CN1365949A - Process for preparing Mn3O4 - Google Patents

Abstract

A process for preparing Mn3O4 includes such steps as adding diluted ammonia solution to the solution of manganese sulfate while controlling the final pH value to obtain Mn(OH)2 deposit, separating, drying, calcining, cooling, washing with water and drying again. Its advantages include high washing efficiency and high Mn recovering rate.

Description

A kind of manufacture method of trimanganese tetroxide

The present invention relates to a kind of manufacture method of trimanganese tetroxide.

Trimanganese tetroxide is that electronic industry is produced one of ferritic important source material of soft magnetism Mn-Zn, and China is to the rare bibliographical information of the research of trimanganese tetroxide, and mostly the trimanganese tetroxide of market sale now is with the electrolytic metal Mn to be raw material, the product purity height, but cost is also high.Though the oxide compound of manganese, oxyhydroxide, vitriol, carbonate, sulphite, nitrate etc. in air calcination to about 1000 ℃ the time, all can generate trimanganese tetroxide, but sulphate decomposition temperature height, decompose down not exclusively at 1000 ℃, and vitriol, sulphite, nitrate produces the corrodibility toxic gas when decomposing, very harmful to environment, equipment.During preparation carbonate, must remove the Ca in the raw material earlier ²⁺, Mg ²⁺In alkaline-earth metal, otherwise these impurity will take in the finished product trimanganese tetroxide, and remove the manufacturing cost that impurity can improve trimanganese tetroxide.The most cheap and easy to getly in the oxide compound of manganese will count electrolytic manganese dioxide, but its particle is thick, alkaline-earth metal and silicon-dioxide impurity are many, also should not be used for making high-quality trimanganese tetroxide.

The objective of the invention is to provide a kind of manufacture method of trimanganese tetroxide.

The objective of the invention is to realize by the following method: with technical grade MnSO ₄H ₂O dissolving, leave standstill, remove by filter insoluble impurity after, be diluted to that to contain Mn be solution about 30g/l, in solution, drip the weak ammonia of concentration 10% below, and control terminal point pH is 8-9, generation Mn (OH) ₂Precipitation, Mn (OH) ₂Through behind the centrifuge dripping, dry immediately, 1000 ℃ of roastings 1～2 hour, after the cooling, use deionized water wash again, remove soluble impurity in the product, after the drying, can obtain trimanganese tetroxide.

Adopt the present invention, owing to use ammoniacal liquor, it can not introduce other impurity metal ions (as Na ⁺, K ⁺), and it is cheap and easy to get, can reduce the manufacturing cost of trimanganese tetroxide, the Mg in the sulfate liquor has been avoided in control pH＜9 ²⁺Generate Mg (OH) ₂And take in the product, owing to use ammoniacal liquor to do precipitation agent, Mn ²⁺The tendency that generates soluble complexes with ammonia is arranged, so Mn ²⁺Be precipitated as Mn (OH) ₂Turnover ratio be not very high, the soluble M n in the filtrate can with the carbon ammonium as precipitation agent, make it be converted into MnCO ₃And reclaim.

The invention will be further described below with reference to embodiment:

Embodiment

MnSO as shown in table 1 will be formed ₄H ₂The O water is mixed with 38oBe ^-(knowing that by analysis containing Mn is 133.2g/l) left standstill 48 hours, removed by filter insoluble impurities, got solution 11, and (this moment, concentration was about 9oBe to be diluted with water to 5l ^-, contain the about 30g/l of Mn).Stir fast add slowly down 8% weak ammonia to pH be about 8.5, be heated to about 70 ℃, be incubated 1 hour, suction filtration, centrifuge dripping, 100 ℃ of dry down Mn (OH) that get ₂Intermediate product 130g.In filtrate, add an amount of carbon ammonium, recyclable MnCO ₃100g, 1000 ℃ of following roastings 2 hours, the cooling back promptly got trimanganese tetroxide 90g with the deionized water repetitive scrubbing several times after the drying with intermediate product, and analytical results is listed table 2 in.

Table 1 MnSO ₄H ₂O forms

Composition	????Mn	????K	????Na	????Ca	??Mg
						Content (%)	??31.9	??0.36	??0.06	??0.35	??0.1

Table 2 Mn ₃O ₄The main component analytical results

Composition	??Mn	????K	????Na	????Ca	????Mg	??SO 4 2-
							Content (%)	??72.84	??0.002	??0.003	Do not detect	??0.008	Do not detect

Claims (4)

1. the manufacture method of a trimanganese tetroxide is characterized in that: add weak ammonia in manganese sulfate solution, and control endpoint pH, promptly generate Mn (OH) ₂Precipitation with this precipitate and separate, drying, roasting, cooling, washing, again after the drying, promptly obtains the high purity trimanganese tetroxide.

2. in the manufacture method according to the described a kind of trimanganese tetroxide of claim 1, the endpoint pH of control reaction is 8～9.

3. according to the manufacture method of the described a kind of trimanganese tetroxide of claim 1, it is characterized in that: obtain Mn (OH) ₂, 1000 ℃ of following roasting Mn (OH) ₂And make trimanganese tetroxide, become the trimanganese tetroxide after scouring in roasting.

4, according to the manufacture method of the described a kind of trimanganese tetroxide of claim 1, it is characterized in that: the soluble M n in the reaction mother liquor ²⁺With precipitation agent NH ₄HCO ₃Effect is converted into precipitation MnCO ₃