阅读说明：本技术 一种有机硅单体合成浆渣的处理方法 (Treatment method of organic silicon monomer synthetic pulp slag ) 是由 王海栋 谢谋证 胡应如 黄晓辉 柯尊鹏 于 2020-05-08 设计创作，主要内容包括：一种有机硅单体合成浆渣的处理方法,将浆渣水解产物中和石灰石,所产生的滤液分为两部分,一部分返回水解釜继续促进水解,一部分进入浓缩器,生产可销售的氯化钙溶液,合理调整这两部分滤液的分配比能够使氯化钙溶液的生产连续进行,浆渣水解产物氯化氢不会污染环境,实现有机硅生产过程中其它水解产物的回收利用,使得资源的回收利用最大化。本发明合理利用水解产物过滤后的废渣,废渣燃烧产生的热量对中和产物氯化钙溶液进行蒸发浓缩,降低了能耗和处理成本。本发明使得铜等对环境有害的金属转化为对环境无害的稳定的氢氧化物沉淀,解决了环保问题。(A method for treating the slurry dregs generated by synthesizing organosilicon monomer includes such steps as neutralizing lime stone with the hydrolysate of slurry dregs, dividing the filtrate into two parts, returning one part to hydrolysis kettle for promoting hydrolysis, and returning another part to concentrator for producing the calcium chloride solution which can be sold. The method reasonably utilizes the waste residue after the hydrolysate is filtered, and the heat generated by the waste residue combustion evaporates and concentrates the neutralization product calcium chloride solution, thereby reducing the energy consumption and the treatment cost. The invention converts the metals harmful to the environment, such as copper, into the stable hydroxide precipitate harmless to the environment, thereby solving the problem of environmental protection.)

1. The method for treating the organic silicon monomer synthetic pulp slag is characterized by comprising the following steps of:

s1, uniformly mixing the organic silicon monomer synthetic slurry residue with the waste acid liquid A and/or water in a hydrolysis kettle, hydrolyzing to obtain a hydrolysate a, filtering the hydrolysate a to obtain waste acid water b and waste residue b₁；

S2, mixing the waste slag b obtained in the step S1₁Sending the waste acid water b into a neutralization tank to be neutralized with limestone, settling a neutralization product c, sending supernatant to a filter press to obtain filtrate d and waste residue d₁；

S3, mixing the waste residue d obtained in the step S2₁Sending the filtrate d to an incinerator system for incineration, and dividing the filtrate d obtained in the step S2 into two parts d₀₁And d₀₂，d₀₁Circularly returning to the hydrolysis kettle to perform hydrolysis reaction with the pulp residue, d₀₂Sending to a concentrator, evaporating and concentrating by using the heat of the flue gas of the incinerator system to obtain concentrated calcium chloride solution f and condensed water e, and circulating the condensed water eReturning the water to the hydrolysis kettle for hydrolysis;

s4, feeding the calcium chloride solution f into a pH adjusting tank, adding lime milk to adjust the pH, settling, performing filter pressing to recover hydroxide precipitates of metal ions, and adjusting the pH of the filtrate to be neutral by using a hydrochloric acid solution to obtain a saleable calcium chloride solution;

and step S1, the waste acid liquid A is waste acid water generated by the hydrolysis of the organic silicon monomer when the first kettle is started.

2. The process according to claim 1, wherein the concentration of HCl in the spent acid solution A is 3 to 8 wt.%.

3. The process of claim 1, wherein when the specific gravity of the filtrate d in step S3 is p < 1.14, d is₀₂The flow rate is 0; when ρ > 1.20, d₀₁The flow rate is 0; when rho is more than or equal to 1.14 and less than or equal to 1.20, d₀₁And d₀₂The flow distribution ratio is automatically adjusted within the range of 1-5: 1.

4. The method according to claim 3, wherein the filtrate d and the acid waste water produced by hydrolysis of the organosilicon in the acid pickle A in the hydrolysis kettle after the start of the cycle₀₁The flow ratio of (A) is 1:2 to 1:10, preferably 1:2 to 6.

5. The treatment method as claimed in claim 1, wherein the flow rate of the waste acid liquid A in step S1 is 8000-13000 kg/h.

6. The method as claimed in claim 1, wherein the slurry residue obtained in step S1 has a solid content of 25-35%, a boiling point of 150-.

7. The process of claim 1, wherein the flue gas temperature of the incinerator system for evaporative concentration in step S3 is 120-.

8. The treatment method of claim 1, wherein the lime milk is adjusted to pH 9-11 and the hydrochloric acid solution is adjusted to pH 6-8 in step S4.

Technical Field

The invention relates to the technical field of waste recycling, in particular to a method for treating organic silicon monomer synthetic pulp slag.

Background

The organosilicon material is composed of a main chain formed by alternately arranging silicon atoms and oxygen atoms and an organic group structure connected with the silicon atoms, and the structure endows the organosilicon material with excellent temperature resistance, dielectric property, physiological inertia, low surface tension and other properties, so that the organosilicon material is widely applied to the technical fields of aerospace, military, electronics and electrics, textile and paper making, buildings, chemistry, coatings, medicines and the like.

With the application and popularization of organosilicon materials, the demand of organosilicon materials is increasing, and among a plurality of organosilicon monomers used for preparing organosilicon materials, the dosage of methylchlorosilane is the largest (accounts for more than 90%), and the dosage of methylchlorosilane is also increasing. Therefore, the discharge amount of three wastes in the synthesis process of the methyl chlorosilane is increased, wherein the organic silicon waste slurry residue is the largest discharge amount, and the discharge amount accounts for about 2 wt% of the mixed monomer. The organosilicon waste slurry residue is a flowable solid-liquid mixture, the liquid phase is mainly a high-boiling-point organosilane mixture, the solid phase mainly comprises suspended silicon powder, copper, magnesium and other metals, and if the organosilicon waste slurry residue is exposed in the air, the organosilane in the organosilicon waste slurry residue can be spontaneously combusted and can react with water in the air to form acid mist, so that the solid-liquid mixture cannot be directly discharged and needs to be subjected to harmless treatment.

Patent CN200310115386.2 discloses a method for treating organic silicon waste slurry, which comprises the steps of separating most of high-boiling residues and 70% of high-viscosity slurry from slurry with a solid content of 20% by centrifugal gravity settling, further hydrolyzing the 70% of high-viscosity slurry, and further recovering copper enriched in the slurry in a hydrolysis solution.

Patent CN201510806447.2 discloses a method for treating pulp dregs in the process of synthesizing organosilicon monomers, wherein dilute acid water is adopted to hydrolyze organosilicon pulp dregs, the dilute acid water after hydrolysate is kept still and settled returns to a hydrolysis tank to participate in hydrolysis, the problem of acid required by hydrolysis is solved to a certain extent, but a sewage treatment unit is required to be arranged and sufficient dilute acid with the concentration of more than 8% of new water is required to be prepared, the space utilization rate is reduced, the cost is also improved, on the other hand, the method does not consider the further treatment of hydrolyzed solid dregs and directly transports the solid dregs away by a loader, wherein metals harmful to the environment, such as copper, and the like, are not completely harmlessly treated, and a large amount of waste of effective resources is caused.

Patent CN201910622601.9 discloses a recovery process of organic silicon waste acid containing tri-n-butylamine, siloxane and aluminum chloride, which relates to the problem of recovering hydrogen chloride generated by catalytic cracking of high-boiling-point substances and can realize the complete recovery of the hydrogen chloride, a catalyst and the siloxane, but relates to a continuous cyclic concentration evaporation process to break azeotropic hydrochloric acid and resolve hydrogen chloride gas, and the process needs to consume a large amount of heat energy and has high cost. Patent CN201910035530.2 discloses an organosilicon wastewater treatment system and method, although the obtained sodium chloride can be reused as industrial salt, the multi-effect evaporation consumes additional electric energy and steam. Patent cn201820804330.x discloses a production line for producing calcium chloride and aluminum hydroxide by using waste, which is a process for producing calcium chloride by using waste acid and white mud, but spray drying also has the problem of high energy consumption.

Therefore, there is an urgent need to develop a process method capable of performing innocent treatment on the organosilicon slurry slag to maximize the recycling of resources, reduce energy consumption and cost, reduce environmental pollution and reduce treatment cost.

Disclosure of Invention

The invention aims to provide a method for treating organic silicon monomer synthetic pulp slag, which solves the problem of incomplete harmless treatment of organic silicon pulp slag in the prior art, can fully utilize hydrogen chloride generated by hydrolysis of the organic silicon pulp slag to generate a recyclable calcium chloride solution, eliminates the potential safety hazard of directly discharging acid mist, can realize recycling of other hydrolysate of the pulp slag, and maximizes the recycling of resources; the hydrogen chloride generated by the hydrolysis of the pulp residue has two purposes, one part is returned to promote the hydrolysis of the pulp residue, the other part is used for producing calcium chloride, and meanwhile, the heat of the flue gas of the incinerator is utilized to concentrate the calcium chloride solution with lower concentration, so that the requirement of the content (30 +/-0.5 wt%) of the calcium chloride solution sold outside is met, the economic value is created, and the treatment cost is greatly reduced.

The method for treating the organic silicon monomer synthetic pulp slag is characterized by comprising the following steps of:

s1, uniformly mixing organic silicon monomer synthetic slurry residues with a waste acid solution A and/or water in a hydrolysis kettle, hydrolyzing to obtain a hydrolysate a, filtering the hydrolysate a to obtain waste acid water b and waste residues b₁；

S2, using the waste residue b in the step S1₁Sending the waste acid water b into a neutralization tank to be neutralized with limestone, settling a neutralization product c, sending supernatant to a filter press to obtain filtrate d and waste residue d₁；

S3, using the waste residue d obtained in the step S2₁Sending the filtrate d to an incinerator system for incineration, and dividing the filtrate d obtained in the step S2 into two parts d₀₁And d₀₂，d₀₁Circularly returning to the hydrolysis kettle to perform hydrolysis reaction with the pulp residue, d₀₂Sending to a concentrator, and carrying out evaporation concentration by using the heat of the flue gas of the incinerator system to obtain a concentrated calcium chloride solution f and condensed water e, wherein the condensed water e is used as circulating water and returns to the hydrolysis kettle for hydrolysis;

s4, feeding the calcium chloride solution f into a pH adjusting tank, adding lime milk to adjust the pH, settling, performing filter pressing to recover hydroxide precipitates of metal ions, and adjusting the pH of filtrate to be neutral by using a hydrochloric acid solution to obtain a saleable calcium chloride solution;

step S1, starting the first kettle, wherein the waste acid liquid A is waste acid water generated by hydrolysis of an organic silicon monomer, and after the first starting cycle begins, the waste acid liquid A comprises pure water, waste acid water generated by hydrolysis of organic silicon, and d₀₁And condensed water e.

The HCl concentration in the waste acid liquid A is 3-8 wt%.

D at step S3₀₁And d₀₂The flow distribution ratio of the two is determined byThe specific gravity rho of the filtrate d is less than 1.14₀₂Flow 0, i.e. no feed to the concentrator, when p > 1.20, d₀₁The flow is 0, namely the water is not returned to the hydrolysis kettle; when rho is more than or equal to 1.14 and less than or equal to 1.20, d₀₁And d₀₂The flow distribution ratio is automatically adjusted within the range of 1-5: 1.

After circulation begins, waste acid water and filtrate d generated by hydrolyzing organic silicon in the waste acid liquid A in the hydrolysis kettle₀₁The flow ratio of (A) is 1:2 to 1:10, preferably 1:2 to 6.

d₀₁And d₀₂The flow distribution ratio of the slurry residue and the calcium chloride can ensure that the hydrolysis reaction of the slurry residue can not be caked in a proper range, the blockage and the preparation of the calcium chloride are continuously carried out, so that the slurry residue hydrolysate, namely the hydrogen chloride, can not pollute the environment, and can be utilized to the maximum extent, and a calcium chloride solution product is generated.

The flow rate of the waste acid liquid A in the step S1 is 8000-13000 kg/h.

In the step S1, the solid content of the slurry slag is 25-35%, the boiling point is 150-180 ℃, and the feeding flow rate of the slurry slag is 400-800 kg/h.

The incinerator system flue gas temperature for evaporative concentration at step S3 is 120-.

Step S4, the pH of the lime milk is adjusted to 9-11, and the pH of the hydrochloric acid solution is adjusted to 6-8.

The organosilicon monomer of step S1 is not particularly limited, and includes, but is not limited to, organochlorosilanes.

Compared with the prior art, the invention has the beneficial effects that:

firstly, the organic silicon slurry residue is thoroughly treated in a harmless manner, hydrogen chloride generated by hydrolysis of the organic silicon slurry residue can be fully utilized to generate a recyclable calcium chloride solution, potential safety hazards of acid mist generated by direct discharge are eliminated, the hydrolysate can be recycled in the organic silicon production process, and the resource recycling maximization is realized.

The waste residue after the hydrolysate is filtered is reasonably utilized, and the heat generated by the waste residue combustion is used for evaporating and concentrating the neutralized product calcium chloride solution, so that the low-concentration calcium chloride is concentrated to the concentration of 30 +/-0.5 wt% of a commercial product, and the energy consumption and the treatment cost are reduced.

The method can continuously carry out the hydrolysis of the slurry residue and the preparation of the calcium chloride solution, and has the advantages of simple process, convenient operation, energy conservation, emission reduction, no environmental pollution and low cost.

The invention converts the metals harmful to the environment, such as copper, into the stable hydroxide sediment harmless to the environment, thereby solving the problem of environmental protection.

Drawings

FIG. 1 is a process flow diagram of example 1 of the present invention.

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited to the descriptions in the following. Unless otherwise specified, "parts" in the examples of the present invention are parts by weight. All reagents used are commercially available in the art.

Example 1

S1, conducting hydrolysis after uniformly mixing the methyl chlorosilane monomer synthetic slurry residues with a flow rate (solid content is 28%, boiling point is 175 ℃) of 500kg/h and a waste acid solution A consisting of waste acid water and pure water in a dimethyl dichlorosilane hydrolysis process with a flow rate of 10000kg/h, wherein the HCl concentration in the waste acid solution A is 3 wt% in a hydrolysis kettle to obtain a hydrolysis product a, and filtering the hydrolysis product a by using a slag hopper filter vehicle to obtain waste acid water b and waste slag b₁；

S2, mixing the waste slag b obtained in the step S1₁Sending the waste acid water b into a neutralization tank to neutralize limestone in the tank, settling a neutralization product, pumping supernatant liquor c to a filter press to obtain filtrate d and waste residue d₁；

S3 waste residue d₁Harmless treatment in incinerator, testing filtrate d with online densitometer, measuring specific gravity rho of 1.11, less than 1.14, and calcium chloride concentration in filtrate d is too low to concentrate, i.e. d₀₂Measuring the flow rate to 0, returning all the filtrate d to a hydrolysis kettle for cyclic hydrolysis, circulating for 1 time, measuring the specific gravity of the filtrate d to be 1.15, wherein rho is more than or equal to 1.14 and less than or equal to 1.20, and measuring a part of the filtrate d according to the flow rate d₀₂Delivering to a concentrator, and collecting the other part at flow rated₀₁Returning to the hydrolysis kettle, d₀₁And d₀₂The flow distribution ratio is automatically adjusted by equipment and is shown to be 2:1, and the waste acid water and the filtrate d generated by hydrolysis of the dimethyldichlorosilane₀₁The flow ratio of the (1: 2) is kept, meanwhile, 500kg/h of methyl chlorosilane monomer synthetic slurry residues (with the solid content of 28 percent and the boiling point of 175 ℃) are kept, the waste acid liquor A10000kg/h is injected into a hydrolysis kettle (with the HCl concentration of 3 percent in the waste acid liquor A) for continuous production, at the moment, the flue gas temperature of an incinerator system for heating a concentrator is 180 ℃, the flue gas outlet temperature is 120 ℃, evaporation concentration is carried out for 8 hours, the material temperature in the concentrator reaches 111 ℃, sampling is carried out to quickly test the specific gravity, the calcium chloride concentration is analyzed, the calcium chloride concentration reaches 30 percent by weight, and partial concentrated solution f can be extracted while the filtrate is taken to obtain the calcium chloride solution f of the concentrated solution, and the condensate water e returns to the hydrolysis kettle for hydrolysis;

s4, feeding the calcium chloride solution f into a pH adjusting tank, adding lime milk to adjust the pH to 10, settling and filter-pressing the mixed solution with the precipitate to recover hydroxide precipitate of metal ions such as copper, magnesium, iron and the like, and adjusting the pH of the filtrate to 7 by using a hydrochloric acid solution with the concentration of 30% to obtain a saleable product calcium chloride solution with the concentration of 30 +/-0.5 wt%.

Example 2

The same as example 1 except that the HCl concentration in the spent acid solution A in step S1 is 5 wt%, the specific gravity p measured in step S3 for the first time is 1.17, 1.17 is 1.14-1.20, and a part of the filtrate d is fed at a flow rate d₀₂Delivering to a concentrator, and delivering the other part at a flow rate d₀₁Returning to the hydrolysis kettle, d₀₁And d₀₂The flow distribution ratio is automatically adjusted by equipment and is shown to be 2:1, and the waste acid water and the filtrate d generated by hydrolysis of the dimethyldichlorosilane₀₁The flow ratio of (1: 4) is kept, meanwhile, the methyl chlorosilane monomer synthesis slurry residue (with the solid content of 28 percent and the boiling point of 175 ℃) is injected into a hydrolysis kettle (with the HCl concentration of 5 percent by weight in the waste acid liquid A) at 500kg/h and the waste acid liquid A10000kg/h for continuous production, the steps of the example 1 are carried out in sequence, and finally, the saleable product calcium chloride solution with the concentration of 30 +/-0.5 percent by weight is obtained.

Example 3

The same as example 1 except that the HCl concentration in the spent acid solution A in step S1 was 8wt%, step S3 first measures the specific gravity p to be 1.19, and a part of the filtrate d is measured at a flow rate d₀₂Delivering to a concentrator, and delivering the other part at a flow rate d₀₁Returning to the hydrolysis kettle, d₀₁And d₀₂The flow distribution ratio is automatically adjusted by equipment and is shown to be 3:1, and the waste acid water and the filtrate d generated by the hydrolysis of the dimethyldichlorosilane₀₁The flow ratio of (1: 6) is kept, meanwhile, the methyl chlorosilane monomer synthesis slurry residue (with the solid content of 28 percent and the boiling point of 175 ℃) is injected into a hydrolysis kettle (with the HCl concentration of 8 percent by weight in the waste acid liquid A) at 500kg/h and the waste acid liquid A10000kg/h for continuous production, the steps of the example 1 are carried out in sequence, and finally, the saleable product calcium chloride solution with the concentration of 30 +/-0.5 percent by weight is obtained.

Example 4

Otherwise, the same as example 1 was repeated, except that the spent acid solution A was replaced with pure water in step S1, and that the specific gravity ρ of the filtrate d was measured to be 1.03 and much less than 1.14 in step S3 for the first time, and that the concentration of calcium chloride in the filtrate d was too low to consume much heat and thus it was not suitable for concentration, that is, d is d₀₂Measuring flow rate to 0, returning all filtrate d to hydrolysis kettle for cyclic hydrolysis, circulating until 4 times of circulation, measuring specific gravity of filtrate d between 1.14 and 1.20 at 5 th time to 1.18, and collecting part of filtrate d at flow rate d₀₂Delivering to a concentrator, and delivering the other part at a flow rate d₀₁Returning to the hydrolysis kettle, d₀₁And d₀₂The flow distribution ratio is automatically adjusted by equipment to show that the flow distribution ratio is 1:2, and the waste acid water and the filtrate d generated by hydrolysis of the dimethyldichlorosilane₀₁The flow ratio of the acid liquor A to the methyl chlorosilane monomer synthetic slurry is 1:2, the methyl chlorosilane monomer synthetic slurry is kept at 500kg/h (the solid content is 28 percent, the boiling point is 175 ℃), the waste acid liquor A10000kg/h is injected into a hydrolysis kettle (the HCl concentration in the waste acid liquor A is 3 percent by weight), continuous production is carried out, and the saleable product calcium chloride solution with the concentration of 30 +/-0.5 percent by weight is finally obtained.

Comparative example 1

The process is the same as example 1 except that the filtrate d is returned to the hydrolysis reactor to promote hydrolysis of the sludge, and the filtrate d is mixed with the waste acid water from hydrolysis of dimethyldichlorosilane₀₁The flow ratio of (A) to (B) is 1:10, the hydrolysis kettle is caked, the blanking pipe is blocked, and the production cannot be continuously carried out.

Comparative example 2

At 15m³5000kg of pure water is added into an enamel slurry residue hydrolysis kettle in advance, stirring is started, 1000kg/h of methyl chlorosilane monomer synthetic slurry residue is added, the flow of the added pure water is 10000kg/h, the liquid level of the hydrolysis kettle is automatically controlled, a hydrolysis product a is intermittently discharged from a bottom valve of the hydrolysis kettle, waste residues are obtained by filtering through a residue hopper filter and are sent to a burning device, and filtrate b flows into a neutralization pond to react with limestone in the neutralization pond and then is sent to a sewage treatment station for further treatment.

Comparative example 3

The rest was the same as in comparative example 2, except that pure water was replaced with waste acid (HCl concentration of 3 wt%) obtained from the methylchlorosilane hydrolysis step.

The calcium chloride solutions prepared in the above examples and comparative examples were tested with reference to the standard GB/T26520-2011 and the results are shown in table 1.

The energy consumption and cost for treating the pulp slag per unit weight in the above examples and comparative examples are statistically summarized, and the results are shown in Table 2.

TABLE 1

TABLE 2

The organic silicon slurry residue is thoroughly treated in a harmless manner, hydrogen chloride generated by hydrolysis of the organic silicon slurry residue can be fully utilized to generate a recyclable calcium chloride solution, potential safety hazards of acid mist generated by direct discharge are eliminated, other hydrolysis products in the organic silicon production process can be recycled, and the resource recycling is maximized.

The method reasonably utilizes the waste residue after the hydrolysate is filtered, and the heat generated by the waste residue combustion is used for evaporating and concentrating the neutralized product calcium chloride solution, so that the low-concentration calcium chloride is concentrated to 30 +/-0.5 wt% of the concentration of the commercial product, and the energy consumption and the treatment cost are reduced.

The method can continuously carry out hydrolysis of the pulp residue and preparation of the calcium chloride solution, has the advantages of simple process, convenient operation, energy conservation, emission reduction, no environmental pollution, low cost and obvious economic value of cost reduction and efficiency improvement of each ton of pulp residue. The produced calcium chloride solution can be used as a sewage treatment refrigerant, a coagulant in the building industry, a building antifreezing agent and a quenching agent in the ferrous metallurgy industry.

The invention converts the metals harmful to the environment, such as copper, into the stable hydroxide precipitate harmless to the environment, thereby solving the problem of environmental protection.

The above detailed description is specific to one possible embodiment of the present invention, and the embodiment is not intended to limit the scope of the present invention, and all equivalent implementations or modifications without departing from the scope of the present invention should be included in the technical scope of the present invention.