CN101838750A

CN101838750A - Method for performing direct acid adjusting closed cycle on ammonium paratungstate crystallization mother liquor

Info

Publication number: CN101838750A
Application number: CN201010176912A
Authority: CN
Inventors: 李军; 熊小明; 丁伟; 谢彦; 武四平
Original assignee: GANZHOU HUAXING TUNGSTEN PRODUCTS CO Ltd
Current assignee: GANZHOU HUAXING TUNGSTEN PRODUCTS CO Ltd
Priority date: 2010-05-17
Filing date: 2010-05-17
Publication date: 2010-09-22

Abstract

The invention relates to a technique for recycling ammonium paratungstate (APT) crystallization mother liquor in the pollution-free production of tungsten wet metallurgy, in particular to a method for performing direct acid adjusting closed cycle on the ammonium paratungstate crystallization mother liquor. The method comprises the following steps of: thoroughly reducing the pH value of the APT crystallization mother liquor by using hydrochloric acid so as to separate W, P, As, Mo, Si and S2- from ammonium chloride in the APT crystallization mother liquor; and allowing the filtrate to directly return for preparing a strippant, or adding ammonia water or liquid ammonia for increasing the pH value, and then allowing the filtrate to return for preparing the strippant so as to realize the pollution-free production process for recycling the APT crystallization mother liquor. After the technique is adopted, the recovery rate of the APT production is increased by 0.5 to 1 percent, and the consumption of the ammonium chloride in the APT is reduced 100 to 150kg per ton; and the technique reduces the production cost for enterprises and improves the economic benefit.

Description

The method of the direct acid adjustment closed cycle of a kind of ammonium para-tungstate crystal mother solution

Technical field

The present invention relates to the technology of ammonium para-tungstate crystal mother solution recycle in the cleaner production of tungsten hydrometallurgy, the method for the direct acid adjustment closed cycle of particularly a kind of ammonium para-tungstate crystal mother solution.

Background technology

Ammonium paratungstate (APT) is a kind of important intermediates in the tungsten smelting process.China extensively adopts alkali decomposition-ion exchange process to produce APT at present.In this technology, carry tungsten resin NH ₄Cl and NH ₄The mixing solutions of OH carries out desorb as strippant, obtain the ammonium tungstate solution of substantially pure, adopt the selective precipitation method of Central South University's invention to remove impurity such as molybdenum, arsenic, antimony, tin afterwards, obtain purified ammonium tungstate solution, evaporative crystallization obtains product A PT afterwards, and evaporation and crystal process produces the APT crystalline mother solution.This crystalline mother solution main component is the isopoly-acid of ammonium chloride and tungsten and the ammonium salt of heteropolyacid, and pH value 6-7 contains WO usually ₃3-30g/L, Cl ^-15-70g/L, S ^2-3-15g/L, cation impurities such as anionic impurity such as a small amount of P, As, Mo, Si and Ka, Na, Ca, Mg, Cu.Since resin to the loading capacity of tungsten with Cl in the absorption feed liquid ^-The increase of concentration sharply descends, because of the APT crystalline mother solution contains higher concentration Cl ^-And can not directly return in the main flow of ion exchange process and reclaim tungsten, and the S in the crystalline mother solution ^2-Not only can cause resin poison, also can cause the peak S that parses ^2-Concentration is higher, and the APT sulphur that final crystallization goes out exceeds standard.Tungsten in the aided process recovery APT crystalline mother solution must be set in the therefore existing tungsten smelting process.

The method of existing industrial processing APT crystalline mother solution mainly contains:

A.CaCl ₂Precipitation artificial scheelite → acid decomposes and part is removed the wolframic acid of molybdenum → slightly → return main flow;

B. except that molybdenum → precipitation artificial scheelite → returning hot-bulb mill alkali decomposes;

C. secondary crystal, mother liquor redeposition artificial scheelite;

D. oxygenant desulfurization → with pressing filtering liquid mix heighten pH value → heating removal of ammonia and nitrogen → preparation and hand over before liquid.

But above-mentioned technology all exists long flow path, WO ₃The rate of recovery is low, ammonia nitrogen discharging shortcoming and crystalline mother solution NH such as exceed standard ₄Cl can not get reclaiming.

Another method that reclaims tungsten and ammonium chloride from the APT crystalline mother solution that twentieth century grows up the nineties is an ion exchange method.But shortcomings such as acid, quantity of alkali consumption are big, technology is long that this method still exists, and this method can not be removed the S in the crystalline mother solution ^2-, repeatedly finally can cause resin poison after the circulation, influence the ion-exchange operation.

Summary of the invention

The objective of the invention is for realizing short, simple, with low cost, the WO of technical process ₃Rate of recovery height reclaims crystalline mother solution NH fully ₄Cl, and the method for the direct acid adjustment closed cycle of a kind of ammonium para-tungstate crystal mother solution is provided.

Technical scheme of the present invention: the method for the direct acid adjustment closed cycle of a kind of ammonium para-tungstate crystal mother solution the steps include:

(A) APT crystalline mother solution pH value is adjusted: open in airtight steel basin and stir, add pH value≤2 of hydrochloric acid conditioning solution in the APT crystalline mother solution, H ₂S overflows the back and absorbs with the weak ammonia spray from mother liquor, treat the H in the solution ₂After the S volatilization is clean, stop to stir and clarification;

(B) filter: the precipitation in the solution that step (A) is obtained is carried out solid-liquid separation, filter residue return main flow separately or with carry out alkali after the tungsten raw materials for metallurgy mixes and decompose, filtrate can directly be returned preparation strippant or adding ammoniacal liquor and also can add and return the preparation strippant again after liquefied ammonia is heightened PH.

Step (A) is carried out at normal temperatures.

Step (A) settling time 〉=2 hours.

The ammonium sulfide solution that absorbs in the step (A) can be used as the molybdate reagent that removes of selective precipitation method; Tungsten is separated out with the form precipitation of wolframic acid, and other P few in number, As, Mo, Si impurity and Ca, Mg, Cu cationoid reaction form precipitation and separate out.

The method of step (B) solid-liquid separation is that filter cloth filters or micro-filtration.

Effect of the present invention: the present invention has made full use of S ^2-Characteristic, make it with H ₂The form of S removes from the APT crystalline mother solution, and the method that adopts hydrochloric acid to adjust pH value makes the APT crystalline mother solution directly return ion-exchange process preparation strippant, and technical process is short and simple, realizes the closed cycle of tungsten hydrometallurgy.Both reclaimed the WO in the crystalline mother solution ₃And NH ₄Cl, and the Cl of acid adjustment in the hydrochloric acid ^-, also remove the S in the crystalline mother solution ^2-Deng impurity, also reclaim H simultaneously ₂S has reduced the secondary pollution that discharge of wastewater and end treatment bring for the ammonium sulfide Returning process uses, and realizes the process for cleanly preparing that the APT crystalline mother solution reclaims.

Compare with existing mother liquor treatment process, after the employing present technique, the rate of recovery that APT produces improves 0.5%-1%, and APT ammonium chloride consumption decline 100-150kg per ton for enterprise reduces production costs, promotes economic benefit.

Embodiment

The present invention thoroughly reduces the pH value of APT crystalline mother solution to realize W, P, As, Mo, Si, S with hydrochloric acid ^2-Separate with ammonium chloride in the APT crystalline mother solution, filtrate is directly returned the preparation strippant, or adds and to return the preparation strippant again after ammoniacal liquor or liquefied ammonia are heightened PH, realizes the process for cleanly preparing that the APT crystalline mother solution reclaims.

Embodiment 1

In airtight steel basin, add crystalline mother solution 2m ³(WO ₃9.62gL ^-1, S ^2-14.92gL ^-1, P 0.038gL ^-1, As0.012gL ^-1, Mo 0.041gL ^-1, PH=7), under the normal temperature, open and stir the pH value to 1 that the back adds hydrochloric acid conditioning solution, H ₂S overflows the back and absorbs with the weak ammonia spray from mother liquor, treat the H in the solution ₂After the S volatilization is clean, stop to stir, clarification is more than 2 hours; Put into filter vat then and carry out solid-liquid separation, filtrate volume is 2.5m ³(WO wherein ₃3.21gL ^-1, S ^2-0.84gL ^-1, P 0.014gL ^-1, As 0.008gL ^-1, Mo 0.0065gL ^-1, PH=1), filtrate is directly returned the preparation strippant, realizes the closed cycle use.

WO ₃, S ^2-, P, As, Mo decreasing ratio reach 58.29%, 92.96%, 53.9%, 16.67%, 80.18% respectively.

Embodiment 2

In airtight steel basin, add crystalline mother solution 2m ³(WO ₃14gL ^-1, S ^2-11.2gL ^-1, P 0.031gL ^-1, As 0.021gL ^-1, Mo 0.037gL ^-1, PH=7), under the normal temperature, open and stir the pH value to 2 that the back adds hydrochloric acid conditioning solution, H ₂S overflows the back and absorbs with the weak ammonia spray from mother liquor, treat the H in the solution ₂After the S volatilization is clean, stop to stir, clarification is more than 2 hours; Put into filter vat then and carry out solid-liquid separation, filtrate volume is 2.3m ³(WO wherein ₃5.21gL ^-1, S ^2-1.4gL ^-1, P 0.016gL ^-1, As 0.016gL ^-1, Mo 0.008gL ^-1, PH=2), filtrate is directly returned the preparation strippant, realizes the closed cycle use.

WO ₃, S ^2-, P, As, Mo decreasing ratio reach 57.2%, 85.63%, 40.6%, 12.38%, 75.1% respectively.

Claims

1. the method for the direct acid adjustment closed cycle of ammonium para-tungstate crystal mother solution the steps include:

2. according to the method for the direct acid adjustment closed cycle of the described a kind of ammonium para-tungstate crystal mother solution of claim 1, it is characterized in that: step (A) is carried out at normal temperatures.

3. according to the method for the direct acid adjustment closed cycle of the described a kind of ammonium para-tungstate crystal mother solution of claim 1, it is characterized in that: step (A) settling time 〉=2 hours.

4. according to the method for the direct acid adjustment closed cycle of the described a kind of ammonium para-tungstate crystal mother solution of claim 1, it is characterized in that: the ammonium sulfide solution that absorbs in the step (A) can be used as the molybdate reagent that removes of selective precipitation method; Tungsten is separated out with the form precipitation of wolframic acid, and other P few in number, As, Mo, Si impurity and Ca, Mg, Cu cationoid reaction form precipitation and separate out.

5. according to the method for the direct acid adjustment closed cycle of the described a kind of ammonium para-tungstate crystal mother solution of claim 1, it is characterized in that: the method for step (B) solid-liquid separation is that filter cloth filters or micro-filtration.