Electrolyte supplement system in aluminium electrolysis process and method for preparing the same

Abstract

The disclosure provides an electrolyte supplement system in an aluminum electrolysis process, which includes low-molecular-ratio cryolite, wherein the low-molecular-ratio cryolite is selected from mKF.AlF.sub.3, nNaF.AlF.sub.3 or mixture thereof, where m=11.5 and n=11.5. When the electrolyte supplement system provided by the disclosure is applied to the aluminum electrolytic industry, electrolytic temperature can be reduced obviously in the aluminum electrolysis process without changing the existing electrolytic process; thus, power consumption is reduced, volatilization loss of fluoride is reduced and the comprehensive cost of production is reduced.

Claims

1. An electrolyte supplement system in an aluminum electrolysis process, which includes low-molecular-ratio cryolite, wherein the low-molecular-ratio cryolite is a mixture of mKFAlF.sub.3 and nNaFAlF.sub.3, and the mole ratio of the mKFAlF.sub.3 to the nNaFAlF.sub.3 is 1:11.3, where m=1 or 1.2 and n=1 or 1.2.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) The disclosure is described below in further detail through specific embodiments.

Embodiment 1

(2) Weighing 1 ton of aluminium and putting it into a reactor, injecting argon to the reactor for protection after vacuumizing, heating the reactor to a temperature of 780 DEG C., adding dried potassium fluoborate in the reactor slowly in accordance with a reaction ratio and stirring quickly for 5 hours to form boron and potassium cryolite KF.AlF.sub.3, opening the cover of the reactor, pumping the superstratum melt liquid potassium cryolite KF.AlF.sub.3 through a siphon-pump.

(3) Adding the electrolyte supplement system KF.AlF.sub.3 in the aluminium electrolysis process to the electrolyte basic system consumed continuously, which can cause an obvious reduction of electrolytic temperature and finally to a temperature of between 800 and 820 DEG C. Since the corrosivity of the potassium cryolite KF.AlF.sub.3 is stronger than that of the sodium fluoroaluminate, in order to prolong the service life of the electrolytic cell, the electrolytic cell needs to adopt an inert anode or a cathode subjected to inert surface treatment.

Embodiment 2

(4) Weighing 1 ton of aluminium and putting it into a reactor, injecting argon to the reactor for protection after vacuumizing, heating the reactor to a temperature of 800 DEG C., adding dried potassium fluotitanate in the reactor slowly in accordance with a reaction ratio and stirring quickly for 5 hours to form titanium sponge and potassium cryolite 3/2KF.AlF.sub.3, opening the cover of the reactor, pumping the superstratum melt liquid potassium cryolite 3/2KF.AlF.sub.3 through a siphon-pump.

(5) Adding the electrolyte supplement system 3/2KF.AlF.sub.3 in the aluminium electrolysis process to the electrolyte basic system consumed continuously, which can cause an obvious reduction of electrolytic temperature and finally to a temperature of between 820 and 850 DEG C. Since the corrosivity of the potassium cryolite KF.AlF.sub.3 is stronger than that of the sodium fluoroaluminate, in order to prolong the service life of the electrolytic cell, the electrolytic cell needs to adopt an inert anode or a cathode subjected to inert surface treatment.

Embodiment 3

(6) Weighing 1 ton of aluminium and putting it into a reactor, injecting argon to the reactor for protection after vacuumizing, heating the reactor to a temperature of 750 DEG C., adding the mixture of dried sodium fluoborate and sodium fluotitanate in the reactor slowly in accordance with a reaction ratio, wherein the mole ratio of the sodium fluoborate to the sodium fluotitanate is 2:1; stirring quickly for 5 hours to form titanium boride and sodium cryolite 6/5NaF.AlF.sub.3, opening the cover of the reactor, pumping the superstratum melt liquid sodium cryolite 6/5NaF.AlF.sub.3 through a siphon-pump.

(7) Adding the electrolyte supplement system 6/5NaF.AlF.sub.3 in the aluminium electrolysis process to the electrolyte basic system consumed continuously, which can cause a reduction of electrolytic temperature and finally to a temperature of between 900 and 930 DEG C.

Embodiment 4

(8) Weighing 1 ton of aluminium and putting it into a reactor, injecting argon to the reactor for protection after vacuumizing, heating the reactor to a temperature of 780 DEG C., adding dried potassium fluoborate in the reactor slowly in accordance with a reaction ratio and stirring quickly for 5 hours to form boron and potassium cryolite KF.AlF.sub.3, opening the cover of the reactor, pumping the superstratum melt liquid potassium cryolite KF.AlF.sub.3 through a siphon-pump. Weighing 1 ton of aluminium and putting it into a reactor, injecting argon to the reactor for protection after vacuumizing, heating the reactor to a temperature of 750 DEG C., adding the mixture of dried sodium fluoborate and sodium fluotitanate in the reactor slowly in accordance with a reaction ratio, wherein the mole ratio of the sodium fluoborate to the sodium fluotitanate is 2:1; stirring quickly for 5 hours to form titanium boride and sodium cryolite 6/5NaF.AlF.sub.3, opening the cover of the reactor, pumping the superstratum melt liquid sodium cryolite 6/5NaF.AlF.sub.3 through a siphon-pump

(9) Mixing the obtained potassium cryolite KF.AlF.sub.3 with the obtained sodium cryolite 6/5NaF.AlF.sub.3 in a mole ratio of 1:1 and adding the mixture to the electrolyte basic system consumed continuously as the electrolyte supplement system in the aluminium electrolysis process, which can cause an obvious reduction of electrolytic temperature and finally to a temperature of between 860 and 880 DEG C. Since the corrosivity of the potassium cryolite KF.AlF.sub.3 is stronger than that of the sodium fluoroaluminate, in order to prolong the service life of the electrolytic cell, the anode and cathode of the electrolytic cell had better subject to inert surface treatment.

Embodiment 5

(10) Weighing 5 tons of aluminium and putting it into a reactor, heating the reactor to a temperature of 750 DEG C., adding 2 tons of mixture of dried potassium fluoborate and potassium fluotitanate in the reactor slowly, wherein the mole ratio of the potassium fluoborate to the potassium fluotitanate is 1:1; stirring quickly for 4 hours to form aluminium-titanium-boron alloy and potassium cryolite 9/7KF.AlF.sub.3 due to excessive aluminium, opening the cover of the reactor, pumping the superstratum melt liquid potassium cryolite 9/7KF.AlF.sub.3 through a siphon-pump. Weighing 1 ton of aluminium and putting it into a reactor, injecting argon to the reactor for protection after vacuumizing, heating the reactor to a temperature of 780 DEG C., adding dried sodium fluoborate in the reactor slowly in accordance with a reaction ratio and stirring quickly for 5 hours to form boron and sodium cryolite NaF.AlF.sub.3, opening the cover of the reactor, pumping the superstratum melt liquid sodium cryolite NaF.AlF.sub.3 through a siphon-pump.

(11) Mixing the obtained potassium cryolite 9/7KF.AlF.sub.3 with the obtained sodium cryolite NaF.AlF.sub.3 in a mole ratio of 1:1 and adding the mixture to the electrolyte basic system consumed continuously as the electrolyte supplement system in the aluminium electrolysis process, which can cause an obvious reduction of electrolytic temperature and finally to a temperature of between 850 and 880 DEG C. Since the corrosivity of the potassium cryolite 9/7KF.AlF.sub.3 is stronger than that of the sodium fluoroaluminate, in order to prolong the service life of the electrolytic cell, the anode and cathode of the electrolytic cell had better subject to inert surface treatment.

Embodiment 6

(12) Weighing 1 ton of aluminium and putting it into a reactor, injecting argon to the reactor for protection after vacuumizing, heating the reactor to a temperature of 750 DEG C., adding the mixture of dried potassium fluoborate and potassium fluotitanate in the reactor slowly in accordance with a reaction ratio, wherein the mole ratio of the potassium fluoborate to the potassium fluotitanate is 2:1; stirring quickly for 5 hours to form titanium boride and potassium cryolite 6/5KF.AlF.sub.3, opening the cover of the reactor, pumping the superstratum melt liquid potassium cryolite 6/5KF.AlF.sub.3 through a siphon-pump. Weighing 5 tons of aluminium and putting it into a reactor, heating the reactor to a temperature of 750 DEG C., adding 2 tons of mixture of dried sodium fluoborate and sodium fluotitanate in the reactor slowly, wherein the mole ratio of the sodium fluoborate to the sodium fluotitanate is 1:1; stirring quickly for 4 hours to form aluminium-titanium-boron alloy and sodium cryolite 9/7NaF.AlF.sub.3 due to excessive aluminium, opening the cover of the reactor, pumping the superstratum melt liquid sodium cryolite 9/7NaF.AlF.sub.3 through a siphon-pump.

(13) Mixing the obtained potassium cryolite 6/5KF.AlF.sub.3 with the obtained sodium cryolite 9/7NaF.AlF.sub.3 in a mole ratio of 1:3 and adding the mixture to the electrolyte basic system consumed continuously as the electrolyte supplement system in the aluminium electrolysis process, which can cause an obvious reduction of electrolytic temperature and finally to a temperature of between 870 and 890 DEG C. Since the corrosivity of the potassium cryolite 6/5KF.AlF.sub.3 is stronger than that of the sodium fluoroaluminate, in order to prolong the service life of the electrolytic cell, the anode and cathode of the electrolytic cell had better subject to inert surface treatment.

(14) The above are the further detailed description of the disclosure made in conjunction with specific preferred embodiments; it can not be considered that the specific embodiment of the disclosure is only limited to the description above. For the common technicians in the technical field of the disclosure, umpty simple deductions or substitutes can be made without departing from the concept of the disclosure and they are deemed to be included within the scope of protection of the disclosure.