CN1570160A

CN1570160A - Scheelite disassembling method

Info

Publication number: CN1570160A
Application number: CNA2004100231873A
Authority: CN
Inventors: 宋善章
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-05-13
Filing date: 2004-05-13
Publication date: 2005-01-26

Abstract

The invention relates to a method for decomposing tungsten minerals, especially for scheelite. The process comprises two steps: first autoclaving and second autoclaving, characterized in that the first autoclaving step comprises adding the scheelite and the high fluorous-containing coarse Na#-[2]WO#-[4] solution into a common stirring autoclave with the solid to liquid ratio (by weight) of 0.5-0.7, the autoclaving temperature of 160 C. to 180 C., pressure of 0.5Mpa to 0.8Mpa, keeping the temperature for 1 hour, cooling to the temperature in a range of between 70 C. and 80 C. and filtering, obtaining low fluorous-containing pure Na#-[2]WO#-[4] solution and the primary residues; the second autoclaving step comprises adding the primary residues and the NaF of 1.4 to 1.5 times that of the theoretical weight into the autoclave and autoclaving with the pressure of 0.8Mpa to 1.0Mpa and the temperature of 180 C. to 195 C., keeping the temperature for 1 hour to 1.5 hours, cooling to the temperature in a range of between 70 C. and 70 C., obtaining the high fluorous-containing coarse Na#-[2]WO#-[4].

Description

Method for decomposing scheelite

Technical Field

The invention relates to a method for decomposing tungsten ore, in particular to a method for decomposing scheelite.

Background

The chinese patent publication No. 03118385.9 discloses a method for decomposing scheelite, which is characterized in that it comprises three steps of primary pressure cooking, secondary pressure cooking and phosphoric acid recovery, wherein the primary pressure cooking step comprises finely grinding the scheelite, and then finely grinding the scheelite and high-phosphorus NaWO₄Adding the solution into a common stirring kettle, and performing pressure boiling, wherein the solid-to-liquid ratio (weight ratio) is controlled to be 0.5-1.0, pressing and boiling at 120-160 ℃, pressure of 0.1-0.5 Mpa, heat preservation time of 0.5-1 hour, cooling and discharging, cooling to 50-80 ℃, and filtering to obtain low-phosphorus Na₂WO₄Products and primary filter residue; the secondary pressure cooking step is that the filter residue after the primary pressure cooking, alkali with the theoretical amount of 1.2-1.5 times and phosphoric acid with the theoretical amount of 0.8-1.2 times are added into a pressure cooking kettle; the phosphoric acid recovery step is completed by adding concentrated sulfuric acid to the filter residue after the secondary pressure cooking for leaching.

The method has the advantages of low pressure (only 0.1-0.5 Mpa), low alkalinity, high decomposition rate, simple and easy operation, but also has H₃PO₄Or Na₃PO₄High price, resulting in high cost and poor economic efficiency.

Disclosure of Invention

The invention aims to provide a ratio H₃PO₄Or Na₃PO₄The cheaper NaF decomposition reagent is used for decomposing scheelite so as to obtain better economic benefit.

The technical solution of the invention is as follows: grinding scheelite and crude Na with high fluorine content₂WO₄Adding the solution into a common stirred autoclave for primary autoclaving to obtain refined Na with low fluorine content₂WO₄Solution and primary filter residue; adding the filter residue and NaF into a pressure boiling kettle for secondary pressure boiling to obtain crude Na with high fluorine content₂WO₄And (3) solution.

The main chemical reactions of the invention are as follows:

secondary pressure cooking and secondary pressure cooking:

the method comprises two steps of primary pressure cooking and secondary pressure cooking, and is characterized in that the primary pressure cooking step is to grind scheelite firstly, and then grind the scheelite and coarse Na with high fluorine content₂WO₄Adding the solution into a common stirring pressure boiling kettle, controlling the solid-to-liquid ratio (weight ratio) to be 0.5-0.7, the pressure boiling temperature to be 160-180 ℃, the pressure to be 0.5-0.8 Mpa, preserving the heat for 1 hour, discharging the material, cooling to 70-80 ℃, and filtering to obtain the refined Na with low fluorine₂WO₄Solution and primary filter residue; and the secondary pressure cooking step is to add the filter residue subjected to primary pressure cooking and NaF (calculated according to unreacted calcium in the filter residue) with the theoretical amount of 1.4-1.5times into the pressure cooking kettle for pressure cooking, wherein the pressure is 0.8-1.0 Mpa, the temperature is 180-195 ℃, the temperature is kept for 1-1.5 hours, discharging is carried out, the temperature is reduced to 70-80 ℃, and filtering is carried out to obtain crude Na with high fluorine content₂WO₄And (3) solution.

The scheelite is ground to-0.045 mm>91%.

The invention has the advantages that: simple and safe operation, and the decomposition reagent NaF is compared with H₃PO₄Or Na₃PO₄Cheap and has better economic benefit.

Drawings

The attached figure is a process flow diagram of the invention.

Detailed Description

The present invention and its embodiments are described in further detail below with reference to the accompanying drawings.

Example 1

1000 g of a suspension containing 67% of WO₃Grinding scheelite to-0.045 mm>91%, adding WO₃180g/l of crude Na, NaF28g/l₂WO₄Adding 2000 g of the solution into a common stirred autoclave, keeping the temperature at 160 ℃ under 0.5Mpa for 1 hour, discharging the solution, cooling to 70 ℃, filtering, and adding Na₂WO₄The content of F in the solution is reduced to below 0.12g/l, and the scheelite filter residue after primary pressure cooking contains WO₃58% by weight, adding 1.4 times the theoretical amount of NaF (calculated as unreacted calcium in the slag) under pressurePerforming secondary pressure boiling at 180 deg.C under 0.8Mpa for 1.5 hrto obtain secondary residue containing WO₃1.1% (weight percent), that is, the decomposition rate was 99.3%.

Example 2

Crude Na₂WO₄1670 g of solution, 0.7Mpa pressure of one-time pressure boiling, 170 ℃, 1 hour of heat preservation for discharging, and cooling to 8 DEG CFiltering at 0 deg.C, adding NaF 1.45 times of theoretical amount into the residue after primary pressure boiling at 0.9Mpa and 190 deg.C, and adding WO into the residue after secondary pressure boiling₃0.95% and a decomposition rate of 99.4% as in example 1.

Example 3

Crude Na₂WO₄1430 g of solution, primary pressure boiling under 0.8Mpa at 180 deg.C, heat preservation for 1 hr, secondary pressure boiling under 1.0Mpa at 195 deg.C with NaF of 1.5 times of theoretical amount, secondary residue WO₃It was 0.90%, that is, the decomposition rate was 99.5%, as in example 1.

Claims

1. A method for decomposing scheelite includes two steps of primary pressure cooking and secondary pressure cooking, and is characterized in that the primary pressure cooking step is to firstly grind the scheelite and then grind the scheelite and coarse Na with high fluorine content₂WO₄Adding the solution into a common stirring pressure boiling kettle, controlling the solid-to-liquid ratio (weight ratio) to be 0.5-0.7, the pressure boiling temperature to be 160-180 ℃, the pressure to be 0.5-0.8 Mpa, preserving the heat for 1 hour, discharging the material, cooling to 70-80 ℃, and filtering to obtain the refined Na with low fluorine₂WO₄Solution and primary filter residue; the secondary pressure cooking step is to mix the filter residue subjected to primary pressure cooking with NaF (according to WO in the primary filter residue) with the theoretical amount of 1.4-1.5 times₃Calculation) are added into a pressure boiling kettle together for pressure boiling, the pressure is 0.8-1.0 Mpa, the temperature is 180-195 ℃, the temperature is kept for 1-1.5 hours, discharging is carried out, the temperature is reduced to 70-80 ℃, and filtering is carried out, thus obtaining the crude Na with high fluorine content₂WO₄And (3) solution.

2. The method of claim 1 wherein said scheelite is ground to-0.045 mm>91%.