Method for processing molybdenum raw materials
The invention relates to hydrometallurgy, in particular to the processing of molybdenum concentrates and waste. The technical result is the development of a method for processing molybdenum raw materials that reduce the loss of valuable rare metals and the reduction of the technological scheme of processing. Method for processing molybdenum raw material includes oxidative Stripping, filtering and cleaning solution of molybdenum from heavy metals. The last carried out by contacting the solution with a macroporous vinyl-pyridine sorbent for 7-9 hours at a pH of 0.8-1.2.
The invention relates to hydrometallurgy molybdenum? in particular to the processing of molybdenum concentrates and waste.
There are two basic ways of processing molybdenum raw materials.
Widely used in industrial practice, the method for processing molybdenum raw materials, including oxidative roasting, leaching the calcine with aqueous ammonia, filtration and purification of a solution of molybdenum impurities of heavy metals. In this way the purification of solutions of molybdenum from iron, copper, and other produce precipitation in the form of their sulfides, adding to the original amiov contains significant amounts of molybdenum and rhenium, want to displacing additional technological scheme (Zelikman A. N. Metallurgy of refractory rare metals. - M.: metallurgy, 1986, S. 94-128).
The use of additional technological scheme leads to a significant loss of molybdenum and increases the production cycle.
Known hydrometallurgical methods of decomposition of molybdenum raw materials in alkaline and acidic media in the presence of an oxidising agent and complexing agents. One of such ways molybdenum raw material is subjected to the decomposition of nitric acid and conduct filtering. The precipitate molybdenum acid direct dissolution in ammonia water, and the mother liquor is on the additional extraction of molybdenum. This uterine nitric acid solution is neutralized to pH 8-9 ammonia water. While all of the iron and partly molybdenum transition from soluble to precipitate ferromolybdenum. After filtering, the precipitate is warehoused, because there is no effective technology of its processing, or used for secondary purposes. And the mother liquor containing heavy metals and molybdenum, is directed to the additional extraction of molybdenum.
After dissolving the precipitate molybdenum acid together with the rest of neerslag the Yong, rhenium and impurities are sent to purification from heavy metals. Sludge is sent for re-opening and the additional extraction of molybdenum (A. N. Zelikman metallurgy of refractory rare metals. - M.: metallurgy, 1986, S. 129-141).
In addition, when the method of decomposition of the molybdenum-containing material by leaching to the fullest translation of molybdenum in soluble form specially introduced into the pulp salts of heavy metals for the formation of a molybdenum-iron and molybdenum-copper heterocomplexes (and.with. 387600, MCP 22 IN 49/00, 1973). Introduced impurity of these metals must also be removed from the process.
When the method of decomposition of the molybdenum-containing raw materials (concentrates and metal waste) decomposition of nitric acid iron impurities are removed from the technological scheme in the form of precipitates ferromolybdenum, processing which is carried out on a very complex technological scheme with large losses of molybdenum.
The closest technical solution is a method for processing molybdenum concentrates, including oxidative Stripping, filtering, and contacting the resulting solution of molybdenum with macroporous vinyl-pyridine sorbent with perehod. EN 2017845, IPC WITH 22 34/34, 15.08.1994).
This method provides a multi-stage and duration of the processing of molybdenum raw materials, which lead to additional losses of molybdenum, and required additional surgery for removal of heavy metals, which must be entered in the technological scheme.
The present invention is to develop a method for processing molybdenum raw materials, provide technical result increased extraction of molybdenum, improving the quality of the cleaning solution of molybdenum impurities of heavy metals and the reduction of the technological scheme of processing.
The technical result is achieved due to the fact that in the method for processing molybdenum raw materials, including oxidative Stripping, filtration, contacting the resulting solution of molybdenum with macroporous vinyl-pyridine sorbent with the transition of molybdenum in phase sorbent, the washing of the sorbent and desorption of molybdenum alkaline reagent, according to the invention contacting the sorbent is carried out for 7-9 hours at a pH of 0.8-1.2 when cleaning the molybdenum from the impurities of heavy metals.
Raw materials - molybdenum concentrate or p is jut solutions containing Mo, and heavy metals such as Fe, Cu, Ni, etc. and the precipitate, which is sent to the dump. A solution of molybdenum is neutralized to a pH of 0.8-1.2 and clear of impurities of heavy metals.
Cleaning is performed by contacting the solution with a macroporous vinyl-pyridine sorbent for 7-9 hours. Used sorbents are weakly basic anion exchange resin type EAP - 1P having a macroporous structure, which as ionic groups include pyridine nitrogen. The advantage of anion exchange resins is that they allow not only to separate molybdenum and impurities of heavy metals, but also to carry out the conversion of the salts of molybdenum in need of ammonium molybdate (NH4)2MoO4from which to obtain marketable products: paramolybdate ammonium or oxide of molybdenum.
Separation of molybdenum and heavy metals in the solution is at a pH of 0.8-1.2. In conditions in solutions containing molybdenum-iron and molybdenum-copper heterocomplex [H3F6ABOUT21] and [H4Simo6ABOUT21], is their destruction and transition of iron in FeSO4, copper - CuSO4i.e., in cationic form, which the anion does not are sorbed, and molybdenum [Mo7O6-21] prehodnoceni product.
If the solution has a pH less than 0.8 or more than 1.2, molybdenum-iron and molybdenum-copper heterocomplex not indestructible in a highly acidic environment and remain in solution.
The cleaning solution of the molybdenum contact with the adsorbent is carried out for 7-9 hours. The impurities of heavy metals (Fe, Cu, Ni and others) remain in solution, and molybdenum goes into the sorbent. When cleaning solution by contacting the sorbent is less than 7 hours not all molybdenum time to move to phase sorbent, and cleaning takes more than 9 hours is impractical, because the solution is almost only contains heavy metals and then sent for recycling. And the sorbent is directed to the extraction of molybdenum. Re-opening of sediment and extract molybdenum in the proposed process, which allows to reduce the loss of valuable metals and to reduce the technological scheme of the process.
Example 1. The solution polymolybdates sodium was obtained from roasted molybdenum concentrate on THE 48-19-354-82 by leaching of the latter with sodium carbonate at pH 3-4 (known technology). The amount of solution and 150 ml of the Solution was acidified to a pH of 0.8-1.2 sulfuric acid (GOST 4204-77) on rn is (g/l): Mo 115; Fe was 2.76; si - 1,31 at pH 0.87 in static conditions was purified by contact with 10 g of macroporous sorbent brand VP-1P granulation class A (0,63-1.6 mm), produced by OST 95.291-75, THE 95.329-77, within 7 hours. Got the capacity of the sorbent (mg/g: Mo 493; Fe 24,1; C to 8.7. The sorbent was washed with water in an amount of 2 volumes 1 volume of the sorbent. The result was the content of impurities in the sorbent (mg/g): Fe - 0,6; C - not found.
A solution containing heavy metals, after washing, was sent for recycling, and the sorbent for the extraction of molybdenum. After treatment of the sorbent 3 volumes of a solution of 8% ammonia (TU 6-09-3282-73) in solution was (g/l): Mo - 114,77; si and Fe is not detected. Thus removing the Mo 99.8%. The residual capacity of the sorbent (mg/g: Mo 12; Fe 0,6; si no. Thus, there is a practically complete separation of molybdenum and heavy metals.
Example 2. Molybdenum-containing solution was obtained after dissection of molybdenum concentrate according to GOST 212-76 nitric acid according to GOST 4461-77 in the presence of oxidant - technical oxygen (95% O2) if T:W=1:4 and t=90-100°C for 4 hours in the apparatus with mechanical stirring, after final filtration on a filter press solution was neutralized to a pH of 0.8 - 1,e 1,34; Si 1,2, purified by contact with the sorbent brand VP-1P granulation class A (0,63-1.6 mm) OST 95.291-75, THE 95.327-77 in SO-24- form. Weight of 10 g sorbent, solution volume of 500 ml, the duration of cleaning contact with the sorbent 9 hours. The capacity of the sorbent was (mg/g): Mo - 264; Fe and si chemical analysis not found. In the extract solution, which is sent for recycling, the chemical analysis of the found content, g/l: Mo 0,03; Fe 1,3; C 1,2. The molybdenum from the sorbent was removed in the same way as in example 1. Extraction of molybdenum 99.7 per cent.
Thus, the proposed solution provides a reduction of well-known operations of the technological cycle by eliminating the repeated operations of opening and cleaning of impurities of heavy metals of the main technological solution. The establishment of continuous production the possibility of automation of processes, replacement of hard physical labour. This reduces the cost of raw materials, basic and auxiliary materials (mainly chemicals), increases the extraction of molybdenum up to 97-99% depending on the technology selected for processing molybdenum concentrates. Furthermore, the reduced amount of harmful substances, molybdenum raw materials, including oxidative Stripping, filtration, contacting the resulting solution of molybdenum with macroporous vinyl-pyridine sorbent with the transition of molybdenum in phase sorbent, the washing of the sorbent and desorption of molybdenum alkaline reagent, characterized in that the contact with the sorbent is carried out for 7-9 hours at a pH of 0.8-1.2, when cleaning the molybdenum from the impurities of heavy metals.
SUBSTANCE: invention relates to sorption-mediated recovery of molybdenum from solutions containing heavy metal cations. Method of invention comprises providing solution to be treated, sorption of molybdenum(VI) on anionite at pH < 7. Sorption is conducted from solutions with anionites AM-2b and AMP at solution pH below pH of hydrolytic precipitation of heavy metal cations but higher than pH of formation of molybdenum cations (pH ~ 1).
EFFECT: increased process selectivity and reduced number of stages in preparation of pure molybdenum.
9 dwg, 3 tbl, 4 ex