Potassium cryolite for aluminum electrolysis industry and preparation method thereof

Abstract

The invention provides a potassium cryolite for aluminum electrolysis industry, which has a molecular formula: mKF.AlF.sub.3, wherein m is from 1 to 1.5. The low-molecular-ratio potassium cryolite (mKF.AlF.sub.3, and m is from 1 to 1.5) provided by the invention is used for aluminum electrolysis industry, and can improve the dissolvability of aluminum oxide, thus reducing the temperature of electrolysis and the consumption of power, raising the efficiency of electrolysis and lowering the comprehensive production cost.

Claims

1. A method of producing potassium cryolite comprising: weighing a quantity of aluminum; placing the weighed aluminum in a closed reactor; evacuating the closed reactor; feeding argon into the reactor after evacuation; heating the reactor to 780-850? C.; adding only dry potassium fluoborate to form a balanced mixture of aluminum and potassium fluoborate; generating only boron and potassium cryolite having a chemical formula KF.AlF.sub.3 wherein the balanced mixture reacts according to formula KBF.sub.4+Al?B+KF.AlF.sub.3 while stirring the balanced mixture in the reactor; opening a cover of the reactor; and sucking out liquid-state potassium cryolite at an upper layer of the reactor by a siphon pump.

2. The method of claim 1, wherein stirring is processed for 4 or 5 hours.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) Further detailed description is made to the invention with reference to the embodiments below.

(2) Embodiment 1

(3) 1 ton of aluminum is weighed and put in a reactor that is a closed container, argon is fed into the reactor for the purpose of protection after evacuation, the reactor is heated up to 800? C. and then slowly added with dry potassium fluotitanate based on a reaction proportion, sponge titanium and potassium cryolite) (3/2KF.AlF.sub.3) are generated after the mixture in the reactor is rapidly stirred for 5 hours, the cover of the reactor is opened and liquid-state potassium cryolite molten at the upper layer is sucked out by a siphon pump.

(4) The potassium cryolite (3/2KF.AlF.sub.3) prepared is used for aluminum electrolysis industry, the electrolyte system consists of potassium cryolite and aluminum oxide, the temperature for electrolysis can be controlled within a working range from 750? C. to 850? C. by using the electrolyte consisting of the potassium cryolite (3/2KF.AlF.sub.3) provided by the invention, and primary aluminum can be obtained by using inert electrode material, carbon electrode material or mixed (co-use of carbon electrode material and inert electrode material) electrode material for electrolysis.

(5) Embodiment 2

(6) 1 ton of aluminum is weighed and put in a reactor that is a closed container, argon is fed into the reactor for the purpose of protection after evacuation, the reactor is heated up to 780? C. and then slowly added with dry potassium fluoborate based on a reaction proportion, boron and potassium cryolite (KF.AlF3) are generated after the mixture in the reactor is rapidly stirred for 5 hours, the cover of the reactor is opened and liquid-state potassium cryolite molten at the upper layer is sucked out by a siphon pump.

(7) The potassium cryolite (KF.AlF3) prepared is used for aluminum electrolysis industry, the electrolyte system consists of potassium cryolite and aluminum oxide, the temperature for electrolysis can be controlled within a working range from 750? C. to 850? C. by using the electrolyte consisting of the potassium cryolite (KF.AlF3) provided by the invention, and primary aluminum can be obtained by using inert electrode material, carbon electrode material or mixed (co-use of carbon electrode material and inert electrode material) electrode material for electrolysis.

(8) Embodiment 3

(9) 1 ton of aluminum is weighed and put in a reactor that is a closed container, argon is fed into the reactor for the purpose of protection after evacuation, the reactor is heated up to 750? C. and then slowly added with dry mixture of potassium fluoborate and potassium fluotitanate based on a reaction proportion, the molar ratio of potassium fluoborate to potassium fluotitanate is 2:1, titanium boride and potassium cryolite (6/5KF.AlF.sub.3) are generated after the mixture in the reactor is rapidly stirred for 5 hours, the cover of the reactor is opened and liquid-state potassium cryolite molten at the upper layer is sucked out by a siphon pump.

(10) The potassium cryolite (6/5KF.AlF.sub.3) prepared is used for aluminum electrolysis industry, the electrolyte system consists of potassium cryolite and aluminum oxide, the temperature for electrolysis can be controlled within a working range from 750? C. to 850? C. by using the electrolyte consisting of the potassium cryolite (6/5KF.AlF.sub.3) provided by the invention, and primary aluminum can be obtained by using inert electrode material, carbon electrode material or mixed (co-use of carbon electrode material and inert electrode material) electrode material for electrolysis.

(11) Embodiment 4

(12) 5 tons of aluminum is weighed and put in a reactor, the reactor is heated up to 750? C. and then slowly added with 2 tons of dry mixture of potassium fluoborate and potassium fluotitanate, the molar ratio of potassium fluoborate to potassium fluotitanate is 1:1, aluminum-titanium-boron alloy and potassium cryolite (9/7KF.AlF.sub.3) are generated due to excessive amount of aluminum after the mixture in the reactor is rapidly stirred for 4 hours, the cover of the reactor is opened and liquid-state potassium cryolite molten at the upper layer is sucked out by a siphon pump.

(13) The potassium cryolite (9/7KF.AlF.sub.3) prepared is used for aluminum electrolysis industry, the electrolyte system consists of potassium cryolite and aluminum oxide, the temperature for electrolysis can be controlled within a working range from 750? C. to 850? C. by using the electrolyte consisting of the potassium cryolite (9/7KF.AlF.sub.3)provided by the invention, and primary aluminum can be obtained by using inert electrode material, carbon electrode material or mixed (co-use of carbon electrode material and inert electrode material) electrode material for electrolysis.

(14) The content discussed above is merely for further detailed description of the invention with reference to the preferred embodiments, and it shall not be considered that the embodiments of the invention are limited to the description only. Many simple deductions or substitutions could be made without departing from the concept of the invention by ordinary skilled in the art to which the invention pertains, and shall be contemplated as being within the scope of the invention.