CN1785805A

CN1785805A - Technology of carbon alkali method for producing borax by adding activator

Info

Publication number: CN1785805A
Application number: CN 200510200809
Authority: CN
Inventors: 吕秉玲
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-12-15
Filing date: 2005-12-15
Publication date: 2006-06-14

Abstract

The present invention relates to a technological process for producing borax by using activator-added carbon alkaline process. It is characterized by that in the solution 0.05-0.2 mol/L of diethanolamine (DEA) or methyl diethanolamine (MDEA) can be added as activator, and Na2 solid of NaHCO3,boron mineral powder and boric acid mother liquor obtained from last circulation are used, and made into slurry, then in the carbon decomposition tank the boron mineral powder can be decomposed so as to obtain the invented borax.

Description

Technology for producing borax by carbon alkali method with addition of activating agent

Technical Field

The invention belongs to the technical field of chemical engineering, and relates to a technology for producing borax by a carbon-alkali method with an added activating agent.

Background

The borax producedby the carbon-alkali method is a traditional production process and has the following defects:

(1) without using any activator to accelerate Na₂CO₃Solution absorption of CO₂The reaction speed is very slow, and the decomposition of the boron ore is generally completed within 18-22 hours. For example, in a borax plant producing 8 ten thousand tons per year, 50 carbon decomposing tanks with the diameter of 2.5 multiplied by 5.5m are required to be installed for meeting the production, and the capital cost is very high.

(2) The decomposition reaction of the boron ore can be carried out under the conditions of 130-135 ℃ and 0.6MPa pressure and continuous stirring. Stirring and heat preservation for a long time, and energy consumption is very large.

(3) When 3-4 carbon decomposition tanks work in series, CO in the tail gas discharged finally₂The concentration of (A) is more than 5%.

(4) The carbonization tank is a pressurized, heat-insulated, gas-liquid-solid three-phase reactor device with stirring function, and the capacity of a single tank is increased

The quantity difficulty is large, and the investment and the management are increased when the number of the tanks is increased.

(5) When four carbon decomposition tanks are connected in series, the tail gas discharged finally has residual pressure of 0.4MPa, and the air is discharged at present, so that the waste of compression work is caused.

Disclosure of Invention

The invention provides a borax production process by a carbon alkali method with an added activating agent, which aims to overcome the defects of the traditional production process.

The technical schemeof the invention is that Na₂CO₃Adding 0.05-0.2mol/L Diethanolamine (DEA) or Methyldiethanolamine (MDEA) as activator into the solution, and adding CO₂The absorption speed is thus increased by 10-1000 times, thereby accelerating the decomposition of the wrought boromagnesite ore. Two series carbonation towers are used, and a plurality of carbonation tanks produced by a plurality of systems in large-scale production are reduced. Each carbonating tower is 23m high, and the hydrostatic column is 20m high; the first carbonating tower through which kiln gas flows is NaHCO₃When the blockage occurs, the flow sequence of kiln gas is exchanged.

Mixing activating agent with Na₂CO₃Firstly, the solution is made in an alkali-dissolving tank and sent into a carbonating tower, and the tail gas at the outlet of a carbonating tank is carbonated to obtain NaHCO at the temperature of 60-80 DEG C₃Solid:

separating with centrifuge, and adding 10-500% of NaHCO₃Mixing the solid with boron ore powder and borax mother liquid in previous circulation to obtain slurry, and feeding into a carbonization tank with 30% CO₂The kiln gas is carbonated, and borax is generated at the temperature of 130-:

due to the use of NaHCO₃Replacing Na in the prior art₂CO₃To make CO in the liquid phase₂Increased by one time, added with NaHCO₃The excessive decomposition time of the boron ore is reduced by half, and each system only needs two carbon decomposition tanks connected in series.

The activator cannot be added with the boron ore powder so as to prevent the slag from carrying the activator away and causing loss, and the activator must be added to Na without the ore powder₂CO₃In solution.

The invention has the advantages that:

(1) because of the use of NaHCO₃The decomposition time of the boron ore in the carbonic acid tank is only 10 hours; each system only needs two carbonators connected in series. The carbonating tower does not need to stir, only keeps the reaction temperature of 60-80 ℃, and the specific heat dissipation surface of unit yield is very small, so that the borax per ton can save electricity by 60 ℃, and the heat preservation steam is more than 1 ton.

(2) The production capacity of the carbonating tower is large, two serially connected carbonating towers with the diameter of 1m can meet the requirement of annual production of 8 ten thousand of borax, and the carbonating towers are balanced in work, easy to operate and large in size. Taking a borax factory with 8 ten thousand tons of annual products as an example, the two carbonating towers replace the original 25 carbonating tanks, and the capital cost can be saved by nearly 500 ten thousand yuan.

(3) Activated by activator to absorb CO₂The speed of the reaction can be increased by 10 to 1000 times, and CO in tail gas discharged from the tower is increased₂The concentration can be reduced to below 3 percent, and CO in tail gas₂The tail gas consumption can be reduced by 5% when the tail gas consumption is reduced by 1%, and the compression cost of limestone, anthracite for calcination and kiln gas is reduced by 5%.

(4) Reduces the number of the carbon decomposing tanks, and is particularly suitable for large-scale borax production.

(5) The activator loss is very small, and the borax loss per ton is about 0.2kg.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Example (b):

containing 13.16% of B₂O₃3083kg of cooked boron-magnesium ore powder and 587kg of NaHCO from a centrifugal machine₃Mixing with borax mother liquor, introducing into a carbonization tank, and introducing CO with content of about 30%₂460m of kiln gas³Decomposing the boron ore powder, B₂O₃The decomposition rate of the catalyst reaches 90 percent. The ore pulp is sent to a filter press to filter slag, and 1000kg of borax is crystallized. Returning the borax mother liquor to the carbon decomposition tank for size mixing. The tail gas from the carbon decomposition tank contains about 21.3 percent of CO₂Entering the carbonation tower from the bottom. At the top of the carbonator, each liter of Na₂CO₃178g、NaHCO₃88g of DEA 11g of ethanol solution 2.66m³The solution out of the carbonating tower contains Na per liter₂CO₃32g、NaHCO₃99g of NaHCO and suspending the solid₃587g NaHCO from the carbonation column₃Filtering the solution, and then sending the filtered solution to a carbon decomposition tank for size mixing to be used as a raw material; NaHCO 2₃Mother liquor 2.52m³Dissolving Na₂CO₃371kg of the tail gas enters the carbonating tower continuously for carbonating, and the tail gas discharged from thecarbonating tower is 335m³In which CO is contained₂Below 3%.

Claims

1. A technology for producing borax by a carbon alkali method with addition of an activating agent is characterized by comprising the following steps:

a. adding 0.05-0.2mol/L of Diethanolamine (DEA) or Methyldiethanolamine (MDEA) as an activator into the Na2CO3 solution;

b. two carbonation towers connected in series are used, each tower is 23m high, and the height of a hydrostatic column is 20 m; exchanging the flow sequence of the kiln gas when the first carbonator tower into which the kiln gas flows first is blocked by NaHCO3 bar;

c. preparing an activating agent and Na2CO3 into a solution in an alkali dissolving tank, feeding the solution into a carbonating tower, and carbonating the solution by using tail gas at the outlet of a carbonating tank at the temperature of between 60 and 80 ℃ to prepare NaHCO3 solid; after the solid NaHCO3 is separated by a centrifugal machine, 10-50% of excessive solid NaHCO3, boron ore powder and the last circulating borax mother liquor are mixed into slurry, and the boron ore powder is decomposed in a carbon decomposition tank.