JPS58174531A - Reuse of maraging steel scrap - Google Patents

Abstract

PURPOSE:To recover an alloy having the same purity as that of electrolytic metal from the scrap of maraging steel for its reuse, by removing Mo with a predetermined ratio or more from a liquid containing Fe, Ni and Co prepd. by dissolving the scrap of maraging steel in hydrochloric acid or the like, and then electrolyzing the residual liquid. CONSTITUTION:The cast flashes, machining chips, scraps or the like of maraging steel comprising Fe, Ni, Co, Mo, Ti, etc. are dissolved in dil. sulfuric or hydrochloric acid until the liquid comes in the vicinity of pH=1.5-3.5 at a room temp., for instance. Hence almost all of Ti is precipitated, while Mo is precipitated to a degree such that it remains at a ratio of 20-1,200ppm in the liquid depending on conditions. Thereafter, the precipitates are removed, and the acid dissolved liquid of Mo content at 0-6mg/l is electrolyzed. Consequently, a Fe-Ni-Co alloy having the same purity as that of electrolytic metal useful as a raw material for melting maraging steel requested to have high-grade quality is recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reusing casting waste, cutting waste, and maraging steel scrap generated during the processing of maraging steel as raw materials for making maraging steel.

Traditionally, iron-based metal scraps have been recycled using the so-called "dry process," which involves melting them in an electric furnace and refining them through a reaction between the molten metal and slag, or by smelting or powder injection. In general, maraging steel is no exception.

However, when this dry method is used to regenerate maraging steel, there are the following problems.

l In atmospheric melting and blowing, which are dry scouring processes, Aj and Ti contained as components of the recycled material oxidize and become fine inclusions that are dispersed in the recycled material, but unlike maraging steel, Furthermore, the presence of inclusions is undesirable in materials characterized by high stress and 1 Ifi, since minute inclusions can also cause abnormal rupture.

First, vacuum melting is used for K to avoid oxidation of the TL, but maraging steel has a strong springback property, so even if a large volume of waste is melted, the recovered metal cannot be melted. Since the amount of 11Jc is small, the number of patches increases and vacuum breaking and suction must be repeated, which is uneconomical. Furthermore, in vacuum melting, it is difficult to remove S contamination, which hinders the recycling of recycled materials.
Come.

Since the removal of impurities must be carried out in the molten state, the method is naturally limited.

On the other hand, if the maraging steel scraps are dissolved in acid and the acid solution is electrolyzed, the so-called "wet method" completely eliminates the difficulties encountered with the dry method. It was found that it was impossible to deposit metal on the cathode and recover it using simple treatments.

The present invention eliminates the above-mentioned drawbacks of the prior art and achieves a high level of quality! The object of the present invention is to obtain a method for recycling maraging steel waste that can provide a high-purity alloy equivalent to electrolytic metal as a raw material for melting maraging steel.

In the present invention, 1. In order to achieve this objective, maraging steel waste is dissolved in hydrochloric acid or sulfur and Fe, Ni
A solution containing , and CO is prepared, and Mo 9 degrees in this solution is /
! *, after removing KMo to be less than '9711,
This solution is characterized by recovering Fs, Ni, and Co as a high-purity alloy for use as raw materials for melting by electrolysis.

Hereinafter, the present invention will be explained in detail based on examples thereof.

Thing steel is p&, Ni, Co.

It is composed of Mo, T1, etc., and when dissolved with dilute sulfuric acid or dilute hydrochloric acid, the pH at room temperature is /,!
−' J, dissolution continues until it reaches around k.

In this case, T1 is after elution. TlO2 undergoes hydrolysis
Mo also precipitates as a lower oxide, but? 1:1:Almost the entire amount of 1 precipitates, whereas Mo
Depending on the conditions, about θHl and 7opm remain in the liquid.

The present inventors electrolyzed this solution to produce Fe and Ni.

An attempt was made to recover Co as an alloy, but a black precipitate adhered to the cathode surface, and Fs, Ni, and C were collected.

confirmed that no deposits could be observed under conditions with a metallic luster, such as those obtained by ordinary electrolysis. Therefore, the present inventors investigated the cause of interference with metal deposition caused by electrolysis on nails, and found that the cause was related to Mo9 degree in the liquid.

That is, when Mo Y was removed stepwise from an acid solution of maraging steel and electrolyzed, the results shown in the table were obtained.

Table From this table, Mo 9 degrees in the electrolyte is 0-A”f!
/43, the precipitated metal is Fe.

It is collected as an alloy of Ni and Co, but 4S/! ! '9
/J3, it is recovered as a slightly brittle metal with molybdenum oxide added, and these can be used as raw materials for melting. However, if the Mo concentration is 1
If rq is 71 or more, Mo 1! ! It can be seen that only compounds are precipitated and the metal cannot be recovered.

In addition, the molybdenum concentration is also affected by the sum of the current efficiency of metal recovery, and when the Mo concentration in the electrolyte is 7"l/A, the precipitated alloy (the current efficiency for it is 1796, but /-call/!
At the time of ri! -, and is estimated to be around 70% for /j ``j' / J3, so from this perspective, /!119/JJ is M.

It can be thought of as a concentration limit.

- 10,000, usually in an alloy containing Fe, Ni, Co? is oxidized to form Fe, precipitated and removed, and then Ni and Co are recovered. This precipitate of Fe is used as red iron material, but even after undergoing processes such as filtration, washing, drying, and calcination to recover it, red iron material is only valued at about 300,000 yen per ton. ,
Along with the precipitation, Ni and Co of 10S co-precipitate and are lost.

On the other hand, in the present invention, Fe
This eliminates the cost of producing TPe precipitate into red iron oxide and the loss of NL and Co (instead of #c).

This is used as an alternative to electrolytic iron (which is used as a substitute) when manufacturing the marage area.The price of electrolytic iron is about 30
Although the cost is 10,000 yen, the required power is 1,000 KW, and even if the electricity price is 10 yen/Kw, it will only cost 1,000 yen, which shows that it is much more advantageous than red iron production.

As mentioned earlier, the conventional recycling of maraging steel is by the dry method, but this dry method has the serious drawback that it is difficult to completely remove inclusions. In the wet method, this drawback is completely eliminated and high-purity metals can be obtained, but it has been impossible to deposit and recover the metals on the cathode by electrolysis due to the rough treatment of the strong solution. Y1 In the present invention, the reason why metal precipitation cannot be recovered by this wet method is Mo in the component.
We determined the limit amount of Fe, Ni, and C by electrolysis.

It was successfully recovered as an alloy, which made it possible to produce a low-sulfur smelting raw material containing almost no inclusions from mah-aging steel scraps, which could not be done using conventional methods.

When the raw materials are dissolved by salting, recovered metals with extremely low sulfur can be obtained by the strawberry liquid treatment 11j.

It is clear that this method can also be applied to the recovery of alloy waste containing Fe and Mo 2 without being contaminated.

Patent applicant: Mitsubishi Steel Corporation 17

Claims (1)

[Claims] l F by dissolving maraging steel scraps in hydrochloric acid or sulfuric acid.
A solution containing Fe, Ni, and Co is prepared9, KMo is removed from this solution so that the MO concentration in the solution is below a certain value, and then this solution is electrolyzed to produce Fe and N1.
, Cn is recovered as a high-purity dark alloy for use as a raw material for smelting. A reuse method described in Section I of Scope Series I of Patent No. 1.11 trillion, in which the MO loss in a liquid containing Fe, Ni, and Co is reduced to /j''P/J or less.