textile and printing and dyeing industries has risen steadily, with an increase of 10-15% every year. In addition, with the production and development of domestic high-end newsprint and the improvement of the quality of kaolin, this potential hydrosulfite market has gradually become prominent, and the market potential is also increasing rapidly. At present, the total amount of international hydrosulfite consumption is 500,000 tons/year; my country's export volume in 2007 was 80,000 to 100,000 tons/year; the export volume in 2008 was 120,000 to 150,000 tons; The volume has increased significantly, and it is the world's largest exporter of sodium bicarbonate. The domestic consumption is about 200,000 to 250,000 tons per year.

The production methods of hydrosulfite mainly include zinc powder method, sodium formate method and amalgam method. At present, the first two are mainly used in industry. Among them, the three wastes treatment and labor protection requirements of the sodium amalgam production process are relatively strict, and the power consumption is relatively high, so it is rarely used in industry. Sodium formate method has mature production technology, short process and less waste water, but the product has low purity and poor stability; while zinc powder method has mature production technology, high product purity and good stability, and is the main production method used in the industry .

The production of hydrosulfite by the zinc powder method is to use sulfur dioxide gas with a purity of more than 99% to treat the zinc powder suspension aqueous solution to form a zinc dithionite solution, and then add sodium hydroxide to carry out a double decomposition reaction to form sodium dithionite and zinc hydroxide. Precipitate, filter After separation, a waste residue containing sodium dithionite and zinc hydroxide precipitate is obtained. The filtrate was salted out with concentrated brine, and then filtered, separated and dehydrated, washed with ethanol and dried to obtain sodium dithionite. Therefore, the production process of hydrosulfite discharges a large amount of filter cake waste residue containing zinc hydroxide through press filtration. Zinc hydroxide waste slag is a strong alkaline substance. If it is not treated, it will cause serious corrosion and alkaline solidification to the land, especially the white dust blown by the wind is suffocating. At present, the commonly used treatment method is to use zinc hydroxide waste residue to produce zinc oxide or metal zinc for recycling. Its use is relatively single, far from being able to consume the zinc powder waste residue that increases day by day along with the increase of sodium hydrosulfite production.

Zinc dithionite is used as a bleaching agent for wood, pulp, fabric, hemp, vegetable oil, clay, kaolin and animal glue, as a beneficiation agent in the mining industry, and for the treatment of sugar beet and sucrose solutions. Industrial raw materials.

Contents of the invention

The object of the present invention is to provide a method for producing zinc dithionite with sodium hydrosulfite filter residue, which can turn waste into treasure and effectively convert zinc hydroxide in sodium hydrosulfite filter residue into dithionite with greater economic significance. Zinc sulfite fully taps and utilizes the potential economic value of hydrosulfite filter residue, and also provides a new way for the comprehensive utilization and treatment of hydrosulfite filter residue.

Technical scheme of the present invention is as follows: a kind of method of producing zinc dithionite with hydrosulfate filter residue, comprises following concrete steps:

Step A: Convert the zinc hydroxide content in the sodium hydrosulfite waste residue, after crushing, heat to 300°C in the rotary furnace (1), at this time the zinc hydroxide starts dehydration reaction, and the zinc hydroxide in the hydrosulfite waste residue is calcined into granular Zinc oxide; at the same time, the zinc sulfate in the hydrosulfite waste residue decomposes into zinc oxide and sulfur dioxide gas to escape, so as to achieve the purpose of desulfurization;

Step B: Put the zinc oxide and coke obtained in step A into the electric arc furnace (2) according to the pure mass ratio of 1:0.10-0.20, heat to 1300-1400°C, react zinc oxide and carbon monoxide to obtain carbon dioxide gas and zinc vapor ;

Step C: condensing the zinc vapor obtained in step B into zinc powder through three series-connected condensers (3), and falling into the zinc powder collector (4) to obtain zinc powder;

Step D: the zinc powder obtained in step C, water and alcohol are made into a suspension in the reactor (5), stirred continuously, and then sulfur dioxide is fed into sulfur dioxide with a pure mass ratio of 1: 0.78-1.18 for vulcanization reaction, and the reaction temperature is Control at 35-45°C to obtain a slurry of zinc dithionite crystals;

Step E: The slurry of zinc dithionite crystals obtained in step D is washed in a washing machine (6) with denatured methanol-containing alcohol, and then vacuumed in a vacuum dryer (7) at a state of less than 70° C. After drying, the zinc dithionite product (8) was obtained.

The zinc powder described in the step C is the qualified zinc powder whose residue on an 80-mesh sieve is zero and contains more than 85% zinc.

The sulfur dioxide gas obtained in step A is passed into the suspension in the reactor described in step D to carry out chemical reaction.

The carbon dioxide obtained in step B reacts chemically with C in the coke powder to obtain carbon monoxide for recycling.

The chemical reaction principle of the present invention is

Zn(OH) ₂ =====ZnO+H ₂ O

2ZnSO ₄ ＝＝＝＝＝2ZnO+2SO ₂ +O ₂

ZnO+CO=====Zn+CO ₂

CO ₂ +C======2CO

SO ₂ +H ₂ O=====H ₂ SO ₃

Zn+2H ₂ SO ₃ ＝＝＝＝＝ZnS ₂ O ₄ +2H ₂ O

The beneficial effect of the present invention is: the method for producing zinc dithionite with hydrosulfite filter residue described in the present invention, this method turns waste into treasure, effectively converts the zinc hydroxide in the hydrosulfite filter residue into the zinc hydroxide with greater economic significance Zinc dithionite fully taps and utilizes the potential economic value of hydrosulfite filter residue, and also provides a new way for the comprehensive utilization and treatment of hydrosulfite filter residue. In addition, the method has a high raw material utilization rate and produces very little waste, and is a very economical and effective method.

Description of drawings

Fig. 1 is the process flow diagram of the method for producing zinc dithionite with hydrosulfate filter residue of the present invention, wherein, (1)---rotary furnace, (2)---electric arc furnace, (3)---condenser, (4)--collector, (5)--reactor, (6)--washing machine, (7)--dryer, (8)--finished product of zinc dithionite.

Detailed ways

Example 1

With reference to Fig. 1, a kind of method of producing zinc dithionite with sodium hydrosulfite filter residue, weighing hydrosulfite 495kg, conversion zinc hydroxide content is 297kg in the sodium hydrosulfite waste residue, after pulverizing, in rotary kiln (1) high temperature is heated to 300 At this moment, zinc hydroxide starts dehydration reaction, and the zinc hydroxide in the sodium hydrosulfite waste residue is calcined into granular zinc oxide; meanwhile, the pure substance content of the zinc sulfate in the sodium hydrosulfite waste residue in 495kg hydrosulfite is 9.66kg , decomposed into zinc oxide and sulfur dioxide gas, so as to achieve the purpose of desulfurization; put the obtained zinc oxide and coke into the electric arc furnace (2) according to the pure mass ratio of 1:0.15, heat to 1300-1400 ° C, zinc oxide and carbon monoxide react to obtain carbon dioxide gas and zinc vapor; the zinc vapor is condensed into zinc powder through three series-connected condensers (3), and falls into the collector (4) of zinc powder to obtain zinc powder; the zinc powder is mixed with water and alcohol in Suspension is made into the reactor (5), stirred continuously, and then sulfur dioxide is introduced into sulfur dioxide with a pure mass ratio of zinc powder and sulfur dioxide of 1:0.98 for vulcanization reaction, and the reaction temperature is controlled at 35-45° C. to obtain zinc dithionite Crystallized slurry; the obtained slurry of zinc dithionite crystals is washed in a washing machine (6) with denatured methanol-containing alcohol, and then carried out in a vacuum dryer (7) at a state of less than 70°C Vacuum-dried to obtain the zinc dithionite finished product (8), the pure substance quality of zinc dithionite contained in it was 590.58kg.

Example 2

With reference to Fig. 1, a kind of method of producing zinc dithionite with sodium hydrosulfite filter residue, weighing hydrosulfite 495kg, conversion zinc hydroxide content is 297kg in the sodium hydrosulfite waste residue, after pulverizing, in rotary kiln (1) high temperature is heated to 300 At this moment, the zinc hydroxide starts dehydration reaction, and the zinc hydroxide in the sodium hydrosulfite waste residue is calcined into granular zinc oxide; meanwhile, the pure substance content of the zinc sulfate in the sodium hydrosulfite waste residue in 500kg hydrosulfite is 9.66kg , decomposed into zinc oxide and sulfur dioxide gas, so as to achieve the purpose of desulfurization; put the obtained zinc oxide and coke into the electric arc furnace (2) according to the pure mass ratio of 1:0.1, heat to 1300-1400 ° C, zinc oxide and carbon monoxide react to obtain carbon dioxide gas and zinc vapor; the zinc vapor is condensed into zinc powder by three series-connected condensers (3), and falls into the collector (4) of zinc powder to obtain 80 mesh sieves, and the residue is zero and contains 85% zinc. Qualified zinc powder more than %; Zinc powder and water and alcohol are made into suspension in reactor (5), keep stirring, then pass into the sulfur dioxide gas of aforementioned gain with pure mass ratio 1: 0.78 and carry out vulcanization reaction, reaction Temperature is controlled at 35-45 ℃, obtains the slurry of zinc dithionite crystallization; The slurry of gained zinc dithionite crystallization is washed in washing machine (6) with denatured alcohol containing methanol, then in vacuum Vacuum drying is carried out in the drier (7) at less than 70° C. to obtain the zinc dithionite finished product (8), which contains 310.89 kg of pure zinc dithionite.

Example 3

With reference to Fig. 1, a kind of method of producing zinc dithionite with sodium hydrosulfite filter residue, weighing hydrosulfite 495kg, conversion zinc hydroxide content is 297kg in the sodium hydrosulfite waste residue, after pulverizing, in rotary kiln (1) high temperature is heated to 300 At this moment, zinc hydroxide starts dehydration reaction, and the zinc hydroxide in the sodium hydrosulfite waste residue is calcined into granular zinc oxide; meanwhile, the pure substance content of the zinc sulfate in the sodium hydrosulfite waste residue in 495kg hydrosulfite is 9.66kg , decomposed into zinc oxide and sulfur dioxide gas, so as to achieve the purpose of desulfurization; put the obtained zinc oxide and coke into the electric arc furnace (2) according to the pure mass ratio of 1:0.20, heat to 1300-1400 ° C, zinc oxide and carbon monoxide reaction to obtain carbon dioxide gas and zinc vapor; carbon dioxide reacts chemically with C in coke powder to obtain carbon monoxide for recycling; zinc vapor is condensed into zinc powder through three series-connected condensers (3), and falls into the zinc powder Obtaining 80 mesh sieve residues in collector (4) is the qualified zinc powder that zero zinc is more than 85%; Zinc powder and water and alcohol are made into suspension in reactor (5), constantly stir, then The sulfur dioxide gas obtained above is passed into the sulfur dioxide gas at a pure mass ratio of 1:1.18 to carry out the vulcanization reaction, and the reaction temperature is controlled at 35-45 ° C to obtain a slurry of zinc dithionite crystals; the obtained slurry of zinc dithionite crystals Wash with denatured methanol-containing alcohol in a washing machine (6), and then vacuum-dry in a vacuum dryer (7) at a temperature of less than 70°C to obtain a finished product of zinc dithionite (8), which contains dithionite The pure substance mass of zinc disulfite is 590.58kg.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, its architecture can be flexible and changeable, and a series of methods can be derived. Just making some simple deductions or replacements should be deemed to belong to the patent protection scope of the present invention determined by the submitted claims.

Claims (3)

1. a method of producing zinc dithionite with the vat powder waste residue is characterized in that, comprises following concrete steps:

Steps A: zinc hydroxide content in the conversion vat powder waste residue, after the pulverizing, in rotary kiln (1) heat to 300 ℃, this moment, zinc hydroxide began dehydration reaction, and the zinc hydroxide calcining in the vat powder waste residue is granular zinc oxide; Simultaneously, the zinc sulfate in the vat powder waste residue resolves into zinc oxide and sulfur dioxide gas effusion;

Step B: the zinc oxide that steps A obtains is put into electric arc furnace (2) lining with coke according to pure mass ratio 1: 0.10-0.20, be heated to 1300-1400 ℃, zinc oxide and reaction of carbon monoxide obtain carbon dioxide and zinc fume;

Step C: step B gained zinc fume is condensed into zinc powder by three placed in-line condensers (3), and the collector (4) that falls into zinc powder obtains zinc powder;

Step D: with the zinc powder of step C gained, in reactor (5), be made into suspension with water and alcohol, the stirring that does not stop, feed sulfurous gas with pure mass ratio 1: 0.78-1.18 then and carry out vulcanization reaction, temperature of reaction is controlled at 35-45 ℃, obtains zinc dithionite crystalline soup compound;

Step e: the zinc dithionite crystalline soup compound of step D gained contains methyl alcohol with sex change alcohol washs in washing machine (6), then carries out vacuum-drying under less than 70 ℃ state in Vacuumdrier (7), obtains zinc dithionite finished product (8).

2. method of producing zinc dithionite with the vat powder waste residue as claimed in claim 1 is characterized in that, the described zinc powder of step C is that 80 screen residues are that zero to contain zinc be qualified zinc powder more than 85%.

3. method of producing zinc dithionite with the vat powder waste residue as claimed in claim 1 is characterized in that, carries out chemical reaction in the suspension in the described reactor of sulfur dioxide gas feeding step D that steps A obtains.