CN1210894A

CN1210894A - Producing pure tungsten compound using tungsten-containing material

Info

Publication number: CN1210894A
Application number: CN96118088A
Authority: CN
Inventors: 吴尔京; 周良益; 陈珊群
Original assignee: Central South University
Current assignee: Central South University
Priority date: 1996-04-02
Filing date: 1996-04-02
Publication date: 1999-03-17

Abstract

The method uses tungsten containing material including scheelite concentrate, high-calcium wolframite and its tailings, tungsten slime and refractory low-grade tungsten ore as material in producing tungsten compound. It features the addition of certain amount of aluminium oxide or aluminium salt and phosphate or oxides of phosphorus, 4-5 times leaching of ammonium paratungstate crystal obtained after the evaporation and crystallization of ammonium tungstate solution with 2-4% ammonium nitrate or ammonium chloride solution, and the precipitation of artificial white calcium tungstate from the ammonium paratungstate mother liquor and leaching liquor by adding ammonia water and sodium sulfide to regulate its basicity and then adding calcium chloride. The method has short technological process, high tungsten yield, low alkali consumption and no limit to P, Si and Ca contents in material and its product reaches the requirement of GB3457-820 to 0-level WO3 product.

Description

Preparation of pure tungsten compound from tungsten-containing material

The invention relates to a method for preparing a pure tungsten compound.

At present, the preparation of pure tungsten compounds by using high-calcium tungsten concentrate (calcium content is more than 3%) and tailings is generally carried out by adopting caustic soda solution decomposition method, which has less equipment investment and easily satisfied decomposition temperature requirement, but because of Ca (OH)₂The solubility in water is higher, so that the leaching rate of the high-calcium tungsten concentrate is low, and the recovery of metal tungsten is influenced. The scheelite concentrate is generally treated by a hydrochloric acid decomposition method, the decomposition rate of the scheelite concentrate is extremely low, the scheelite concentrate cannot be used for treating tailings, and the scheelite concentrate is limited in application because of more discharged gas and wastewater and serious pollution to equipment and environment. Chinese patent CN87101927A (published 9/21/1988) discloses a process for preparing ammonium paratungstate from tungsten fine mud and refractory low-grade tungsten ore, which has short process flow and is suitable forThe performance is strong, but the scheelite concentrate, the high-calcium wolframite concentrate and the tailings are difficult to process.

The invention aims to provide a method for preparing pure tungsten compounds by treating scheelite concentrate, high-calcium wolframite concentrate and tailings, tungsten fine mud and refractory low-grade tungsten ore, and simultaneously improving the recovery rate of tungsten and reducing the alkali consumption.

The method comprises the steps of wet grinding the raw materials to enable more than 98% to reach 50 mu m, adding aluminum oxide or aluminum salt accounting for 1-20% of the weight of the raw materials according to the properties of the raw materials so As to enable most of P, As and Si to remain in slag while feeding the raw materials, and adding phosphorus oxide or phosphate accounting for 1-20% of the weight of the raw materials according to the calcium content of the raw materials so As to enable calcium to generate CaPO₄And (3) adding the tungsten into the slag, converting the tungsten into soluble tungstate, adding the soluble tungstate into a solution, controlling the leaching temperature to be above 100 ℃, controlling the leaching agent to contain 350-550 g/l of NaOH, controlling the liquid-solid ratio to be 1: 0.8-1, leaching for 1.5-4 hours, and controlling the steam pressure to be more than 0.1 MPa. The main reactions are as follows:

and diluting and filtering the decomposed material, washing for 3-4 times, clarifying filtrate, evaporating, crystallizing and filtering to obtain an industrial sodium tungstate product, and supplementing alkali to the residual mother liquor after filtering to continuously use as a leaching agent. The equation for sodium tungstate crystallization is:

the conversion of sodium tungstate into ammonium tungstate is carried out by dissolving sodium tungstate crystal, filtering, diluting, clarifying, and then carrying out ion exchange, or directly carrying out ion exchange on the clear solution without crystal, wherein the alkali consumption is large under the same raw material condition, and the ion exchange reaction equation is as follows:

adding (NH) containing 80-150 g/l of sulfur₄)₂S solution in an amount of molybdenum (NH) generated from ammonium tungstate₄)₂MoS₄4-5 times of the theoretical amount of the molybdenum complex, and is used for keeping the molybdenum complex in the crystallization mother liquor and concentrating and crystallizing the ammonium tungstate. For deep purification and removal of impurities such As Mo, As, P, Si, etc., NH is further contained₄NO₃Or NH₄Leaching the solution with Cl of 2-4% for 3-4 times at 30-50 ℃, washing and drying to obtain an ammonium paratungstate product, wherein the content of elements such as calcium, molybdenum and the like in the product reaches WO₃The requirement of the GB3457-820 zero-order product is as follows:

WO 20-30 g/l of ammonium paratungstate crystallization mother liquor and washing water per liter₃The invention adopts the addition of proper amount of ammonia water to adjust the alkalinity, and NaS can be added when the molybdenum in the solution is higher₂Complexing molybdenum in it, adding CaCl₂Precipitating artificial autotungsten CaWO₄Compared with the traditional method of adding caustic soda to adjust alkalinity, the method can greatly reduce the consumption of caustic soda, and the reaction equation is as follows:

the content of the relevant elements in the raw materials of the invention generally meets the following requirements: WO₃More than 15%, Mo less than 2%, As less than 5%, and P, Si and Ca contents in the materialAnd are not limited.

The method can treat the decomposition of the scheelite concentrate, the wolframite concentrate and the tailings by using the same equipment under normal pressure and low temperature, has less equipment investment and low production cost, improves the recovery rate of the wolframite to more than 98 percent, greatly saves the using amount of alkali, and solves the problems of WO in crystallization mother liquor and washing water₃The method has the advantages of easy operation and less discharge of three wastes.

Example 1.2 tons of WO are incorporated₃Wet grinding 22% of tungsten ore raw material, 2% of Mo, 3% of As and 6% of calcium to make 98% reach below 50 μm, pumping the raw material into a decomposing pot in which NaOH with the concentration of 500g/l is previously added by a sand pump, simultaneously adding aluminium powder with the weight of 5% of the material and sodium phosphate with the weight of 6%, heating the decomposing pot by steam in a closed decomposing pot, keeping the steam pressure at 0.1MPa, stirring for 1.5-4 hours, diluting the decomposed material, pumping the diluted material into a plate-bar filter press for filtering and washing, delivering the filtrate into a clarifying tank, delivering the washing water into three washing water storage tanks with the volume of 5 cubic meters respectively for later use, using the first washing water As the dilution water of the next cycle, using the second washing water of the next cycle, using tap water for the third washing water, pumping the clarified sodium tungstate raw liquid into a crystallizing pot with the volume of 5 cubic meters respectively, concentrating and crystallizing, and filtering on a suction filter, obtaining industrial Na₂WO₄·2H₂O and crystallization mother liquor. Industrial sodium tungstate is dissolved in dissolving tank, and then filtered, diluted and clarified to obtain transformed feed liquid, and the crystallized mother liquid is supplemented with alkali and returned to the decomposition position to be used as leaching agent. The transformation feed liquid adopts the existing ion exchange process, 80 liters of ammonium sulfide of 80-150 g/l is added into the ion exchange peak liquid to remove molybdenum, and then the molybdenum is evaporated under reduced pressure in an enamel pot to obtain ammonium paratungstate, the quality of which reaches WO₃The zero-order product requirement of GB 3457-82. Adding ammonia water into the crystallization mother liquor to adjust the pH value, adding molybdenum in a sodium sulfide complex solution, and then adding CaCl at 50 DEG C₂Precipitating the artificial white tungsten CaWO₄。

Claims

1. A method for producing pure tungsten compounds by using tungsten-containing materials including scheelite concentrate, high-calcium wolframite concentrate and tailings, tungsten fine mud, refractory low-grade tungsten ore and the like as raw materials comprises the following steps of adding alumina or aluminum salt alkaline leaching with the weight of 1-20% of the raw materials, removing phosphorus, silicon and arsenic, evaporating and crystallizing sodium tungstate solution, performing ion exchange, evaporating, crystallizing and leaching ammonium paratungstate, and is characterized in that: according to the invention, phosphate or phosphorus oxide with the weight of 1-20% of that of the raw material is also added during alkaline leaching, ammonia water is added into ammonium paratungstate crystallization mother liquor and washing water to adjust the alkalinity, and calcium chloride is added to precipitate artificial white tungsten calcium tungstate.

2. The method for producing pure tungsten compounds according to claim 1, characterized in that: when ammonia water is added into ammonium paratungstate crystallization mother liquor and washing water to adjust the alkalinity, sodium sulfide can be added to complex molybdenum in the ammonium paratungstate crystallization mother liquor and the washing water.